- Email: [email protected]
PEDro. A database of randomized trials and systematic reviews in physiotherapy
Manual Therapy (2000) 5(4), 223–226 # 2000 Harcourt Publishers Ltd doi:10.1054/math.2000.0372, available online at http://www.idealibrary.com on
Professional issue
PEDro. A database of randomized trials and systematic reviews in physiotherapy C. Sherrington* ,{, R. D. Herbert* ,{, C. G. Maher* ,{, A. M. Moseley*,} *Centre for Evidence-Based Physiotherapy, School of Physiotherapy, P.O. Box 170, Lidcombe NSW 1825, Australia. {Physiotherapy Department, Bankstown-Lidcombe Hospital, Sydney, Australia. {School of Physiotherapy, University of Sydney, Australia. }Rehabilitation Studies Unit, University of Sydney, Australia.
SUMMARY. This paper describes PEDro, the Physiotherapy Evidence Database. PEDro is a web-based database of randomized controlled trials and systematic reviews in physiotherapy. It can be accessed free of charge at http://ptwww.cchs.usyd.edu.au/pedro. The database contains bibliographic details and abstacts of most Englishlanguage randomized trials and systematic reviews in physiotherapy, and of many trials and reviews in other languages. Trials on the database are rated on the basis of their methodological quality so that users of the database can quickly identify trials of high quality. Trials and systematic reviews are extensively indexed to facilitate searching. PEDro provides an important information resource to support evidence-based clinical practice. # 2000 Harcourt Publishers Ltd.
relevant to manual therapy, and how to become involved in the PEDro initiative.
INTRODUCTION The Physiotherapy Evidence Database (PEDro) is a new database of randomised trials and systematic reviews in physiotherapy. The database, developed and maintained by the Centre for Evidence-Based Physiotherapy in Sydney, is freely available on the web. The URL is http://ptwww.cchs.usyd.edu.au/ pedro. PEDro was developed to give physiotherapists and consumers of physiotherapy services rapid access to the best available evidence of the effects of physiotherapy interventions. The best evidence of the effects of therapeutic interventions is usually considered to be provided by randomised controlled trials or by systematic reviews of randomised trials (National Health and Medical Research Council 1999). PEDro archives bibliographic details and abstracts of peer-reviewed published full reports of randomised controlled trials and systematic reviews in physiotherapy. Trials on the database are rated on the basis of their methodological quality so users can rapidly identify studies which are likely to be of the highest quality. This paper briefly describes the criteria and methods used to assemble PEDro, how PEDro can be used to find randomised trials and systematic reviews, a brief overview of the contents of PEDro
CRITERIA AND METHODS USED TO ASSEMBLE PEDro Locating trials Several methods have been used to locate the trials and systematic reviews that have been indexed on the PEDro database. The Rehabilitation and Related Therapies Field of the Cochrane Collaboration generously donated their pre-existing database of randomised trials in rehabilitation, which was combined with personal databases of the Steering Committee of the Centre for Evidence-Based Physiotherapy. This has been supplemented by optimised searches of three databases of the medical and allied health serials literature (Medline, Embase and Cinahl), a process which has now been automated. In addition, the Cochrane Database of Systematic Reviews and the Cochrane Clinical Trials Register were also searched. Each new release of these databases is also searched. Reference lists in systematic reviews on the PEDro database are checked for additional relevant publications. A large number of experts in various aspects of physiotherapy have also been contacted and many have assisted in the identification of relevant trials and reviews. Lastly,
Correspondence to: RH; E-mail: [email protected] 223
224 Manual Therapy
‘Friends of PEDro’ (volunteer physiotherapists who have assisted in the development and maintenance of the database) and users of PEDro regularly notify the Centre of trials that are not on PEDro, using a webbased notification form.
