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A randomised controlled trial of yoga for the treatment of chronic low back pain: Results of a pilot study
Complementary Therapies in Clinical Practice 16 (2010) 187e193
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A randomised controlled trial of yoga for the treatment of chronic low back pain: Results of a pilot studyq Helen Cox a, *, Helen Tilbrook a, John Aplin b, Anna Semlyen c, David Torgerson a, Alison Trewhela d, Ian Watt a a
Department of Health Sciences, SRB Area 4, University of York, York YO10 5DD, United Kingdom Division of Human Development, St Mary’s Hospital, Manchester, United Kingdom British Wheel of Yoga Teacher, Friends Meeting House, Friargate, York, United Kingdom d Iyengar Yoga Teacher, ZedShed, Jubilee Wharf, Penryn, United Kingdom b c
a b s t r a c t Keywords: Pilot study Feasibility RCT Yoga Low back pain Primary care
Objective: To conduct a pilot trial of yoga for the treatment of chronic low back pain (LBP) to inform the feasibility and practicality of conducting a full-scale trial in the UK; and to assess the efficacy of yoga for the treatment of chronic low back pain. Design: A pragmatic randomised controlled trial was undertaken comparing yoga to usual care. Participants: Twenty participants who had presented to their GP with chronic low back pain in the previous 18 months were recruited via GP records from one practice in York, UK. Interventions: Twenty patients were randomised to either 12 weekly 75-min sessions of specialised yoga plus written advice, or usual care plus written advice. Allocation was 50/50. Main outcome measures: Recruitment rate, levels of intervention attendance, and loss to follow-up were the main non-clinical outcomes. Change as measured by the Roland and Morris disability questionnaire was the primary clinical outcome. Changes in the Aberdeen back pain scale, SF-12, EQ-5D, and pain selfefficacy were secondary clinical outcomes. Data were collected via postal questionnaire at baseline, 4 weeks, and 12 weeks follow-up. Results: Of the 286 patients identified from the GP database, 52 (18%) consented and returned the eligibility questionnaire, out of these 20 (6.9%) were eligible and randomised. The total percentage of patients randomised from the GP practice population was 0.28%. Ten patients were randomised to yoga, receiving an average of 1.7 sessions (range 0e5), and 10 were randomised to usual care. At 12 weeks follow-up data was received from 60% of patients in the yoga group and 90% of patients in the usual care group (75% overall). No significant differences were seen between groups in clinical outcomes apart from on the Aberdeen back pain scale at four weeks follow-up where the yoga group reported significantly less pain. Conclusion: This pilot study provided useful data and information to inform the design and development of a full-scale trial of yoga for CLBP in the UK. A key finding is the calculation of GP practice total list size required for patient recruitment in a full-scale trial, and the need to implement methods to increase class attendance. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Most people will experience at least one episode of low back pain (LBP) during their life and in developed countries the reported
q This study was funded by York Trials Unit, Department of Health Sciences, University of York. * Corresponding author. Tel.: þ44 01904 321614; fax: þ44 01904 321387. E-mail address: [email protected] (H. Cox). 1744-3881/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ctcp.2010.05.007
lifetime prevalence varies from 49% to 70% with point prevalences from 12% to 30%.1,2 In 1998 the UK Department of Health (DoH) presented results prepared by the Government Statistical Service on the prevalence of LBP in the UK and reported that 40% of adults said they had suffered from LBP lasting more than one day in the previous 12 months, with 15% of LBP sufferers reporting chronic pain throughout the year. Nearly 40% of LBP sufferers consulted a GP for help; 10% visited a practitioner of complementary medicine (osteopaths, chiropractors and acupuncturists); and 5% of LBP sufferers aged 16e64 in employment had taken time off work
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during the previous month because of LBP.3 More than 1000 randomised controlled trials (RCTs) have been published evaluating all types of conservative, complementary, or surgical treatments for LBP. Current evidence based guidelines for the management of LBP suggest that exercise and keeping mobile is helpful.4 However, evidence from RCTs are mixed and many have shown that exercise treatment, though widely used and recommended, has shown only a small and short-term effect on LBP.5,6 Unfortunately many commonly used interventions for LBP lack sufficient evidence for clinically relevant long-term effects,7,8 and patients are generally unsatisfied with current levels of care, hence the need for further rigorous research to seek alternative methods of reducing LBP and increasing mobility in those with back problems. Yoga is an increasingly popular therapy which offers a combination of physical exercise with mental focus that may make it a suitable therapy for the treatment of LBP. The practice of yoga focuses on the control of muscle functions using a sequence of postures. Progression through the sequence and meditation is intended to challenge muscle strength, joint flexibility and balance. Yoga is potentially a very cost effective treatment as it can be delivered in group sessions. The potential for yoga to have a longer term influence is more likely than, for example, manipulation and exercise therapy, as yoga participants will be encouraged to practice the technique at home, between classes, and to continue with home practice after the classes have been completed. A systematic review of the literature revealed four full-scale RCTs9e12 and three pilot RCTs13e15 of yoga for LBP. Although results were mixed, all four of the full-scale trials showed statistically significant effects on LBP that favoured the yoga group. For example, Sherman et al.9 reported differences in disability at 3 months and 6 months follow-up, Williams et al.10 reported reductions in pain, functional disability and medication use at 3 months follow-up, Williams et al.11 reported a reduction in disability, pain and depression at 6 months follow-up, and Tekur et al.12 reported a reduction in disability post-intervention. However these trials were limited in that they were small, in some cases interventions were delivered by only one teacher resulting in lack of generalisibility, the clinical significance of the some of the studies is questionable, and duration of follow-up was short resulting in a lack of information regarding the possible longer term benefits of yoga. Of the three pilot trials two reported a significant improvements in the yoga group. Saper et al.14 reported a reduction in pain and medication use, and Williams et al.15 reported a reduction in functional disability and pain. The results from the above trials are promising, however all of the studies above were conducted outside of the United Kingdom (UK), mainly in the USA, follow-up did not exceed 6 months, and patients were recruited by self-referral. The health care system in the UK differs greatly to that of the USA and, as far as we are aware, a study of this kind has not been conducted in the UK. For these reasons further research into designing and executing a large RCT of yoga for LBP in the UK is warranted. The primary objective of this pilot study was to focus on establishing key design features, practicality and feasibility to inform a larger multicentre trial of the effectiveness of yoga for CLBP. This study was not powered to reach statistical or clinical significance. In particular we aimed to establish the potential recruitment rate, questionnaire design, levels of intervention attendance, and loss to follow-up. 2. Methods 2.1. Study design and setting This pilot RCT compared a 12 week course of specialised yoga back classes with usual care alone and was undertaken between
June and September 2007. The yoga group continued with their usual care and both groups received written information on how to manage their LBP in the form of a small booklet called The Back Book.16 Participants were recruited and randomised from one general practice in York, UK. 2.2. Recruitment and participants The practice manager searched their database using Read Codes to identify patients who had presented to their GP with LBP once or more within the previous 18 months. The GP practice excluded pregnant patients and patients under 18 or over 65 years of age. Identified patients were mailed out a recruitment pack from the GP practice containing an information sheet, consent forms, and a screening questionnaire. Patients who were interested in participating completed the pre-randomisation screening questionnaire and consent form and returned them to the University of York where their eligibility was assessed. The inclusion criteria were: aged 18e65 years; a score of 4 or more on the Roland and Morris Disability Scale (RDQ); had presented to their GP in the previous 18 months with LBP; can attend yoga classes (times and dates), and; sufficiently physically mobile (i.e. can get up off the floor unaided, and can walk up and down stairs). The exclusion criteria were: pregnant women; psychosis or recent substance abuse; already participating in yoga; already in a trial for their LBP; not currently suffering an episode of LBP; previous spinal surgery, and; clinical indications of serious spinal or neurological pathology as indicated by four ‘red flags’ (1) difficulty passing or controlling urine, (2) numbness around back passage or inner thighs, (3) numbness, pins and needles or weakness in both legs, and (4) unsteadiness on feet. All of this data was collected via the initial screening questionnaire. The details of those patients who were eligible to participate were then sent to their GP who second checked their eligibility against the patient’s records. Patients were then randomised using computer generated random numbers by an independent data manager to either 12 weekly classes of yoga or usual care. York Local Research Ethics Committee approved the study. 2.3. Interventions The yoga intervention consisted of 12 weekly 75-min classes and was devised by an Iyengar Yoga teacher (IYAUK) and LBP yoga specialist, in collaboration with a British Wheel of Yoga teacher (BWY), who delivered the intervention. The structure was based on that previously used in the US Karen Sherman yoga trial,9 whilst ensuring that a common ground was found between the two associations of IYAUK and BWY. Other influences included Geeta and B.K.S. Iyengar, who has taught yoga for over 70 years and has applied therapeutic variations of classical poses to many health problems including LBP.17 The yoga programme was introduced in a gentle graded way over the 12 weeks. Class 1 focused on relaxation and pain-relieving postures. Classes 2e6 taught the CORE practice sequences, which included settling/pacifying poses, standing poses to teach good posture, improve flexibility in the upper back and shoulders, then chair-seated posture-strengthening poses. These were followed by simple supine and prone floor poses, to give strength, mobility and further postural understanding and to allow the students to learn a good grounding in the fundamental starting points of the majority of yoga pose types. Classes 7e12 built upon the CORE Practices poses, by introducing the PROGRESSIVE Practice sequences and included further standing poses, often using walls and chairs, plus more variations of abdominal, supine and prone poses, and simple breathing awareness. Modifications of poses
H. Cox et al. / Complementary Therapies in Clinical Practice 16 (2010) 187e193 Table 1 Yoga class themes. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Sukkha e relaxation and comfort Sthita/dharana e steadiness of body mind and breath Asana e posture and symmetry Svadhyaya and sarira prajna e self observation and self knowledge Karmayoga e movement and mobility Rajas/akash e height, space and lift Prana prajna e intelligence and life Moksa/freedom e space and stretch Stira e strengthen the body and mind Sauch/sarva e holistically healthy Ananda e positivity and joy Saddhana and tapas e practice and passion. Savasana e relaxation was an important part of every class and of the students’ home practice.
