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Reducing the risk after coronary artery bypass surgery
Public Health (1997) 111, 157–160 © The Society of Public Health, 1997
Reducing the risk after coronary artery bypass surgery: documentation of risk factors and communication between hospital and general practice J Wright and JR Strang Department of Public Health Medicine, North Yorkshire Health Authority, Sovereign House, Kettlestring Lane, Clifton Moor, York, YO3 4XF A retrospective descriptive study of patients who had had coronary artery bypass surgery was carried out to assess the completeness of recording of risk factors in case notes in hospital and in general practice, and to determine the prevalence of documented risk factors in patients who have had coronary artery bypass surgery. Data from reviews of hospital case notes and questionnaires to general practitioners were used to describe the frequency of documenting coronary risk factors and preventative advice in case notes and in correspondence between general practitioners and hospital doctors. Documentation of risk in hospital records revealed that all 102 patients had been assessed for family history, hypertension and current smoking, but 9 (9%) had no record of serum cholesterol, 35 (34%) patients did not have a record of their blood glucose, and in 83 (81%) patients there was no evidence that obesity had been assessed. Documentation of risk factors in general practice records identified that out of 77 patients, all had their blood pressure and smoking status recorded but 29 (38%) had not been assessed for hypercholesterolaemia. From the hospital records, the prevalence of risk factors in the sample population was 41% for hypertension or raised blood pressure, 49% for hypercholesterolaemia, 12% for current smoking and 8% for diabetes mellitus. In conclusion, patients who have had coronary artery bypass surgery have substantial needs for secondary prevention. A more structured approach to risk factor assessment and preventative care should begin as soon as the diagnosis of coronary heart disease is made, and should not be postponed until the patient has deteriorated to the point of needing bypass surgery. Keywords: coronary artery bypass surgery; risk factors; communication; general practice
Introduction Coronary artery bypass surgery is effective in relieving angina and has been demonstrated to prolong life in patients with coronary artery disease.1 In 1992–1993, 14 743 procedures were carried out in England,2 a 14% increase on the number of bypass grafts done in 1991– 1992. However, it is a palliative procedure, not a cure, in that the disease process may recur in the graft with adverse clinical consequences.3,4 It is important that this operation is not viewed as a ‘quick fix’ for coronary heart disease, but as one component of care to improve the patient’s quality of life, and to reduce the risk of future cardiac events.5 Smoking, hyperlipidaemia, hypertension, obesity, physical inactivity and diabetes are all relevant predictors of ischaemic heart disease. Risk factors which cannot be altered, such as age, sex, and a family history of coronary heart disease are still important to consider because of their synergistic effect on modifiable risk factors.6 Studies of patients who have undergone a second coronary artery bypass graft provide evidence that risk factors which are associated with atherosclerosis in coronary arteries also appear to contribute to atherosclerotic changes in bypass grafts.7,8 Furthermore, in patients who continue to smoke after surgery, survival at 10 y has been shown to be 84% among ex-smokers as compared to 68% among persistent smokers.9 With appropriate support it has been shown that it is possible to reduce the level of risk factors in patients Correspondence: Dr J Wright, Consultant in Epidemiology and Public Health, Bradford Royal Infirmary, Duckworth Lane, Bradford, BD9 6RJ, UK. Accepted 16 December 1996
undergoing coronary artery bypass surgery.10 For all patients with coronary heart disease including those who have been treated surgically, identifying risk factors and recording them in the medical records is a necessary prerequisite to meeting the patient’s need for preventative care. The aim of this study was to assess the completeness of recording risk factors in case notes in hospital and in general practice, and to determine the prevalence of documented risk factors in patients who have had coronary artery bypass surgery. A further aim was to measure the amount of information on risk factors and preventative advice included in correspondence between the general practitioner and the hospital doctor.
Methods All patients aged 35–74 y investigated at York District Hospital and who had undergone coronary artery bypass surgery at Castle Hill Hospital near Hull between February 1992 and April 1993 were included in the study. Patients were generally transferred from Castle Hill four to five days after surgery for post-operative care at York District Hospital prior to discharge home. Data were collected by one of us (JW) from an examination of the hospital records at York District Hospital which included the correspondence between the hospital doctor and the patient’s general practitioner. Data from general practice records were collected indirectly by means of a postal questionnaire sent to the patient’s family doctor requesting information on the documentation of risk factors for coronary artery disease.