Inclusion criteria for trials Strict inclusion criteria are used to determine which studies will be indexed on PEDro. To be indexed, clinical trials must involve comparison of at least two interventions. One of these interventions could be a ‘no-treatment’ control or a ‘sham’ treatment. Alternately, the trial could involve comparisons of two interventions that are thought to be effective, with the aim of determining which is most effective. Crossover trials in which each subject is subjected to more than one intervention are included in PEDro provided the other criteria are also met. Interventions could include (but are not limited to) treatments, prevention strategies, diagnostic tests or techniques, or management or education strategies. At least one of the interventions must be currently part of physiotherapy practice or could become part of physiotherapy practice, however, the study need not be carried out by physiotherapists. Nor is it necessary that the interventions be carried out by a physiotherapist in the trial. The interventions must be applied to subjects who are representative, or who are intended to be representative, of those to whom the intervention might be applied in the course of physiotherapy practice. This usually means that the intervention is applied to people with a health condition or disability (in the case of a treatment) or at risk of developing a health condition or disability (in the case of a prevention strategy). Trials performed on animals rather than humans are not archived on PEDro. To be included in PEDro, the study must definitely have used random or intendedto-be-random allocation (intended-to-be random allocation refers to methods of allocation such as alternation or allocation by odd and even birth dates or hospital record numbers). If it is not certain that one of these methods of allocation was used the study is not included. Lastly, the paper must be a full paper, not an abstract published in a peer-reviewed journal.
Inclusion criteria for systematic reviews Systematic reviews are distinguished from traditional ‘narrative’ reviews by the use of methods to minimise bias. PEDro indexes those reviews of clinical trials in physiotherapy which contain a Methods section, and which review at least one trial which satisfies the other criteria listed above. Judgements of the quality of the methods used or whether the authors actually did what they claimed are not used to decide if a trial Manual Therapy (2000) 5(4), 223–226
or systematic review is eligible for inclusion in PEDro. Methods used to rate trial quality Each clinical trial on the PEDro database is rated on the basis of its methodological ‘quality’ using the PEDro scale. Systematic reviews are not rated. The 11-item PEDro scale is based on the 9-item Delphi list developed by Verhagen and colleagues at the Department of Epidemiology, University of Maastricht (Verhagen et al. 1998). Verhagen and colleagues used a formal method called the Delphi consensus technique to identify items that a panel of experts believed should be included in a scale of methodological quality. The purpose of the PEDro scale differs slightly from that of the Delphi list. The PEDro scale is designed to help the users of the PEDro database rapidly identify which of the randomised clinical trials indexed on the PEDro database are likely to be internally valid (items 2–9), and could have sufficient statistical information to make their results interpretable (items 10–11). One item (item 1) originally on the Delphi list has been retained on the PEDro scale so that the Delphi list is complete, but as this item relates to external validity this item is not used to calculate the PEDro score. The PEDro score is thus a score out of 10. Ideally those items on the PEDro scale designed to provide a measure of internal validity would be chosen on the basis of their demonstrated ability to predict bias. Several studies have begun to elucidate what features of study design best predict bias (e.g. Schulz et al. 1995). However, such studies are difficult to perform, not least because they need to be tested across a wide spectrum of clinical trials and they must assess very large numbers of studies to attain the necessary statistical precision; so information about predictive validity of scale items is still very incomplete. Many items on the Delphi list and the PEDro scale have been shown to predict bias in medical trials, e.g. randomization (Sacks et al. 1982; Chalmers et al. 1983; Colditz et al. 1989; Miller et al. 1989), concealment (Chalmers et al. 1983; Schulz et al. 1995; Moher et al. 1998) and blinding (Colditz et al. 1989; Schulz et al. 1995). But they are yet to be extensively validated on trials in physiotherapy. As more empirical data comes to hand it may become possible to delete those items on the PEDro scale which are not good predictors of bias, or ‘weight’ scale items so that the PEDro score reflects the importance of individual scale items. The Centre for EvidenceBased Physiotherapy is currently investigating the validity of the PEDro scale and PEDro scale items. The reliabilty of the PEDro scale has been tested (Moseley et al. 1999). The reliability of most items # 2000 Harcourt Publishers Ltd
PEDro 225
(agreement beyond chance) is moderate to high; Kappa ranged from 0.40 to 0.73, with a mean of 0.58. Total PEDro score has moderate reliability: ICC ¼ 0.54 (95% CI: 0.39–0.71). These reliability coefficients relate to judgements made by a single evaluator. To reduce error further, all trials are rated by two evaluators and when consensus is not reached they are arbitrated by a third evaluator. We caution users of PEDro that the PEDro scale should not be used as a measure of the ‘validity’ of a study’s conclusions. In particular, studies which show significant treatment effects and which score highly on the PEDro scale do not necessarily provide evidence that the treatment is clinically useful. Judgements of the clinical usefulness of a treatment must also involve consideration of whether the treatment effect was big enough to be clinically worthwhile, whether the positive effects of the treatment outweigh its negative effects, and the cost-effectiveness of the treatment. The scale should not be used to compare the ‘quality’ of trials performed across different areas of physiotherapy practice, primarily because it is not possible to satisfy all scale items in some areas of physiotherapy practice.