were available for people who needed them. Table 1 describes the 12 weekly class themes, which encouraged patients to aim to take on board some of the useful elements of yoga philosophy. As part of the pilot study, and with the aim of continuing to a larger scale trial, we developed a manual for yoga practitioners and their students. The manual described an agreed series of yoga techniques that could be readily used by yoga teachers’, and simplified for ease and understanding so it could be practiced at home by LBP patients receiving yoga. Yoga students were each given a yoga manual and yoga mat, weekly practice handouts and encouraged to practice yoga at home, as well as taught to have better awareness of posture, movement and correct breathing. As learning yoga relaxation was a key element of the yoga intervention in this pilot trial it was agreed that a Relaxation CD would be developed and given to participants in any full-scale trial.
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Participants in both the yoga and control groups were given written advice on the management of LBP16 and both groups continued with their usual care. 2.4. Outcomes Clinical outcome measures were collected via postal questionnaires at baseline, four weeks and twelve weeks post-randomisation follow-up. The primary outcome measure was functional limitations as measured by the RDQ.18 The RDQ consists of a 24 point scale asking questions relating to the patients LBP and dysfunction on that day. The higher the score the greater the disability. The minimum clinically significant difference on the RDQ has been estimated to range between 2 and 3 points.19e21 This scale has been found to be sensitive to change, reliable and valid.19,20,22 Secondary outcome measures included: Clinical status as measured by the Aberdeen Back Pain Scale (ABPS) 23, where higher scores indicate more clinical problems; General health status measured using the SF-1224 where higher scores indicate better general health status; The EQ-5D health index; Pain self-efficacy as measured by the Pain Self-Efficacy Questionnaire (PSEQ)25 where higher scores represent greater self-efficacy, and; simple quantifying measures of the number of days (i) spent in bed due to LBP, (ii) with restricted activity attributed to LBP, and (iii) whether medication was used for LBP over the previous four weeks. 2.5. Data analysis The outcome data were analysed using SPSS Windows, version 15. Analysis of primary outcome data was intention to treat and
Patients identified by database search n = 286
Excluded Ineligible n= 32
Patients returned forms and assessed for eligibility n = 52
Total number of patients randomised n = 20
Randomised to Yoga n = 10 Attended no classes n = 5 Attended two classes n = 2 Attended four classes n = 2 Attended five classes n = 1
Randomised to Usual Care n = 10
Returned baseline data n = 6 (60%)
Returned baseline data n = 9 (90%)
Followed up at 4 weeks n = 5 (50%)
Followed up at 4 weeks n = 8 (80%)
Followed up at 12 weeks n = 6 (60%)
Followed up at 12 weeks n = 9 (90%)
Withdrawn n=1
Withdrawn n=0
Fig. 1. Patients’ progress through the trial.
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Table 2 Baseline characteristics of participants at randomisation. Variable
Yoga
Usual care
Total
Age (years)
N ¼ 10 39
N ¼ 10 51
N ¼ 20 45
Gender (%) Male Female
N ¼ 10 2 (20) 8 (80)
N ¼ 10 5 (50) 5 (50)
N ¼ 20 7 (35) 13 (65)
Employment status (%) Part-time Full-time Housewife Self-employed
N¼5 0 (0) 3 (60) 0 (0) 2 (40)
N¼9 1 6 1 1
(11) (67) (11) (11)
N ¼ 14 1 (7) 9 (64) 1 (7) 3 (22)
Age left education (%) 16 or below 17e19 20 or over Still in full-time education
N¼6 3 (50) 0 (0) 2 (33) 1 (17)
N¼9 6 (67) 2 (22) 1 (11) 0 (0)
N ¼ 15 9 (60) 2 (13) 3 (20) 1 (7)
Total duration of LBP (months) (range)
N ¼ 10 107.2 (10e430)
N ¼ 10 165.7 (8e486)
N ¼ 20 136.5 (8e486)
Duration of current episode (days) (range)
N¼9 56.0 (7e168)
N ¼ 10 71.0 (2e245)
N ¼ 19 63.5 (2e245)
Roland & Morris disability questionnaire (0e24 points) (SD)
N ¼ 10 9.9 (4.5)
N ¼ 10 8.7 (4.0)
N ¼ 20 9.3 (4.2)
Aberdeen back pain scale (0e100 points) (SD)
N¼6 33.5 (9.7)
N¼9 29.6 (12.8)
N ¼ 15 31.2 (11.5)
SF-12 (SD) Physical component score Mental component score
N¼6 42.6 (4.2) 41.8 (13.0)
N¼9 38.5 (9.95) 48.5 (9.1)
N ¼ 15 40.1 (8.2) 45.8 (10.9)
EQ-5D (0e1 points) (SD)
N¼6 0.71 (0.06)
N¼9 0.59 (0.26)
N ¼ 15 0.64 (0.21)
Self-efficacy (0e60 points) (SD)
N¼6 42.7 (8.5)
N¼9 44.8 (13.1)
N ¼ 15 43.9 (11.2)
Mean (range) days of usual activities missed past 4 weeks
N ¼ 10 1.0 (0e14)
N¼9 2.9 (0e10)
N ¼ 19 1.9 (0e14)
Mean no. (range) past 3 months GP visits Practice nurse visits Physiotherapist visits
N¼5 0.17 (0e1) 0.0 (0) 0.0 (0)
N¼9 1.33 (0e5) 0.11 (0e1) 0.0 (0)
N ¼ 15 0.87 (0e5) 0.07 (0e1) 0.0 (0)
No. (%) patients used medication in past 4 weeks Yes No
N ¼ 10 7.0 (70) 3.0 (30)
N ¼ 10 6.0 (60) 4.0 (40)
N ¼ 20 13.0 (65) 7.0 (35)
Patient preference (%) No. preferred yoga No. preferred usual care No. no preference
N ¼ 10 6 (60) 1 (10) 3 (30)
N ¼ 10 6 (60) 0 (0) 4 (40)
N ¼ 20 12 (60) 1 (5) 7(35)
conducted blind to treatment allocation. We estimated the effects of treatment on the outcome measures using analysis of covariance, with the change scores as the dependant variable and adjustment being made for baseline scores. 3. Results 3.1. Recruitment and follow-up The participating GP practice list size was 7040. The practice identified and mailed recruitment packs to 286 patients (4% of practice population) who had presented with LBP one or more times during the period of 1st November 2005 to 30 April 2007. Out of those 286 identified patients, 52 (18%) returned their screening forms and a total of 20 (6.9%) were eligible and randomised. The total percentage of patients randomised from the GP practice population was 0.28%.