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Data were collected on patient characteristics, recorded risk factors and advice documented on risk factor reduction. Patients were categorised as having hypertension, hypercholesterolaemia or diabetes on the basis of a prior diagnosis by the general practitioner or the hospital doctor. Results of the most recently documented blood pressure reading, serum cholesterol or blood glucose levels were also analysed. Hypercholesterolaemia was defined as a cholesterol level of > 6.5 mmol/l. An abnormal blood sugar was defined as a recording of > 6.0 mmol/l without subsequent investigation or comment. Diagnosing hypertension on a single blood pressure measurement is not valid, but particular note was made of patients with systolic blood pressures of 160 mm Hg or more, without subsequent recording or follow-up. A positive family history was defined as a first degree relative (parent or sibling) where coronary heart disease first occurred before the age of 60 y. An exercise history was defined as any documentation of the frequency or nature of exercise taken by the patient. An assessment of obesity was considered to be present if the body mass index or any comment on body weight was recorded in the case notes. To assess the communication between hospital and primary care, any information on risk factor prevalence or preventative advice in the referral letter from the general practitioner and in the letters from the hospital was recorded. All hospital letters were examined and considered as one group, and compared to the single referral letter from the family doctor.
Results During the study period 119 patients underwent coronary artery bypass grafting, of whom 102 (86%) had hospital records which were traced and examined. Four of these patients (4%) had undergone emergency procedures, the remainder (96%) had had elective surgery. The age of patients in the sample ranged from 41–74 y with a mean age of 60.7 y (s.d. 8.2 y). Seventy-nine (77%) patients were male. The mean interval between bypass surgery and the collection of data for the study was 12.5 months (range 5–18 months). Hospital records The completeness of assessing and documenting risk factors by hospital medical or nursing staff is shown in Table 1. All patients had been assessed for family history, hypertension and current smoking, but 9 (9%) patients had no record of serum cholesterol, 35 (34%) patients did not
have a record of their blood glucose, and in 83 (81%) patients there was no evidence that obesity had been assessed. A careful examination of the hospital records revealed that 9 (9%) patients had a last recorded systolic blood pressure of 160mm Hg or more yet did not have a provisional diagnosis of hypertension, 21 (21%) had a serum cholesterol greater than 6.4 mmol/l but had not been noted to have hypercholesterolaemia, and 3 (3%) patients had a last recorded blood glucose greater than 11 mmol/l, none of whom had been recorded as diabetic. None of the patients had a record of their body mass index in the hospital notes, the diagnosis of obesity in this study being based on comments about the patient being overweight. Consequently it was not possible to assess the proportion of the sample population who were not overweight or obese. The level of exercise taken by the sample population was poorly identified in the hospital records, and hence it was not possible to quantify risk in terms of physical inactivity. The ‘true’ documented prevalence of alterable risk factors in the sample population was obtained by adding those patients where the risk factor was present and documented together with those patients where the risk factor was found in the records but not identified as such by medical or nursing staff. This gives a ‘true’ prevalence of alterable risk factors in the sample population of 41% for hypertension or raised blood pressure, 49% for hypercholesterolaemia, 12% for current smoking, 8% for diabetes mellitus and 19% for being overweight. Only 19 (19%) had never smoked. A further 70 (69%) were ex-smokers. Four of the current smokers used a pipe only. Of the eight cigarette smokers, the mean number of cigarettes smoked daily was 13.8 (range 5–20). General practice records The documentation of risk factors in the general practice records of the sample population was analysed from the 77 (76%) questionnaires returned by family doctors. This part of the study focused on the recording of blood pressure, serum cholesterol and smoking only. All patients had their blood pressure recorded in the case notes, although 10 (13%) recordings were over one year old. Eighteen patients (23%) had a last recorded systolic blood pressure of over 160 mm Hg. Cholesterol measurements were present in 48 (62%) general practice records, of which 25 (52%) had a cholesterol level of 6.5 mmol/l or higher. Five of these patients had no record of hypercholesterolaemia in the hospital notes.