elbow) would be to search for trials classified as ‘stretching, mobilisation, manipulation, massage’ AND ‘elbow or forearm’. This returns 18 records, all randomised trials, of which approximately five are on manual therapy (depending on how strictly ‘manual therapy’ is defined). An alternate approach would be to type the terms ‘epicondylitis’ and ‘tennis’ in the abstract field, and combine them by clicking on ‘OR’ at the bottom of the search page. This returns 17 records, including the same 5 relevant trials. In general, searching for free words in the abstract is a more specific, and therefore more efficient, search strategy. Of the 5 relevant trials, PEDro scores ranged from 3/10 to 6/10 (two trials). Clicking on the titles returns bibliographic details and an abstract. The abstracts of the trials which scored 6/10 showed that progressive strengthening and stretching exercises were more effective at reducing pain and returning subjects to work than pulsed ultrasound, and that local cortico-steroid injections produced greater short-term reductions in symptoms than Cyriax-type manipulation. The clinician who was interested in the effects of manual therapy techniques on epicondylalgia would probably want to obtain full copies of these papers for a careful critical appraisal (see Sackett et al. 2000 for details).
FINDING TRIALS AND REVIEWS ON PEDro The PEDro database has been constructed in a way that makes it easy to search. All records on the database have been classified according to the therapy applied (e.g. ‘stretching, mobilisation, manipulation, massage’), the subdiscipline of physiotherapy (e.g. ‘musculoskeletal’), the problem being treated (e.g. ‘pain’), and the body part being treated (e.g. ‘head or neck’). Users can search for trials or systematic reviews by specifying particular classifications on any of these dimensions. Usually, however, the most efficient way to search the database is to search for free words in the abstract. If a number of search criteria are applied simultaneously they can be combined with logical/(AND or OR) operators (e.g. ‘neck AND pain’ or ‘neck OR cervical’). By default, PEDro searches for records which include search terms or any extensions of them. Thus, if the search term is ‘cervic’, PEDro will search for ‘cervical’ and ‘cervicogenic’ and any other word starting with cervic. When there are several variations of a search term (e.g. zygapophyseal, facet, facets), each variation can be included and combined with the OR operator. PEDro can be asked to search for series of words by including the series in inverted commas. Some of these principles will be illustrated by an example. One simple way to identify systematic reviews and clinical trials of the effects of manual therapy techniques for lateral epicondylitis (tennis # 2000 Harcourt Publishers Ltd
CONTENTS OF PEDro As at 28 July 2000 PEDro contained 2426 records of which 2160 were RCTs and 266 were systematic reviews. The majority of records (1985 RCTs and 260 systematic reviews) are in English. Manual therapy research is responsible for a large number of records on PEDro. There are just over 900 records coded as relevant to musculoskeletal physiotherapy and 425 where the method of treatment is coded as stretching, mobilisation, manipulation, massage. Of the 900 musculoskeletal records, 311 investigate treatment of the lumbar spine, sacro-iliac joint or pelvis, 150 investigate treatment of head and neck, 80 investigate