Ineligible patients indicated any one or more of the following: less than 4 on RDQ (n ¼ 14); could not attend classes (n ¼ 1); not physically mobile (n ¼ 4); one or more red flag (n ¼ 14), indicated by (i) difficulty passing urine, (ii) numbness around rectum/genitals, (iii) numbness, pins & needles in legs, (iv) unsteadiness on feet; already taking part in yoga (n ¼ 1); In another trial for LBP (n ¼ 1); no current LBP episode (n ¼ 17), and; previous spinal surgery (n ¼ 5). Follow-up data were received in total from 15 (75%) patients at baseline, 13 (65%) at four weeks follow-up and, 15 (78%) patients at final 12 weeks follow-up from randomisation. When split by treatment, in the yoga group follow-up data were received from 6 (60%) patients at baseline, 5 (50%) at four weeks and 6 (60%) at twelve weeks, and in the usual care group data were received from 9 (90%) patients at baseline, 8 (80%) at four weeks follow-up and 9 (90%) at 12 weeks follow-up (Fig. 1). The missing data at baseline was because we screened the patients prior to randomisation, then
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sent out the baseline questionnaires to eligible patients whom we had randomised. As such this resulted in missing baseline data, and possible bias as participants knew their allocation when completing the baseline questionnaire. A full-scale trial would require us to merge the screening and baseline data into one questionnaire administrated prior to randomisation. 3.2. Baseline characteristics Table 2 shows the clinical and demographic characteristics of the patients at randomisation. The patients in the usual care group were on average 12 years older and had a greater duration of LBP and a greater duration of current episode of LBP. The majority of the patients (65%) were female, and the majority of patients were in full-time employment (60%). The mean total duration of patients’ LBP was 136.5 months, with a range of 8e486 months. The mean duration of patients’ current episode of LBP was 63.5 days, with a range of 2e245 days. Most patients when asked (60%) would have preferred to be allocated to the yoga classes.
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a different area, and one was working away and then on holiday. Two patients attended two sessions, two patients attended four sessions and one patient attended five sessions. The main reasons established for non-attendance was holidays, other reasons included childcare problems and illness. No patients allocated to the control group took part in the yoga classes. We found a relationship between those participants who were randomised to receive yoga and did not attend any classes and those patients who failed to return follow-up data and this is reflected in the imbalance in return rates between the control and intervention groups. Of the five participants who attended no classes, one returned baseline data, none returned 4-week data, and two returned 12-week data. Of the five participants who attended one or more class, all returned baseline data, all returned 4-week data, and four returned 12-week data. It is clear that there is a need to implement strategies to improve compliance for a full-scale trial. This could include a choice of times and dates of classes in each area, as in this pilot trial there was only one weekly class available. 3.4. Outcomes
3.3. Treatment retention Of the ten patients allocated to receive yoga, five (50%) did not attend any one session. Three of these could not be contacted, one withdrew immediately post-randomisation due moving to
Table 3 shows the mean change scores in outcome measures from eligibility to four weeks follow-up and twelve weeks followup. After adjustment for baseline scores, at four weeks follow-up the yoga intervention group reported greater mean decreases in
Table 3 Changes in outcome measures from baseline values in intervention and control groups at 1 month and 3 months follow-up. Yoga [N]
Usual care [N]
4 Weeks follow-up Roland & Morris disability questionnaire (0e24 points) Aberdeen back pain scale (0e100 points)
4.16 [5] 10.39 [5]
2.28 [8] 2.00 [8]
SF-12 Physical component score Mental component score
N¼5 7.35 2.49
N¼8 6.60 2.22
EQ-5D (0e1 points) Self-Efficacy (0e60 points) Mean (range) days of usual activities missed past 4 weeks
0.16 [5] 8.81 [5] 0.00
0.10 [8] 2.74 [8] 0.00
No. (%) patients used medication in past 4 weeks Yes No
N¼5 3 (60) 2 (40)
N¼8 5 (62.5) 3 (37.5)
Current LBP (%) Yes No
N¼5 3 (60) 5 (40)
N¼8 6 (75) 2 (25)
12 Weeks follow-up Roland & Morris disability questionnaire (0e24 points) Aberdeen back pain scale (0e100 points)
1.76 [6] 7.72 [4]
SF-12 Physical component score Mental component score
Mean difference (95% CI)
P value
1.88 (3.18 to 6.94) 8.39 (1.18e15.60)
0.43 0.03
0.75 (8.38 to 6.89) 4.71 (5.98 to 15.39)
0.83 0.35
0.06 (0.19 to 0.08) 6.07 (14.6 to 2.53)
0.35 0.15
2.94 [9] 5.16 [9]
1.18 (8.09 to 5.74) 2.56 (13.4 to 18.5)
0.72 0.73
N¼4 1.20 3.40
N¼9 6.88 0.59
5.68 (6.44 to 17.81) 2.81 (16.33 to 10.7)
0.32 0.65
EQ-5D (0e1 points) Self-efficacy (0e60 points)
0.06 [4] 8.26 [4]
0.04 [8] 1.22 [9]
0.02 (0.39 to 0.35) 7.04 (20.7 to 6.66)
0.89 0.28
Mean (range) days of usual activities missed past 4 weeks
N¼5 1.20 (0e6)
N¼9 1.44 (0e10)
0.24 (3.8 to 4.07)
0.89
Mean no. (range) past 3 months GP visits Practice nurse visits Physiotherapist visits
N¼5 0.60 (0e2) 0.00 (0) 0.00 (0)
N¼9 1.33 (0e4) 0.11 (0e1) 0.33 (0 to 3)
0.73 (1.03 to 2.49) 0.11 (0.21 to 0.44) 0.33 (0.66 to 1.33)
0.38 0.49 0.49
No. (%) patients used medication in past 4 weeks Yes No
N¼5 4 (80) 1 (20)
N¼9 6 (66.6) 3 (33.3)
Current LBP (%) Yes No
N¼5 4 (80) 1 (20)
N¼9 8 (89) 1 (11)
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disability as measured by the RDQ, and pain as measured by the ABPS. Although only the latter was statistically significant (P ¼ 0.03). All other variables at four weeks were not significantly different. At four weeks follow-up 80% of the yoga group had improved by at least two points on the RDQ, compared to 37.5% of the usual care group. At twelve weeks follow-up the usual care group reported a greater mean decrease in disability, and the yoga intervention group reported a greater mean decrease in pain, neither of which were significantly different. All other variables at twelve weeks were not significantly different. At twelve weeks follow-up 66.6% of the yoga group had improved by at least two points on the RDQ, compared to 55.6% of the usual care group. At both follow-up points we have observed a non-significant trend in the yoga group showing a substantial improvement in pain self-efficacy over the usual care group. 4. Discussion This pilot study provided useful data and information to inform the design of a full-scale trial of yoga for LBP. A key finding was that 18% of potentially eligible patients on the GP database consented to participate in the trial and 6.9% were deemed eligible according to the inclusion and exclusion criteria, equating to 0.28% of the total practice list size randomised. Based on this recruitment rate, the method of retrospective GP database recruitment will enable a large sample to be recruited to a full-scale trial relatively quickly in comparison to prospective recruitment methods of incident cases.26 The proposed sample size for a full-scale trial would be 280 participants and this could be met by a participating list size of approximately 100,000. Class attendance was low in this pilot trial with only 50% of trial participants randomised to receive yoga attending one or more of the classes (range 2e5). The Sherman trial9 reported a mean class attendance of 9 out of 12 classes offered which is substantially higher. The main reason for non-attendance was reported to be holidays. A likely explanation for this is that the classes were run through the six weeks of school summer holidays, as such the timing of classes should be considered carefully so as to avoid the summer break. It is usual practice for general yoga classes to take a class break at Easter, half-terms and Christmas so that participants do not have to miss class. Despite this, the fact that half of those randomised to yoga did not attend a class suggests it would be prudent to incorporate measures such as a ‘run-in’ period during which participants would attend screening visits to identify those who are unlikely to show up for future interventions, and/or to over-recruit in a full-scale trial to allow for such treatment retention issues. Another suggestion for a larger trial would be to run several yoga classes in the same area on different days of the week to allow participants the choice of a class more convenient to them, providing just one weekly class has more than likely contributed to low attendance rates. We also found differential response rates between the yoga and control group with only 60% of patients randomised to yoga returning 12-week follow-up data, compared to 90% of the control group. This is worrying as differential attrition can introduce selection bias. Secondary analysis revealed that those participants randomised to yoga and attended no classes were less likely to return follow-up questionnaires. Therefore in future trials steps should be taken to screen out participants who are not likely to attend yoga classes and therefore are less likely to return follow-up data if they are randomised to receive yoga. This might be achieved by ensuring that everyone who has consented to participate is fully aware of the trial conditions pre-randomisation. Additionally, telephone reminders, emails, and/or text message reminders could