Table 1 Assessment and documentation of risk factors in hospital records. Figures are numbers (percentages) of hospital records. Risk factors
No record of assessment of risk factor
Risk factor documented as absent
Risk factor present and documented
Risk factor present but not documented
‘True’ risk factor prevalence
Total
Family history Hypertension/raised BP Hypercholesterolaemia Current smoking Diabetes Overweight
0 0 9 0 35 83
63 60 53 90 59 0
39 33 28 12 5 19
0 9 21 0 3 0
39 42 49 12 8 19
102 102 102 102 102 102
a
(0) (0) (9) (0) (34) (81)
(62) (59) (52) (88) (58)a (0)
(38) (32) (28) (12) (5) (19)
(0) (9) (21) (0) (3) (0)
33 out of 59 (56%) patients had a most recent blood glucose of greater than 6.0mmol/l but less than 11.0 mmol/l.
(38) (41) (49) (12) (8) (19)
(100) (100) (100) (100) (100) (100)
Coronary artery Surgery—risk reduction J Wright and JR Strang et al
Table 2 Number (percentage) of patients where letters from general practitioners (n 63) or hospital doctor (n 102) included information on risk factors Risk factor
Letter from GP
Letters from hospital
Blood pressure Smoking Cholesterol Weight Family history Exercise None mentioned
32 19 16 11 8 4 20
59 39 41 29 19 11 14
(51) (30) (25) (17) (13) (6) (32)
(58) (38) (40) (28) (19) (11) (14)
Nine (12%) patients were noted to be current smokers in the general practice records. However, four of these were not known to be current smokers from hospital records, and seven patients, recorded as current smokers in the hospital notes, were labelled as non-smokers in the practice records. The combined findings from both sets of medical records identified a total of 16 (16%) patients who had had a coronary artery bypass graft and who were noted to be current smokers. Correspondence The frequency of communicating information about risk factors in correspondence between hospital doctors and the referring general practitioners is shown in Table 2. All letters from hospital doctors relating to an individual patient were examined together as a group and compared to the single referral letter from the general practitioner which was present in 63 (62%) case records. Blood pressure was the commonest risk factor mentioned in correspondence from both general practitioners and from hospital doctors. Smoking status and the patient’s cholesterol level were documented in less than a third of the referral letters from general practitioners. There was a failure to make any mention of risk factors for coronary heart disease in 32% of referral letters from family doctors. Risk factors were documented more frequently in correspondence from hospital doctors to general practitioners, although in 14% of patients no mention was made of the presence of any risk factors. The referral letter from the general practitioner contained information about dietary advice given to the patient in only five (8%) cases with advice relating to exercise being included in only one (2%) letter. Referral letters were examined for five of the nine patients recorded as current smokers in the practice records. The type of support to help the patient give up smoking was described in only two cases. Letters from the hospital doctors contained dietary advice in 25 (25%) cases, advice about exercise in 24 (24%) cases, and smoking advice in 6 (50%) of the 12 patients recorded as current smokers by hospital staff.
Discussion Documenting risk There were important omissions in the documentation of risk factors in the hospital records particularly in relation to the measurement of obesity, serum cholesterol and blood glucose. Although all patients were routinely weighed and had their height recorded, the body mass index, which is
considered to be a worthwhile measure of body fatness,11 was not documented in any of the hospital records. Biochemical evidence of abnormally high cholesterol or glucose level was not always translated into a formal diagnosis of hypercholesterolaemia or diabetes mellitus respectively. Where a systolic blood pressure of 160 mm Hg or more was documented in patients not known to be hypertensive, the need for follow-up to exclude hypertension was not made explicit in the notes. Information on exercise was particularly deficient, perhaps due to the lack of any simple standardised recording method. The results from the self-completed postal questionnaire to general practitioners may have been subject to reporting bias and independent validation was beyond the scope of the study. In addition the questionnaire was deliberately brief in order to enhance the response rate. Distinction was not made between risk factor recording pre and postsurgery for these reasons and because the aim of the questionnaire was not to determine when risk factors had been documented but if they had been documented in primary care. While acknowledging these potential weaknesses, the results revealed that 38% of patients did not have a record of their cholesterol level in the practice records. There were important discrepancies regarding the occurrence of risk factors in the same patient comparing information from general practice with that in the hospital records. These differences partly reflect real changes in risk factors in patients being assessed at different times, but mainly relate to a failure to share important findings between the referring family doctor and the specialist in the elective referral letter and in the replies from the hospital for both elective and emergency cases. For those patients with documented risk factors, the type of support provided or considered appropriate to help the patient reduce their level of risk was rarely shared between the general practitioner and the hospital specialist. Documentation in hospital records of advice given to patients was generally poor, and although this does not necessarily reflect what advice the patients received, it would avoid unintended repetition and omission of advice if this information was clearly recorded.