treatment of the lower leg or knee, and 60 investigate treatment of the upper arm or shoulder. The earliest record on PEDro is a manipulation clinical trial: Coyer and Curwen’s 1955 clinical trial ‘Low back pain treated by manipulation’. Understandably, this trial did not have particularly high methodological quality (2/10). More contemporary musculoskeletal physiotherapy research is of much better quality. For example, the mean quality of the musculoskeletal physiotherapy trials published in 2000 is 7/10. As with any area of physiotherapy practice the clinical trials on PEDro in the area of musculoskeletal physiotherapy are of variable quality. Users of PEDro may be surprised, however, at how variable the quality is. The lowest score is 1/10 Manual Therapy (2000) 5(4), 223–226
226 Manual Therapy
and the highest is 9/10. This characteristic highlights one of the benefits of PEDro. In the past physiotherapists could order a paper through their library only to subsequently discover on reading the paper that the study was seriously flawed and so was unlikely to provide useful information on how to treat a patient. With the PEDro database physiotherapists can use the PEDro score to quickly discriminate between trials and plan their reading accordingly. No other database of clinical trials currently offers this service. Ideally abstracts of all indexed trials and reviews would be displayed on PEDro, however at this stage we have gained permission from copyright holders to display the abstracts for about half the records. Gaining permission to reproduce abstracts has been difficult because the 2426 records have come from 519 different journals. To date we have obtained permission to reproduce abstracts from 166 different journals. However 10 journals (including, notably, Archives of Physical Medicine and Rehabilitation) have either refused or have requested a large fee for displaying abstracts. Because PEDro is funded totally by donations there is no potential to pay fees to reproduce abstracts, so these abstracts are not displayed. Whether a journal has granted permission to reproduce abstracts on PEDro may be an issue a physiotherapy researcher should consider prior to signing over copyright when submitting their work for publication in a journal.
HELPING PEDro The PEDro database is a powerful tool for quickly identifying randomised trials and systematic reviews in physiotherapy. It will continue to be maintained by the Centre for Evidence-Based Physiotherapy while resources permit. Users of PEDro can assist in this endeavour in a number of ways. Firstly, users who know of randomised trials or systematic reviews that are not indexed on the database can notify the Centre for Evidence-Based Physiotherapy using a
Manual Therapy (2000) 5(4), 223–226
web-based form accessible from the PEDro site. The most urgent need is for identification of trials and systematic reviews published in languages other than English. Authors of new trials and systematic reviews could forward copies to the Centre (a mailing address is given in this paper). The most significant contribution involves rating trials on the basis of their methodological quality. People interested in rating trials can contact the Centre. Training in evaluation is given. Again, there is a particularly urgent need for evaluators who are able to read languages other than English, as a large proportion of non-English language trials have not yet been rated.