be used to try to increase response rate. The datasets for those participants who did return their questionnaires were complete indicating that the questionnaires were appropriate and relevant to the participants . However psychological outcome measures were not collected and should be incorporated in any future trial as there is evidence of potentially beneficial effects of yoga interventions on depressive disorders.27 Clinical outcomes revealed very few statistically significant differences between groups and at twelve weeks follow-up both groups had improved to a similar degree in all clinical outcomes. However emphasis should not be placed on this outcome data as a larger sample would be needed to detect significant changes in outcomes. In view of the low attendance and differential response rate its hard to fully interpret the clinical outcome data for such a small sample. The pragmatic design of the trial was considered appropriate, and overall in terms of generalisability the broad inclusion criteria for recruiting patients made it more likely that the patients entered into the trial were fairly representative of those typically presenting in primary care with LBP. It should be noted that the trial recruited participants from the York area which is a predominantly a white, middle class population and therefore the recruitment figures might be different in other geographical and demographic areas of the country. The database recruitment process used in this pilot study can be considered as successful. Patients were identified and recruited simply and in a short space of time. This study did not find evidence for the clinical effectiveness of yoga for CLBP due to inadequate power. However the study did not primarily set out to establish the efficacy of yoga for CLBP as its main aim; rather it was to establish methodological issues that might present in a full-scale trial. As such the results of this pilot have provided information of importance for future research in this area as well as useful data and key features to inform the development of a future full-scale trial. Finally, since we conducted this pilot study funding has been awarded for a full-scale multicentre RCT from Arthritis Research UK (formerly Arthritis Research Campaign). We have addressed many of the methodological flaws discussed in this paper, and implemented many of the considerations. Although the outcome results are not yet available in the public domain, we can state that in the yoga intervention, on average nine out of the twelve classes were attended, which is comparable to the Sherman trial.9 Acknowledgements We thank the GP practice Dr. Kemp & Partners and Dr. Rebecca Field who participated in this study. This study was funded by York Trials Unit, University of York. References 1. Andersson GBJ. The epidemiology of spinal disorders. In: Frymoyer JW, editor. The adult spine: principles and practice. Philadelphia: Lippincott-Raven; 1997. p. 93e141. 2. Picavet HSJ, Schouten J, Smit HA. Prevalences and consequences of low back pain in the MORGEN-project 1993e1995. Bilthoven, Netherlands: Rijksinstituut voor Volksgezondheid en Milieu; 1996. 263200004. 3. The prevalence of back pain in Great Britain. UK Department of Health; 1998. 4. Waddell G, Feder G, McIntosh A, Lewis M, Hutchinson A. Low back pain evidence review. London: Royal College of General Practitioners; 1996. 5. UK BEAM Investigators. United Kingdom back pain exercise and manipulation (UK BEAM) randomised trial: effectiveness of physical treatments for back pain in primary care. BMJ 2004;329:1377e84. 6. Hayden JA, van Tulder MW, Malmivaara A, Koes BW. Exercise therapy for treatment of non-specific low back pain. The Cochrane Database of Systematic Reviews; 2005;. doi:10.1002/14651858. Issue 3. Art. No.: CD000335, CD000335, pub2. 7. Van Tulder MW, Koes BW. Low back pain: chronic, Clinical evidence. London: BMJ Publishing Group; 2006.
H. Cox et al. / Complementary Therapies in Clinical Practice 16 (2010) 187e193 8. Koes BW, van Tulder MW, Thomas S. Diagnosis and treatment of low back pain. BMJ 2006;332:1430e4. 9. Sherman KJ, Cherkin DC, Erro J, Miglioretti DL, Deyo RA. Comparing yoga, exercise, and a self-care book for chronic low back pain: a randomised controlled trial. Annals of Internal Medicine 2005;143:849e56. 10. Williams KA, Petronis J, Smith D, Goodrich D, Wu J, Ravi N, et al. Pain 2005;115:107e17. 11. Williams KA, Abildso C, Epstein B, Smith D, Hobbs G, Gross R, et al. Evaluation of the effectiveness and efficacy of iyengar yoga therapy on chronic low back pain. Spine 2009;34(19):2066e76. 12. Tekur P, Singphow C, Nagendra HR, Raghuram N. Effect of a short-term intensive ypga programme on pain, functional disability, and spinal flexibility in chronic low back pain: a randomised control study. Journal of Alternative and Complementary Medicine 2008;14(6):637e44. 13. Galantino ML, Bzdewka TM, Eissler-Russo JL, Holbrook ML, Mogck EP, et al. The impact of modified hatha yoga on chronic low back pain: a pilot study. Alternative Therapies in Health and Medicine 2004;10(2):56e9. 14. Saper R, Sherman K, Cullum-Dugan D, Davis R, Phillips R, Culpepper L. Yoga for chronic low back pain in a predominantly minority population: a pilot randomised controlled trial. Alternative Therapies 2009;16(6):18e27. 15. Williams K, Petronis J, Smith D, Goodrich D, Wu J, Ravi N, et al. Effect of Iyengar yoga therapy for chronic low back pain. Pain 2005;115:107e17. 16. The back book. London: TSO; 2007. 17. Iyengar BKS. Light on yoga. New York: Schocken Books; 1976. 18. Roland M, Morris R. A study of the natural history of back pain. Part I: development of a reliable and sensitive measure of disability in low back pain. Spine 1983;8:141e4.
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19. Patrick DL, Deyo RA, Atlas SJ, Singer DE, Chapin A, Keller RB. Assessing healthrelated quality of life in patients with sciatica. Spine 1995;20:1899e908. 20. Roland M, Fairbank J. The RolandeMorris disability questionnaire and the Oswestry disability questionnaire. Spine 2000;25:3115e24. 21. Bombardier C, Hayden J, Beaton DE. Minimal clinically important difference. Low back pain: outcome measures. Journal of Rheumatology 2001;28:431e8. 22. Deyo RA. Measuring the functional status of patients with low back pain. Archives of Physical Medicine and Rehabilitation 1988;69:1044e53. 23. Ruta DA, Garratt AM, Wardlaw D. Developing a valid and reliable measure of health outcome for patients with low back pain. Spine 1994;19:1887e96. 24. Jenkinson C, Layte R. Development and testing of the UK SF-12. Journal of Health Services Research and Policy 1997;2:14e8. 25. Nicholas MK. Paper presented at the annual conference of the British Psychological Society, St. Andrews; 1989. 26. McCarney R, Fisher P, van Haselen R. Accruing large numbers of patients in primary care trials by retrospective recruitment methods. Complementary Therapies in Medicine 2002;10(2):63e8. 27. Pilkington K, Kirkwood G, Rampes H, Richardson J. Yoga for depression: the research evidence. Journal of Affective Disorder 2005;89(1e3):13e24.
Other references 28. Trial website, www.yogatrial.co.uk. 29. Iyengar Yoga Association UK (IYAUK), www.iyengaryoga.org.uk. 30. British Wheel of Yoga (BWY), www.bwy.org.uk.