Risk factor prevalence The prevalence of risk factors in this series, as recorded in the hospital case notes, demonstrates that there is a substantial need for secondary prevention in patients who have had coronary artery bypass surgery. The frequency of risk factors is comparable to that reported in other studies from America,12 and Australia.14 The latter study concluded that, except for smoking, the bypass patients had a worse profile of coronary risk factors than the general community.14 Forty percent of patients treated surgically in the Coronary Artery Surgery Study (CASS)12 had a cholesterol level of 6.5 mmol/l or more five years after surgery compared to 49% in this study. The same American study reported a smoking prevalence of 30% as compared to 16% in this series when data from hospital and general practice records were combined. The difference may largely effect the overall lower frequency of smoking in the 1990s compared to the pattern of smoking 15 y ago when data for CASS were collected. Nevertheless it is of concern that in this study one in six patients with angina severe enough to have warranted a bypass graft, continued to smoke after surgery.
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Conclusions Meeting the need for secondary prevention in patients being considered for a bypass graft requires that all risk factors are assessed and documented in an easily retrievable format. The responsibility for this assessment in elective cases lies initially with the primary care physician who should ensure that all relevant details are communicated to the hospital specialist at the time of referral. It is equally important for the hospital staff to relay new findings on risk factors back to the general practitioner. A more structured approach to communication between hospital doctors and general practitioners may help in this process.15,16 Consideration should also be given to the use of patient held cards to record up to date information on risk factors and details of preventative care particularly where this is provided by practice staff as well as through attendance at a hospital rehabilitation programme. Allowing the patient to have ownership of the information relating to their need for secondary prevention may contribute to reducing their level of risk for future cardiac events, provided that the approach responds sensitively to their readiness to change behaviour.17 This structured approach to preventative care should begin as soon as the diagnosis of coronary heart disease is made, and should not be postponed until the patient has deteriorated to the point of needing surgery. The Department of Health in The Health of the Nation18 has clearly identified that the surgical treatment of angina with coronary artery bypass grafting will contribute towards achieving the national mortality targets to be reached by the year 2000. The effectiveness of blanket health checks and primary prevention has been questioned by results of two recent studies.19,20 However the important role of health professionals in secondary and tertiary prevention is supported by evidence of clinical effectiveness.21 The cost effectiveness of providing appropriate preventative care is small in comparison with the combined cost of coronary angiography and bypass surgery, yet if risk factors are reduced, the patient may benefit appreciably in terms of length and quality of survival. It is for health authorities to ensure that they contract for appropriate preventative care as an integral component of a cardiology service. In turn, hospitals should demonstrate that care plans for all patients referred with coronary heart disease include recommendations for risk factor management and cardiac rehabilitation, and that relevant information is communicated both to the patient and to the referring doctor.
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14 15 16 17
Acknowledgement
18
We thank Dr Roger Boyle for his support and allowing access to his clinical records.