References Chalmers TC, Celano P, Sacks HS, Smith H 1983 Bias in treatment assignment in controlled clinical trials. New England Journal of Medicine 309: 1358–1361 Colditz GA, Miller JN, Mosteller F 1989 How study design affects outcomes in comparisons of therapy–I: medical. Statistics in Medicine 8: 441–454 Miller JN, Colditz GA, Mosteller F 1989 How study design affects outcomes in comparisons of therapy–II: surgical. Statistics in Medicine 8: 455–466 Moher D, Pham B, Jones A, Cook D, Jadad A, Moher M, Tugwell P and Klassen T 1998 Does quality of reports of randomised trials affect estimates of intervention efficacy reported in metaanalyses? Lancet 352 (9128): 609–613 Moseley A, Sherrington C, Herbert R and Maher C 1999 Reliability of a scale for measuring the methodological quality of clinical trials. Proceedings of the Cochrane Colloquium, Rome October 1999 National Health & Medical Research Council 1999. A guide to the Development, Implementation and Evaluation of Clinical Practice Guidelines. Canberra: (NHMRC) Sackett DL, Straus S, Richardon WS, Rosenberg W, Haynes RB (2000): Evidence-Based Medicine. How to Practice and Teach EBM (2nd edition). Edinburgh, Churchill Livingstone Sacks H, Chalmers TC, Smith H 1982 Randomized versus historical controls for clinical trials. American Journal of Medicine 72: 233–240 Schulz KF, Chalmers I, Hayes RJ, Altman DG 1995 Empirical evidence of bias: dimensions of methodological quality associated with estimates of treatment effects in controlled trials. Journal of the American Medical Association 273: 408–412 Verhagen A, de Vet H, de Bie R, Kessels A, Boers M, Bouter L and Knipschild P 1998 The Delphi List: A criteria list for quality assessment of randomized clinical trials for conducting systematic reviews developed by Delphi consensus. Journal of Clinical Epidemiology 51: 1235–1241
# 2000 Harcourt Publishers Ltd
Professional issue
PEDro. A database of randomized trials and systematic reviews in physiotherapy C. Sherrington* ,{, R. D. Herbert* ,{, C. G. Maher* ,{, A. M. Moseley*,} *Centre for Evidence-Based Physiotherapy, School of Physiotherapy, P.O. Box 170, Lidcombe NSW 1825, Australia. {Physiotherapy Department, Bankstown-Lidcombe Hospital, Sydney, Australia. {School of Physiotherapy, University of Sydney, Australia. }Rehabilitation Studies Unit, University of Sydney, Australia.
SUMMARY. This paper describes PEDro, the Physiotherapy Evidence Database. PEDro is a web-based database of randomized controlled trials and systematic reviews in physiotherapy. It can be accessed free of charge at http://ptwww.cchs.usyd.edu.au/pedro. The database contains bibliographic details and abstacts of most Englishlanguage randomized trials and systematic reviews in physiotherapy, and of many trials and reviews in other languages. Trials on the database are rated on the basis of their methodological quality so that users of the database can quickly identify trials of high quality. Trials and systematic reviews are extensively indexed to facilitate searching. PEDro provides an important information resource to support evidence-based clinical practice. # 2000 Harcourt Publishers Ltd.
relevant to manual therapy, and how to become involved in the PEDro initiative.
INTRODUCTION The Physiotherapy Evidence Database (PEDro) is a new database of randomised trials and systematic reviews in physiotherapy. The database, developed and maintained by the Centre for Evidence-Based Physiotherapy in Sydney, is freely available on the web. The URL is http://ptwww.cchs.usyd.edu.au/ pedro. PEDro was developed to give physiotherapists and consumers of physiotherapy services rapid access to the best available evidence of the effects of physiotherapy interventions. The best evidence of the effects of therapeutic interventions is usually considered to be provided by randomised controlled trials or by systematic reviews of randomised trials (National Health and Medical Research Council 1999). PEDro archives bibliographic details and abstracts of peer-reviewed published full reports of randomised controlled trials and systematic reviews in physiotherapy. Trials on the database are rated on the basis of their methodological quality so users can rapidly identify studies which are likely to be of the highest quality. This paper briefly describes the criteria and methods used to assemble PEDro, how PEDro can be used to find randomised trials and systematic reviews, a brief overview of the contents of PEDro
CRITERIA AND METHODS USED TO ASSEMBLE PEDro Locating trials Several methods have been used to locate the trials and systematic reviews that have been indexed on the PEDro database. The Rehabilitation and Related Therapies Field of the Cochrane Collaboration generously donated their pre-existing database of randomised trials in rehabilitation, which was combined with personal databases of the Steering Committee of the Centre for Evidence-Based Physiotherapy. This has been supplemented by optimised searches of three databases of the medical and allied health serials literature (Medline, Embase and Cinahl), a process which has now been automated. In addition, the Cochrane Database of Systematic Reviews and the Cochrane Clinical Trials Register were also searched. Each new release of these databases is also searched. Reference lists in systematic reviews on the PEDro database are checked for additional relevant publications. A large number of experts in various aspects of physiotherapy have also been contacted and many have assisted in the identification of relevant trials and reviews. Lastly,
Correspondence to: RH; E-mail: [email protected] 223
224 Manual Therapy
‘Friends of PEDro’ (volunteer physiotherapists who have assisted in the development and maintenance of the database) and users of PEDro regularly notify the Centre of trials that are not on PEDro, using a webbased notification form.