Contents lists available at ScienceDirect
Complementary Therapies in Clinical Practice journal homepage: www.elsevier.com/locate/ctnm
A randomised controlled trial of yoga for the treatment of chronic low back pain: Results of a pilot studyq Helen Cox a, *, Helen Tilbrook a, John Aplin b, Anna Semlyen c, David Torgerson a, Alison Trewhela d, Ian Watt a a
Department of Health Sciences, SRB Area 4, University of York, York YO10 5DD, United Kingdom Division of Human Development, St Mary’s Hospital, Manchester, United Kingdom British Wheel of Yoga Teacher, Friends Meeting House, Friargate, York, United Kingdom d Iyengar Yoga Teacher, ZedShed, Jubilee Wharf, Penryn, United Kingdom b c
a b s t r a c t Keywords: Pilot study Feasibility RCT Yoga Low back pain Primary care
Objective: To conduct a pilot trial of yoga for the treatment of chronic low back pain (LBP) to inform the feasibility and practicality of conducting a full-scale trial in the UK; and to assess the efficacy of yoga for the treatment of chronic low back pain. Design: A pragmatic randomised controlled trial was undertaken comparing yoga to usual care. Participants: Twenty participants who had presented to their GP with chronic low back pain in the previous 18 months were recruited via GP records from one practice in York, UK. Interventions: Twenty patients were randomised to either 12 weekly 75-min sessions of specialised yoga plus written advice, or usual care plus written advice. Allocation was 50/50. Main outcome measures: Recruitment rate, levels of intervention attendance, and loss to follow-up were the main non-clinical outcomes. Change as measured by the Roland and Morris disability questionnaire was the primary clinical outcome. Changes in the Aberdeen back pain scale, SF-12, EQ-5D, and pain selfefficacy were secondary clinical outcomes. Data were collected via postal questionnaire at baseline, 4 weeks, and 12 weeks follow-up. Results: Of the 286 patients identified from the GP database, 52 (18%) consented and returned the eligibility questionnaire, out of these 20 (6.9%) were eligible and randomised. The total percentage of patients randomised from the GP practice population was 0.28%. Ten patients were randomised to yoga, receiving an average of 1.7 sessions (range 0e5), and 10 were randomised to usual care. At 12 weeks follow-up data was received from 60% of patients in the yoga group and 90% of patients in the usual care group (75% overall). No significant differences were seen between groups in clinical outcomes apart from on the Aberdeen back pain scale at four weeks follow-up where the yoga group reported significantly less pain. Conclusion: This pilot study provided useful data and information to inform the design and development of a full-scale trial of yoga for CLBP in the UK. A key finding is the calculation of GP practice total list size required for patient recruitment in a full-scale trial, and the need to implement methods to increase class attendance. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Most people will experience at least one episode of low back pain (LBP) during their life and in developed countries the reported
q This study was funded by York Trials Unit, Department of Health Sciences, University of York. * Corresponding author. Tel.: þ44 01904 321614; fax: þ44 01904 321387. E-mail address: [email protected] (H. Cox). 1744-3881/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ctcp.2010.05.007
lifetime prevalence varies from 49% to 70% with point prevalences from 12% to 30%.1,2 In 1998 the UK Department of Health (DoH) presented results prepared by the Government Statistical Service on the prevalence of LBP in the UK and reported that 40% of adults said they had suffered from LBP lasting more than one day in the previous 12 months, with 15% of LBP sufferers reporting chronic pain throughout the year. Nearly 40% of LBP sufferers consulted a GP for help; 10% visited a practitioner of complementary medicine (osteopaths, chiropractors and acupuncturists); and 5% of LBP sufferers aged 16e64 in employment had taken time off work
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during the previous month because of LBP.3 More than 1000 randomised controlled trials (RCTs) have been published evaluating all types of conservative, complementary, or surgical treatments for LBP. Current evidence based guidelines for the management of LBP suggest that exercise and keeping mobile is helpful.4 However, evidence from RCTs are mixed and many have shown that exercise treatment, though widely used and recommended, has shown only a small and short-term effect on LBP.5,6 Unfortunately many commonly used interventions for LBP lack sufficient evidence for clinically relevant long-term effects,7,8 and patients are generally unsatisfied with current levels of care, hence the need for further rigorous research to seek alternative methods of reducing LBP and increasing mobility in those with back problems. Yoga is an increasingly popular therapy which offers a combination of physical exercise with mental focus that may make it a suitable therapy for the treatment of LBP. The practice of yoga focuses on the control of muscle functions using a sequence of postures. Progression through the sequence and meditation is intended to challenge muscle strength, joint flexibility and balance. Yoga is potentially a very cost effective treatment as it can be delivered in group sessions. The potential for yoga to have a longer term influence is more likely than, for example, manipulation and exercise therapy, as yoga participants will be encouraged to practice the technique at home, between classes, and to continue with home practice after the classes have been completed. A systematic review of the literature revealed four full-scale RCTs9e12 and three pilot RCTs13e15 of yoga for LBP. Although results were mixed, all four of the full-scale trials showed statistically significant effects on LBP that favoured the yoga group. For example, Sherman et al.9 reported differences in disability at 3 months and 6 months follow-up, Williams et al.10 reported reductions in pain, functional disability and medication use at 3 months follow-up, Williams et al.11 reported a reduction in disability, pain and depression at 6 months follow-up, and Tekur et al.12 reported a reduction in disability post-intervention. However these trials were limited in that they were small, in some cases interventions were delivered by only one teacher resulting in lack of generalisibility, the clinical significance of the some of the studies is questionable, and duration of follow-up was short resulting in a lack of information regarding the possible longer term benefits of yoga. Of the three pilot trials two reported a significant improvements in the yoga group. Saper et al.14 reported a reduction in pain and medication use, and Williams et al.15 reported a reduction in functional disability and pain. The results from the above trials are promising, however all of the studies above were conducted outside of the United Kingdom (UK), mainly in the USA, follow-up did not exceed 6 months, and patients were recruited by self-referral. The health care system in the UK differs greatly to that of the USA and, as far as we are aware, a study of this kind has not been conducted in the UK. For these reasons further research into designing and executing a large RCT of yoga for LBP in the UK is warranted. The primary objective of this pilot study was to focus on establishing key design features, practicality and feasibility to inform a larger multicentre trial of the effectiveness of yoga for CLBP. This study was not powered to reach statistical or clinical significance. In particular we aimed to establish the potential recruitment rate, questionnaire design, levels of intervention attendance, and loss to follow-up. 2. Methods 2.1. Study design and setting This pilot RCT compared a 12 week course of specialised yoga back classes with usual care alone and was undertaken between
June and September 2007. The yoga group continued with their usual care and both groups received written information on how to manage their LBP in the form of a small booklet called The Back Book.16 Participants were recruited and randomised from one general practice in York, UK. 2.2. Recruitment and participants The practice manager searched their database using Read Codes to identify patients who had presented to their GP with LBP once or more within the previous 18 months. The GP practice excluded pregnant patients and patients under 18 or over 65 years of age. Identified patients were mailed out a recruitment pack from the GP practice containing an information sheet, consent forms, and a screening questionnaire. Patients who were interested in participating completed the pre-randomisation screening questionnaire and consent form and returned them to the University of York where their eligibility was assessed. The inclusion criteria were: aged 18e65 years; a score of 4 or more on the Roland and Morris Disability Scale (RDQ); had presented to their GP in the previous 18 months with LBP; can attend yoga classes (times and dates), and; sufficiently physically mobile (i.e. can get up off the floor unaided, and can walk up and down stairs). The exclusion criteria were: pregnant women; psychosis or recent substance abuse; already participating in yoga; already in a trial for their LBP; not currently suffering an episode of LBP; previous spinal surgery, and; clinical indications of serious spinal or neurological pathology as indicated by four ‘red flags’ (1) difficulty passing or controlling urine, (2) numbness around back passage or inner thighs, (3) numbness, pins and needles or weakness in both legs, and (4) unsteadiness on feet. All of this data was collected via the initial screening questionnaire. The details of those patients who were eligible to participate were then sent to their GP who second checked their eligibility against the patient’s records. Patients were then randomised using computer generated random numbers by an independent data manager to either 12 weekly classes of yoga or usual care. York Local Research Ethics Committee approved the study. 2.3. Interventions The yoga intervention consisted of 12 weekly 75-min classes and was devised by an Iyengar Yoga teacher (IYAUK) and LBP yoga specialist, in collaboration with a British Wheel of Yoga teacher (BWY), who delivered the intervention. The structure was based on that previously used in the US Karen Sherman yoga trial,9 whilst ensuring that a common ground was found between the two associations of IYAUK and BWY. Other influences included Geeta and B.K.S. Iyengar, who has taught yoga for over 70 years and has applied therapeutic variations of classical poses to many health problems including LBP.17 The yoga programme was introduced in a gentle graded way over the 12 weeks. Class 1 focused on relaxation and pain-relieving postures. Classes 2e6 taught the CORE practice sequences, which included settling/pacifying poses, standing poses to teach good posture, improve flexibility in the upper back and shoulders, then chair-seated posture-strengthening poses. These were followed by simple supine and prone floor poses, to give strength, mobility and further postural understanding and to allow the students to learn a good grounding in the fundamental starting points of the majority of yoga pose types. Classes 7e12 built upon the CORE Practices poses, by introducing the PROGRESSIVE Practice sequences and included further standing poses, often using walls and chairs, plus more variations of abdominal, supine and prone poses, and simple breathing awareness. Modifications of poses
H. Cox et al. / Complementary Therapies in Clinical Practice 16 (2010) 187e193 Table 1 Yoga class themes. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Sukkha e relaxation and comfort Sthita/dharana e steadiness of body mind and breath Asana e posture and symmetry Svadhyaya and sarira prajna e self observation and self knowledge Karmayoga e movement and mobility Rajas/akash e height, space and lift Prana prajna e intelligence and life Moksa/freedom e space and stretch Stira e strengthen the body and mind Sauch/sarva e holistically healthy Ananda e positivity and joy Saddhana and tapas e practice and passion. Savasana e relaxation was an important part of every class and of the students’ home practice.