19
References 1 Yusof S et al. Effect of coronary artery bypass graft surgery on survival: overview of 10 year results from randomised trials by the coronary artery bypass graft surgery trialists collaboration. Lancet 1994; 344: 563–570. 2 Department of Health. Hospital Episode Statistics Volume 1: Finished consultant episodes by diagnosis, operation and
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speciality: England, financial year 1992–93. Prepared by the Government Statistical Service, November 1994. Smith SH, Geer JC. Morphology of saphenous vein—coronary artery bypass grafts: 7–116 months postoperatively. Arch Pathol Lab Med 1983; 107: 13–18. Badimon JJ, Ip J, Badimon L, Fuster V. Thrombosis and accelerated atherosclerosis in coronary bypass surgery and restenosis after percutaneous transluminal coronary angioplasty. Coronary Artery Disease 1990; 2: 170–179. Ramanathan KB et al. Interactive effects of age and other risk factors on long term survival after coronary artery surgery. J Am Coll Cardiol 1990; 15: 1493–1499. Grech ED, Ramsdale DR, Bray CL, Faragher EB. Family history as an independent risk factor of coronary heart disease. Eur Heart J 1992; 13: 1311–1315. Solymoss BC, Nadeau P, Millette D, Compean L. Late thrombosis of saphenous vein coronary artery bypass grafts related to risk factors. Circulation 1988; 78 (Suppl I): I-140– I-143. Neitzel GF, Barboriak JJ, Pintar K, Qureshi I. Atherosclerosis in aortocoronary bypass grafts. Morphologic study and risk factor analysis 6 to 12 years after surgery. Arteriosclerosis 1986; 6: 594–600. Cavender JB et al. Effects of smoking on survival and morbidity in patients randomized to medical or surgical therapy in the Coronary Artery Surgery Study (CASS): 10 year follow-up J Am Coll Cardiol 1992; 20 (2): 287–294. Engblom E et al. Coronary heart disease risk factors before and after bypass surgery: results of a controlled trial on multifactorial rehabilitation. Eur Heart J 1992; 13: 232–237. Committee on Medical Aspects of Food Policy. Nutritional Aspects of Cardiovascular Disease. Department of Health Report on Health and Social Subjects 46. HMSO: London, 1994. CASS Principal investigations and their associates: Coronary Artery Surgery Study (CASS): a randomised trial of coronary artery bypass surgery. Quality of life in patients randomly assigned to treatment groups. Circulation 1983; 68: 951–960. Hedback BEL, Perk J, Engvall J, Areskog NH. Cardiac rehabilitation after coronary artery bypass grafting: effects on exercise performance and risk factors. Arch Phys Med Rehabil 1990; 71: 1069–1073. Oldenburg B, Pierce J, Sicree R, Ross D. Coronary risk factor outcomes following coronary artery bypass surgery. Aust NZ J Med 1989; 19 (3): 234–240. Rawal J, Lloyd B, Barnett P. Use of structured letters to improve communication between hospital doctors and general practitioners. BMJ 1993; 307: 1044. Newton J, Eccles M, Hutchinson A. Communication between general practitioners and consultants: what should their letter contain? BMJ 1992; 304: 821–824. Stott NCH, Kinnersley P, Rollnick S. The limits to health promotion. BMJ 1994; 309: 971–972. Secretaries of State for Health, Wales, Scotland and Northern Ireland. The health of the nation: a strategy for health in England. HMSO: London, 1992. Imperial Cancer Research Fund OXCHECK Study Group. Effectiveness of health checks conducted by nurses in primary care: the results of the OXCHECK study after one year. BMJ 1994; 308: 308–312. Family Heart Study Group. Randomised controlled trial evaluating cardiovascular screening and intervention in general practice: principle results of the British Family Heart Study. BMJ 1994; 308: 313–320. Lau J et al. Cumulative meta-analysis of therapeutic trials for secondary prevention of myocardial infarction. N Eng J Med 1992; 327: 248–254.