Inclusion criteria for trials Strict inclusion criteria are used to determine which studies will be indexed on PEDro. To be indexed, clinical trials must involve comparison of at least two interventions. One of these interventions could be a ‘no-treatment’ control or a ‘sham’ treatment. Alternately, the trial could involve comparisons of two interventions that are thought to be effective, with the aim of determining which is most effective. Crossover trials in which each subject is subjected to more than one intervention are included in PEDro provided the other criteria are also met. Interventions could include (but are not limited to) treatments, prevention strategies, diagnostic tests or techniques, or management or education strategies. At least one of the interventions must be currently part of physiotherapy practice or could become part of physiotherapy practice, however, the study need not be carried out by physiotherapists. Nor is it necessary that the interventions be carried out by a physiotherapist in the trial. The interventions must be applied to subjects who are representative, or who are intended to be representative, of those to whom the intervention might be applied in the course of physiotherapy practice. This usually means that the intervention is applied to people with a health condition or disability (in the case of a treatment) or at risk of developing a health condition or disability (in the case of a prevention strategy). Trials performed on animals rather than humans are not archived on PEDro. To be included in PEDro, the study must definitely have used random or intendedto-be-random allocation (intended-to-be random allocation refers to methods of allocation such as alternation or allocation by odd and even birth dates or hospital record numbers). If it is not certain that one of these methods of allocation was used the study is not included. Lastly, the paper must be a full paper, not an abstract published in a peer-reviewed journal.
Inclusion criteria for systematic reviews Systematic reviews are distinguished from traditional ‘narrative’ reviews by the use of methods to minimise bias. PEDro indexes those reviews of clinical trials in physiotherapy which contain a Methods section, and which review at least one trial which satisfies the other criteria listed above. Judgements of the quality of the methods used or whether the authors actually did what they claimed are not used to decide if a trial Manual Therapy (2000) 5(4), 223–226
or systematic review is eligible for inclusion in PEDro. Methods used to rate trial quality Each clinical trial on the PEDro database is rated on the basis of its methodological ‘quality’ using the PEDro scale. Systematic reviews are not rated. The 11-item PEDro scale is based on the 9-item Delphi list developed by Verhagen and colleagues at the Department of Epidemiology, University of Maastricht (Verhagen et al. 1998). Verhagen and colleagues used a formal method called the Delphi consensus technique to identify items that a panel of experts believed should be included in a scale of methodological quality. The purpose of the PEDro scale differs slightly from that of the Delphi list. The PEDro scale is designed to help the users of the PEDro database rapidly identify which of the randomised clinical trials indexed on the PEDro database are likely to be internally valid (items 2–9), and could have sufficient statistical information to make their results interpretable (items 10–11). One item (item 1) originally on the Delphi list has been retained on the PEDro scale so that the Delphi list is complete, but as this item relates to external validity this item is not used to calculate the PEDro score. The PEDro score is thus a score out of 10. Ideally those items on the PEDro scale designed to provide a measure of internal validity would be chosen on the basis of their demonstrated ability