were available for people who needed them. Table 1 describes the 12 weekly class themes, which encouraged patients to aim to take on board some of the useful elements of yoga philosophy. As part of the pilot study, and with the aim of continuing to a larger scale trial, we developed a manual for yoga practitioners and their students. The manual described an agreed series of yoga techniques that could be readily used by yoga teachers’, and simplified for ease and understanding so it could be practiced at home by LBP patients receiving yoga. Yoga students were each given a yoga manual and yoga mat, weekly practice handouts and encouraged to practice yoga at home, as well as taught to have better awareness of posture, movement and correct breathing. As learning yoga relaxation was a key element of the yoga intervention in this pilot trial it was agreed that a Relaxation CD would be developed and given to participants in any full-scale trial.
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Participants in both the yoga and control groups were given written advice on the management of LBP16 and both groups continued with their usual care. 2.4. Outcomes Clinical outcome measures were collected via postal questionnaires at baseline, four weeks and twelve weeks post-randomisation follow-up. The primary outcome measure was functional limitations as measured by the RDQ.18 The RDQ consists of a 24 point scale asking questions relating to the patients LBP and dysfunction on that day. The higher the score the greater the disability. The minimum clinically significant difference on the RDQ has been estimated to range between 2 and 3 points.19e21 This scale has been found to be sensitive to change, reliable and valid.19,20,22 Secondary outcome measures included: Clinical status as measured by the Aberdeen Back Pain Scale (ABPS) 23, where higher scores indicate more clinical problems; General health status measured using the SF-1224 where higher scores indicate better general health status; The EQ-5D health index; Pain self-efficacy as measured by the Pain Self-Efficacy Questionnaire (PSEQ)25 where higher scores represent greater self-efficacy, and; simple quantifying measures of the number of days (i) spent in bed due to LBP, (ii) with restricted activity attributed to LBP, and (iii) whether medication was used for LBP over the previous four weeks. 2.5. Data analysis The outcome data were analysed using SPSS Windows, version 15. Analysis of primary outcome data was intention to treat and
Patients identified by database search n = 286
Excluded Ineligible n= 32
Patients returned forms and assessed for eligibility n = 52
Total number of patients randomised n = 20
Randomised to Yoga n = 10 Attended no classes n = 5 Attended two classes n = 2 Attended four classes n = 2 Attended five classes n = 1
Randomised to Usual Care n = 10
Returned baseline data n = 6 (60%)
Returned baseline data n = 9 (90%)
Followed up at 4 weeks n = 5 (50%)
Followed up at 4 weeks n = 8 (80%)
Followed up at 12 weeks n = 6 (60%)
Followed up at 12 weeks n = 9 (90%)
Withdrawn n=1
Withdrawn n=0
Fig. 1. Patients’ progress through the trial.
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Table 2 Baseline characteristics of participants at randomisation. Variable
Yoga
Usual care
Total
Age (years)
N ¼ 10 39
N ¼ 10 51
N ¼ 20 45
Gender (%) Male Female
N ¼ 10 2 (20) 8 (80)
N ¼ 10 5 (50) 5 (50)
N ¼ 20 7 (35) 13 (65)
Employment status (%) Part-time Full-time Housewife Self-employed
N¼5 0 (0) 3 (60) 0 (0) 2 (40)
N¼9 1 6 1 1
(11) (67) (11) (11)
N ¼ 14 1 (7) 9 (64) 1 (7) 3 (22)
Age left education (%) 16 or below 17e19 20 or over Still in full-time education
N¼6 3 (50) 0 (0) 2 (33) 1 (17)
N¼9 6 (67) 2 (22) 1 (11) 0 (0)
N ¼ 15 9 (60) 2 (13) 3 (20) 1 (7)
Total duration of LBP (months) (range)
N ¼ 10 107.2 (10e430)
N ¼ 10 165.7 (8e486)
N ¼ 20 136.5 (8e486)
Duration of current episode (days) (range)
N¼9 56.0 (7e168)
N ¼ 10 71.0 (2e245)
N ¼ 19 63.5 (2e245)
Roland & Morris disability questionnaire (0e24 points) (SD)
N ¼ 10 9.9 (4.5)
N ¼ 10 8.7 (4.0)
N ¼ 20 9.3 (4.2)
Aberdeen back pain scale (0e100 points) (SD)
N¼6 33.5 (9.7)
N¼9 29.6 (12.8)
N ¼ 15 31.2 (11.5)
SF-12 (SD) Physical component score Mental component score
N¼6 42.6 (4.2) 41.8 (13.0)
N¼9 38.5 (9.95) 48.5 (9.1)
N ¼ 15 40.1 (8.2) 45.8 (10.9)
EQ-5D (0e1 points) (SD)
N¼6 0.71 (0.06)
N¼9 0.59 (0.26)
N ¼ 15 0.64 (0.21)
Self-efficacy (0e60 points) (SD)
N¼6 42.7 (8.5)
N¼9 44.8 (13.1)
N ¼ 15 43.9 (11.2)
Mean (range) days of usual activities missed past 4 weeks
N ¼ 10 1.0 (0e14)
N¼9 2.9 (0e10)
N ¼ 19 1.9 (0e14)
Mean no. (range) past 3 months GP visits Practice nurse visits Physiotherapist visits
N¼5 0.17 (0e1) 0.0 (0) 0.0 (0)
N¼9 1.33 (0e5) 0.11 (0e1) 0.0 (0)
N ¼ 15 0.87 (0e5) 0.07 (0e1) 0.0 (0)
No. (%) patients used medication in past 4 weeks Yes No
N ¼ 10 7.0 (70) 3.0 (30)
N ¼ 10 6.0 (60) 4.0 (40)
N ¼ 20 13.0 (65) 7.0 (35)
Patient preference (%) No. preferred yoga No. preferred usual care No. no preference
N ¼ 10 6 (60) 1 (10) 3 (30)
N ¼ 10 6 (60) 0 (0) 4 (40)
N ¼ 20 12 (60) 1 (5) 7(35)
conducted blind to treatment allocation. We estimated the effects of treatment on the outcome measures using analysis of covariance, with the change scores as the dependant variable and adjustment being made for baseline scores. 3. Results 3.1. Recruitment and follow-up The participating GP practice list size was 7040. The practice identified and mailed recruitment packs to 286 patients (4% of practice population) who had presented with LBP one or more times during the period of 1st November 2005 to 30 April 2007. Out of those 286 identified patients, 52 (18%) returned their screening forms and a total of 20 (6.9%) were eligible and randomised. The total percentage of patients randomised from the GP practice population was 0.28%.
Ineligible patients indicated any one or more of the following: less than 4 on RDQ (n ¼ 14); could not attend classes (n ¼ 1); not physically mobile (n ¼ 4); one or more red flag (n ¼ 14), indicated by (i) difficulty passing urine, (ii) numbness around rectum/genitals, (iii) numbness, pins & needles in legs, (iv) unsteadiness on feet; already taking part in yoga (n ¼ 1); In another trial for LBP (n ¼ 1); no current LBP episode (n ¼ 17), and; previous spinal surgery (n ¼ 5). Follow-up data were received in total from 15 (75%) patients at baseline, 13 (65%) at four weeks follow-up and, 15 (78%) patients at final 12 weeks follow-up from randomisation. When split by treatment, in the yoga group follow-up data were received from 6 (60%) patients at baseline, 5 (50%) at four weeks and 6 (60%) at twelve weeks, and in the usual care group data were received from 9 (90%) patients at baseline, 8 (80%) at four weeks follow-up and 9 (90%) at 12 weeks follow-up (Fig. 1). The missing data at baseline was because we screened the patients prior to randomisation, then
H. Cox et al. / Complementary Therapies in Clinical Practice 16 (2010) 187e193
sent out the baseline questionnaires to eligible patients whom we had randomised. As such this resulted in missing baseline data, and possible bias as participants knew their allocation when completing the baseline questionnaire. A full-scale trial would require us to merge the screening and baseline data into one questionnaire administrated prior to randomisation. 3.2. Baseline characteristics Table 2 shows the clinical and demographic characteristics of the patients at randomisation. The patients in the usual care group were on average 12 years older and had a greater duration of LBP and a greater duration of current episode of LBP. The majority of the patients (65%) were female, and the majority of patients were in full-time employment (60%). The mean total duration of patients’ LBP was 136.5 months, with a range of 8e486 months. The mean duration of patients’ current episode of LBP was 63.5 days, with a range of 2e245 days. Most patients when asked (60%) would have preferred to be allocated to the yoga classes.
191
a different area, and one was working away and then on holiday. Two patients attended two sessions, two patients attended four sessions and one patient attended five sessions. The main reasons established for non-attendance was holidays, other reasons included childcare problems and illness. No patients allocated to the control group took part in the yoga classes. We found a relationship between those participants who were randomised to receive yoga and did not attend any classes and those patients who failed to return follow-up data and this is reflected in the imbalance in return rates between the control and intervention groups. Of the five participants who attended no classes, one returned baseline data, none returned 4-week data, and two returned 12-week data. Of the five participants who attended one or more class, all returned baseline data, all returned 4-week data, and four returned 12-week data. It is clear that there is a need to implement strategies to improve compliance for a full-scale trial. This could include a choice of times and dates of classes in each area, as in this pilot trial there was only one weekly class available. 3.4. Outcomes
3.3. Treatment retention Of the ten patients allocated to receive yoga, five (50%) did not attend any one session. Three of these could not be contacted, one withdrew immediately post-randomisation due moving to
Table 3 shows the mean change scores in outcome measures from eligibility to four weeks follow-up and twelve weeks followup. After adjustment for baseline scores, at four weeks follow-up the yoga intervention group reported greater mean decreases in
Table 3 Changes in outcome measures from baseline values in intervention and control groups at 1 month and 3 months follow-up. Yoga [N]
Usual care [N]
4 Weeks follow-up Roland & Morris disability questionnaire (0e24 points) Aberdeen back pain scale (0e100 points)
4.16 [5] 10.39 [5]
2.28 [8] 2.00 [8]
SF-12 Physical component score Mental component score
N¼5 7.35 2.49
N¼8 6.60 2.22
EQ-5D (0e1 points) Self-Efficacy (0e60 points) Mean (range) days of usual activities missed past 4 weeks
0.16 [5] 8.81 [5] 0.00
0.10 [8] 2.74 [8] 0.00
No. (%) patients used medication in past 4 weeks Yes No
N¼5 3 (60) 2 (40)
N¼8 5 (62.5) 3 (37.5)
Current LBP (%) Yes No
N¼5 3 (60) 5 (40)
N¼8 6 (75) 2 (25)
12 Weeks follow-up Roland & Morris disability questionnaire (0e24 points) Aberdeen back pain scale (0e100 points)
1.76 [6] 7.72 [4]
SF-12 Physical component score Mental component score
Mean difference (95% CI)
P value
1.88 (3.18 to 6.94) 8.39 (1.18e15.60)
0.43 0.03
0.75 (8.38 to 6.89) 4.71 (5.98 to 15.39)
0.83 0.35
0.06 (0.19 to 0.08) 6.07 (14.6 to 2.53)
0.35 0.15
2.94 [9] 5.16 [9]
1.18 (8.09 to 5.74) 2.56 (13.4 to 18.5)
0.72 0.73
N¼4 1.20 3.40
N¼9 6.88 0.59
5.68 (6.44 to 17.81) 2.81 (16.33 to 10.7)
0.32 0.65
EQ-5D (0e1 points) Self-efficacy (0e60 points)
0.06 [4] 8.26 [4]
0.04 [8] 1.22 [9]
0.02 (0.39 to 0.35) 7.04 (20.7 to 6.66)
0.89 0.28
Mean (range) days of usual activities missed past 4 weeks
N¼5 1.20 (0e6)
N¼9 1.44 (0e10)
0.24 (3.8 to 4.07)
0.89
Mean no. (range) past 3 months GP visits Practice nurse visits Physiotherapist visits
N¼5 0.60 (0e2) 0.00 (0) 0.00 (0)
N¼9 1.33 (0e4) 0.11 (0e1) 0.33 (0 to 3)
0.73 (1.03 to 2.49) 0.11 (0.21 to 0.44) 0.33 (0.66 to 1.33)
0.38 0.49 0.49
No. (%) patients used medication in past 4 weeks Yes No
N¼5 4 (80) 1 (20)
N¼9 6 (66.6) 3 (33.3)
Current LBP (%) Yes No
N¼5 4 (80) 1 (20)
N¼9 8 (89) 1 (11)
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disability as measured by the RDQ, and pain as measured by the ABPS. Although only the latter was statistically significant (P ¼ 0.03). All other variables at four weeks were not significantly different. At four weeks follow-up 80% of the yoga group had improved by at least two points on the RDQ, compared to 37.5% of the usual care group. At twelve weeks follow-up the usual care group reported a greater mean decrease in disability, and the yoga intervention group reported a greater mean decrease in pain, neither of which were significantly different. All other variables at twelve weeks were not significantly different. At twelve weeks follow-up 66.6% of the yoga group had improved by at least two points on the RDQ, compared to 55.6% of the usual care group. At both follow-up points we have observed a non-significant trend in the yoga group showing a substantial improvement in pain self-efficacy over the usual care group. 4. Discussion This pilot study provided useful data and information to inform the design of a full-scale trial of yoga for LBP. A key finding was that 18% of potentially eligible patients on the GP database consented to participate in the trial and 6.9% were deemed eligible according to the inclusion and exclusion criteria, equating to 0.28% of the total practice list size randomised. Based on this recruitment rate, the method of retrospective GP database recruitment will enable a large sample to be recruited to a full-scale trial relatively quickly in comparison to prospective recruitment methods of incident cases.26 The proposed sample size for a full-scale trial would be 280 participants and this could be met by a participating list size of approximately 100,000. Class attendance was low in this pilot trial with only 50% of trial participants randomised to receive yoga attending one or more of the classes (range 2e5). The Sherman trial9 reported a mean class attendance of 9 out of 12 classes offered which is substantially higher. The main reason for non-attendance was reported to be holidays. A likely explanation for this is that the classes were run through the six weeks of school summer holidays, as such the timing of classes should be considered carefully so as to avoid the summer break. It is usual practice for general yoga classes to take a class break at Easter, half-terms and Christmas so that participants do not have to miss class. Despite this, the fact that half of those randomised to yoga did not attend a class suggests it would be prudent to incorporate measures such as a ‘run-in’ period during which participants would attend screening visits to identify those who are unlikely to show up for future interventions, and/or to over-recruit in a full-scale trial to allow for such treatment retention issues. Another suggestion for a larger trial would be to run several yoga classes in the same area on different days of the week to allow participants the choice of a class more convenient to them, providing just one weekly class has more than likely contributed to low attendance rates. We also found differential response rates between the yoga and control group with only 60% of patients randomised to yoga returning 12-week follow-up data, compared to 90% of the control group. This is worrying as differential attrition can introduce selection bias. Secondary analysis revealed that those participants randomised to yoga and attended no classes were less likely to return follow-up questionnaires. Therefore in future trials steps should be taken to screen out participants who are not likely to attend yoga classes and therefore are less likely to return follow-up data if they are randomised to receive yoga. This might be achieved by ensuring that everyone who has consented to participate is fully aware of the trial conditions pre-randomisation. Additionally, telephone reminders, emails, and/or text message reminders could