to predict bias. Several studies have begun to elucidate what features of study design best predict bias (e.g. Schulz et al. 1995). However, such studies are difficult to perform, not least because they need to be tested across a wide spectrum of clinical trials and they must assess very large numbers of studies to attain the necessary statistical precision; so information about predictive validity of scale items is still very incomplete. Many items on the Delphi list and the PEDro scale have been shown to predict bias in medical trials, e.g. randomization (Sacks et al. 1982; Chalmers et al. 1983; Colditz et al. 1989; Miller et al. 1989), concealment (Chalmers et al. 1983; Schulz et al. 1995; Moher et al. 1998) and blinding (Colditz et al. 1989; Schulz et al. 1995). But they are yet to be extensively validated on trials in physiotherapy. As more empirical data comes to hand it may become possible to delete those items on the PEDro scale which are not good predictors of bias, or ‘weight’ scale items so that the PEDro score reflects the importance of individual scale items. The Centre for EvidenceBased Physiotherapy is currently investigating the validity of the PEDro scale and PEDro scale items. The reliabilty of the PEDro scale has been tested (Moseley et al. 1999). The reliability of most items # 2000 Harcourt Publishers Ltd
PEDro 225
(agreement beyond chance) is moderate to high; Kappa ranged from 0.40 to 0.73, with a mean of 0.58. Total PEDro score has moderate reliability: ICC ¼ 0.54 (95% CI: 0.39–0.71). These reliability coefficients relate to judgements made by a single evaluator. To reduce error further, all trials are rated by two evaluators and when consensus is not reached they are arbitrated by a third evaluator. We caution users of PEDro that the PEDro scale should not be used as a measure of the ‘validity’ of a study’s conclusions. In particular, studies which show significant treatment effects and which score highly on the PEDro scale do not necessarily provide evidence that the treatment is clinically useful. Judgements of the clinical usefulness of a treatment must also involve consideration of whether the treatment effect was big enough to be clinically worthwhile, whether the positive effects of the treatment outweigh its negative effects, and the cost-effectiveness of the treatment. The scale should not be used to compare the ‘quality’ of trials performed across different areas of physiotherapy practice, primarily because it is not possible to satisfy all scale items in some areas of physiotherapy practice.
elbow) would be to search for trials classified as ‘stretching, mobilisation, manipulation, massage’ AND ‘elbow or forearm’. This returns 18 records, all randomised trials, of which approximately five are on manual therapy (depending on how strictly ‘manual therapy’ is defined). An alternate approach would be to type the terms ‘epicondylitis’ and ‘tennis’ in the abstract field, and combine them by clicking on ‘OR’ at the bottom of the search page. This returns 17 records, including the same 5 relevant trials. In general, searching for free words in the abstract is a more specific, and therefore more efficient, search strategy. Of the 5 relevant trials, PEDro scores ranged from 3/10 to 6/10 (two trials). Clicking on the titles returns bibliographic details and an abstract. The abstracts of the trials which scored 6/10 showed that progressive strengthening and stretching exercises were more effective at reducing pain and returning subjects to work than pulsed ultrasound, and that local cortico-steroid injections produced greater short-term reductions in symptoms than Cyriax-type manipulation. The clinician who was interested in the effects of manual therapy techniques on epicondylalgia would probably want to obtain full copies of these papers for a careful critical appraisal (see Sackett et al. 2000 for details).
FINDING TRIALS AND REVIEWS ON PEDro The PEDro database has been constructed in a way that makes it easy to search. All records on the database have been classified according to the therapy applied (e.g. ‘stretching, mobilisation, manipulation, massage’), the subdiscipline of physiotherapy (e.g. ‘musculoskeletal’), the problem being treated (e.g. ‘pain’), and the body part being treated (e.g. ‘head or neck’). Users can search for trials or systematic reviews by specifying particular classifications on any of these dimensions. Usually, however, the most efficient way to search the database is to search for free words in the abstract. If a number of search criteria are applied simultaneously they can be combined with logical/(AND or OR) operators (e.g. ‘neck AND pain’ or ‘neck OR cervical’). By default, PEDro searches for records which include search terms or any extensions of them. Thus, if the search term is ‘cervic’, PEDro will search for ‘cervical’ and ‘cervicogenic’ and any other word starting with cervic. When there are several variations of a search term (e.g. zygapophyseal, facet, facets), each variation can be included and combined with the OR operator. PEDro can be asked to search for series of words by including the series in inverted commas. Some of these principles will be illustrated by an example. One simple way to identify systematic reviews and clinical trials of the effects of manual therapy techniques for lateral epicondylitis (tennis # 2000 Harcourt Publishers Ltd
CONTENTS OF PEDro As at 28 July 2000 PEDro contained 2426 records of which 2160 were RCTs and 266 were systematic reviews. The majority of records (1985 RCTs and 260 systematic reviews) are in English. Manual therapy research is responsible for a large number of records on PEDro. There are just over 900 records coded as relevant to musculoskeletal physiotherapy and 425 where the method of treatment is coded as stretching, mobilisation, manipulation, massage. Of the 900 musculoskeletal records, 311 investigate treatment of the lumbar spine, sacro-iliac joint or pelvis, 150 investigate treatment of head and neck, 80 investigate treatment of the lower leg or knee, and 60 investigate treatment of the upper arm or shoulder. The earliest record on PEDro is a manipulation clinical trial: Coyer and Curwen’s 1955 clinical trial ‘Low back pain treated by manipulation’. Understandably, this trial did not have particularly high methodological quality (2/10). More contemporary musculoskeletal physiotherapy research is of much better quality. For example, the mean quality of the musculoskeletal physiotherapy trials published in 2000 is 7/10. As with any area of physiotherapy practice the clinical trials on PEDro in the area of musculoskeletal physiotherapy are of variable quality. Users of PEDro may be surprised, however, at how variable the quality is. The lowest score is 1/10 Manual Therapy (2000) 5(4), 223–226
226 Manual Therapy
and the highest is 9/10. This characteristic highlights one of the benefits of PEDro. In the past physiotherapists could order a paper through their library only to subsequently discover on reading the paper that the study was seriously flawed and so was unlikely to provide useful information on how to treat a patient. With the PEDro database physiotherapists can use the PEDro score to quickly discriminate between trials and plan their reading accordingly. No other database of clinical trials currently offers this service. Ideally abstracts of all indexed trials and reviews would be displayed on PEDro, however at this stage we have gained permission from copyright holders to display the abstracts for about half the records. Gaining permission to reproduce abstracts has been difficult because the 2426 records have come from 519 different journals. To date we have obtained permission to reproduce abstracts from 166 different journals. However 10 journals (including, notably, Archives of Physical Medicine and Rehabilitation) have either refused or have requested a large fee for displaying abstracts. Because PEDro is funded totally by donations there is no potential to pay fees to reproduce abstracts, so these abstracts are not displayed. Whether a journal has granted permission to reproduce abstracts on PEDro may be an issue a physiotherapy researcher should consider prior to signing over copyright when submitting their work for publication in a journal.
HELPING PEDro The PEDro database is a powerful tool for quickly identifying randomised trials and systematic reviews in physiotherapy. It will continue to be maintained by the Centre for Evidence-Based Physiotherapy while resources permit. Users of PEDro can assist in this endeavour in a number of ways. Firstly, users who know of randomised trials or systematic reviews that are not indexed on the database can notify the Centre for Evidence-Based Physiotherapy using a
Manual Therapy (2000) 5(4), 223–226
web-based form accessible from the PEDro site. The most urgent need is for identification of trials and systematic reviews published in languages other than English. Authors of new trials and systematic reviews could forward copies to the Centre (a mailing address is given in this paper). The most significant contribution involves rating trials on the basis of their methodological quality. People interested in rating trials can contact the Centre. Training in evaluation is given. Again, there is a particularly urgent need for evaluators who are able to read languages other than English, as a large proportion of non-English language trials have not yet been rated.
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