be used to try to increase response rate. The datasets for those participants who did return their questionnaires were complete indicating that the questionnaires were appropriate and relevant to the participants . However psychological outcome measures were not collected and should be incorporated in any future trial as there is evidence of potentially beneficial effects of yoga interventions on depressive disorders.27 Clinical outcomes revealed very few statistically significant differences between groups and at twelve weeks follow-up both groups had improved to a similar degree in all clinical outcomes. However emphasis should not be placed on this outcome data as a larger sample would be needed to detect significant changes in outcomes. In view of the low attendance and differential response rate its hard to fully interpret the clinical outcome data for such a small sample. The pragmatic design of the trial was considered appropriate, and overall in terms of generalisability the broad inclusion criteria for recruiting patients made it more likely that the patients entered into the trial were fairly representative of those typically presenting in primary care with LBP. It should be noted that the trial recruited participants from the York area which is a predominantly a white, middle class population and therefore the recruitment figures might be different in other geographical and demographic areas of the country. The database recruitment process used in this pilot study can be considered as successful. Patients were identified and recruited simply and in a short space of time. This study did not find evidence for the clinical effectiveness of yoga for CLBP due to inadequate power. However the study did not primarily set out to establish the efficacy of yoga for CLBP as its main aim; rather it was to establish methodological issues that might present in a full-scale trial. As such the results of this pilot have provided information of importance for future research in this area as well as useful data and key features to inform the development of a future full-scale trial. Finally, since we conducted this pilot study funding has been awarded for a full-scale multicentre RCT from Arthritis Research UK (formerly Arthritis Research Campaign). We have addressed many of the methodological flaws discussed in this paper, and implemented many of the considerations. Although the outcome results are not yet available in the public domain, we can state that in the yoga intervention, on average nine out of the twelve classes were attended, which is comparable to the Sherman trial.9 Acknowledgements We thank the GP practice Dr. Kemp & Partners and Dr. Rebecca Field who participated in this study. This study was funded by York Trials Unit, University of York. References 1. Andersson GBJ. The epidemiology of spinal disorders. In: Frymoyer JW, editor. The adult spine: principles and practice. Philadelphia: Lippincott-Raven; 1997. p. 93e141. 2. Picavet HSJ, Schouten J, Smit HA. Prevalences and consequences of low back pain in the MORGEN-project 1993e1995. Bilthoven, Netherlands: Rijksinstituut voor Volksgezondheid en Milieu; 1996. 263200004. 3. The prevalence of back pain in Great Britain. UK Department of Health; 1998. 4. Waddell G, Feder G, McIntosh A, Lewis M, Hutchinson A. Low back pain evidence review. London: Royal College of General Practitioners; 1996. 5. UK BEAM Investigators. United Kingdom back pain exercise and manipulation (UK BEAM) randomised trial: effectiveness of physical treatments for back pain in primary care. BMJ 2004;329:1377e84. 6. Hayden JA, van Tulder MW, Malmivaara A, Koes BW. Exercise therapy for treatment of non-specific low back pain. The Cochrane Database of Systematic Reviews; 2005;. doi:10.1002/14651858. Issue 3. Art. No.: CD000335, CD000335, pub2. 7. Van Tulder MW, Koes BW. Low back pain: chronic, Clinical evidence. London: BMJ Publishing Group; 2006.
H. Cox et al. / Complementary Therapies in Clinical Practice 16 (2010) 187e193 8. Koes BW, van Tulder MW, Thomas S. Diagnosis and treatment of low back pain. BMJ 2006;332:1430e4. 9. Sherman KJ, Cherkin DC, Erro J, Miglioretti DL, Deyo RA. Comparing yoga, exercise, and a self-care book for chronic low back pain: a randomised controlled trial. Annals of Internal Medicine 2005;143:849e56. 10. Williams KA, Petronis J, Smith D, Goodrich D, Wu J, Ravi N, et al. Pain 2005;115:107e17. 11. Williams KA, Abildso C, Epstein B, Smith D, Hobbs G, Gross R, et al. Evaluation of the effectiveness and efficacy of iyengar yoga therapy on chronic low back pain. Spine 2009;34(19):2066e76. 12. Tekur P, Singphow C, Nagendra HR, Raghuram N. Effect of a short-term intensive ypga programme on pain, functional disability, and spinal flexibility in chronic low back pain: a randomised control study. Journal of Alternative and Complementary Medicine 2008;14(6):637e44. 13. Galantino ML, Bzdewka TM, Eissler-Russo JL, Holbrook ML, Mogck EP, et al. The impact of modified hatha yoga on chronic low back pain: a pilot study. Alternative Therapies in Health and Medicine 2004;10(2):56e9. 14. Saper R, Sherman K, Cullum-Dugan D, Davis R, Phillips R, Culpepper L. Yoga for chronic low back pain in a predominantly minority population: a pilot randomised controlled trial. Alternative Therapies 2009;16(6):18e27. 15. Williams K, Petronis J, Smith D, Goodrich D, Wu J, Ravi N, et al. Effect of Iyengar yoga therapy for chronic low back pain. Pain 2005;115:107e17. 16. The back book. London: TSO; 2007. 17. Iyengar BKS. Light on yoga. New York: Schocken Books; 1976. 18. Roland M, Morris R. A study of the natural history of back pain. Part I: development of a reliable and sensitive measure of disability in low back pain. Spine 1983;8:141e4.
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19. Patrick DL, Deyo RA, Atlas SJ, Singer DE, Chapin A, Keller RB. Assessing healthrelated quality of life in patients with sciatica. Spine 1995;20:1899e908. 20. Roland M, Fairbank J. The RolandeMorris disability questionnaire and the Oswestry disability questionnaire. Spine 2000;25:3115e24. 21. Bombardier C, Hayden J, Beaton DE. Minimal clinically important difference. Low back pain: outcome measures. Journal of Rheumatology 2001;28:431e8. 22. Deyo RA. Measuring the functional status of patients with low back pain. Archives of Physical Medicine and Rehabilitation 1988;69:1044e53. 23. Ruta DA, Garratt AM, Wardlaw D. Developing a valid and reliable measure of health outcome for patients with low back pain. Spine 1994;19:1887e96. 24. Jenkinson C, Layte R. Development and testing of the UK SF-12. Journal of Health Services Research and Policy 1997;2:14e8. 25. Nicholas MK. Paper presented at the annual conference of the British Psychological Society, St. Andrews; 1989. 26. McCarney R, Fisher P, van Haselen R. Accruing large numbers of patients in primary care trials by retrospective recruitment methods. Complementary Therapies in Medicine 2002;10(2):63e8. 27. Pilkington K, Kirkwood G, Rampes H, Richardson J. Yoga for depression: the research evidence. Journal of Affective Disorder 2005;89(1e3):13e24.
Other references 28. Trial website, www.yogatrial.co.uk. 29. Iyengar Yoga Association UK (IYAUK), www.iyengaryoga.org.uk. 30. British Wheel of Yoga (BWY), www.bwy.org.uk.