Reducing the risk after coronary artery bypass surgery: documentation of risk factors and communication between hospital and general practice J Wright and JR Strang Department of Public Health Medicine, North Yorkshire Health Authority, Sovereign House, Kettlestring Lane, Clifton Moor, York, YO3 4XF A retrospective descriptive study of patients who had had coronary artery bypass surgery was carried out to assess the completeness of recording of risk factors in case notes in hospital and in general practice, and to determine the prevalence of documented risk factors in patients who have had coronary artery bypass surgery. Data from reviews of hospital case notes and questionnaires to general practitioners were used to describe the frequency of documenting coronary risk factors and preventative advice in case notes and in correspondence between general practitioners and hospital doctors. Documentation of risk in hospital records revealed that all 102 patients had been assessed for family history, hypertension and current smoking, but 9 (9%) had no record of serum cholesterol, 35 (34%) patients did not have a record of their blood glucose, and in 83 (81%) patients there was no evidence that obesity had been assessed. Documentation of risk factors in general practice records identified that out of 77 patients, all had their blood pressure and smoking status recorded but 29 (38%) had not been assessed for hypercholesterolaemia. From the hospital records, the prevalence of risk factors in the sample population was 41% for hypertension or raised blood pressure, 49% for hypercholesterolaemia, 12% for current smoking and 8% for diabetes mellitus. In conclusion, patients who have had coronary artery bypass surgery have substantial needs for secondary prevention. A more structured approach to risk factor assessment and preventative care should begin as soon as the diagnosis of coronary heart disease is made, and should not be postponed until the patient has deteriorated to the point of needing bypass surgery. Keywords: coronary artery bypass surgery; risk factors; communication; general practice
Introduction Coronary artery bypass surgery is effective in relieving angina and has been demonstrated to prolong life in patients with coronary artery disease.1 In 1992–1993, 14 743 procedures were carried out in England,2 a 14% increase on the number of bypass grafts done in 1991– 1992. However, it is a palliative procedure, not a cure, in that the disease process may recur in the graft with adverse clinical consequences.3,4 It is important that this operation is not viewed as a ‘quick fix’ for coronary heart disease, but as one component of care to improve the patient’s quality of life, and to reduce the risk of future cardiac events.5 Smoking, hyperlipidaemia, hypertension, obesity, physical inactivity and diabetes are all relevant predictors of ischaemic heart disease. Risk factors which cannot be altered, such as age, sex, and a family history of coronary heart disease are still important to consider because of their synergistic effect on modifiable risk factors.6 Studies of patients who have undergone a second coronary artery bypass graft provide evidence that risk factors which are associated with atherosclerosis in coronary arteries also appear to contribute to atherosclerotic changes in bypass grafts.7,8 Furthermore, in patients who continue to smoke after surgery, survival at 10 y has been shown to be 84% among ex-smokers as compared to 68% among persistent smokers.9 With appropriate support it has been shown that it is possible to reduce the level of risk factors in patients Correspondence: Dr J Wright, Consultant in Epidemiology and Public Health, Bradford Royal Infirmary, Duckworth Lane, Bradford, BD9 6RJ, UK. Accepted 16 December 1996
undergoing coronary artery bypass surgery.10 For all patients with coronary heart disease including those who have been treated surgically, identifying risk factors and recording them in the medical records is a necessary prerequisite to meeting the patient’s need for preventative care. The aim of this study was to assess the completeness of recording risk factors in case notes in hospital and in general practice, and to determine the prevalence of documented risk factors in patients who have had coronary artery bypass surgery. A further aim was to measure the amount of information on risk factors and preventative advice included in correspondence between the general practitioner and the hospital doctor.
Methods All patients aged 35–74 y investigated at York District Hospital and who had undergone coronary artery bypass surgery at Castle Hill Hospital near Hull between February 1992 and April 1993 were included in the study. Patients were generally transferred from Castle Hill four to five days after surgery for post-operative care at York District Hospital prior to discharge home. Data were collected by one of us (JW) from an examination of the hospital records at York District Hospital which included the correspondence between the hospital doctor and the patient’s general practitioner. Data from general practice records were collected indirectly by means of a postal questionnaire sent to the patient’s family doctor requesting information on the documentation of risk factors for coronary artery disease.
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Data were collected on patient characteristics, recorded risk factors and advice documented on risk factor reduction. Patients were categorised as having hypertension, hypercholesterolaemia or diabetes on the basis of a prior diagnosis by the general practitioner or the hospital doctor. Results of the most recently documented blood pressure reading, serum cholesterol or blood glucose levels were also analysed. Hypercholesterolaemia was defined as a cholesterol level of > 6.5 mmol/l. An abnormal blood sugar was defined as a recording of > 6.0 mmol/l without subsequent investigation or comment. Diagnosing hypertension on a single blood pressure measurement is not valid, but particular note was made of patients with systolic blood pressures of 160 mm Hg or more, without subsequent recording or follow-up. A positive family history was defined as a first degree relative (parent or sibling) where coronary heart disease first occurred before the age of 60 y. An exercise history was defined as any documentation of the frequency or nature of exercise taken by the patient. An assessment of obesity was considered to be present if the body mass index or any comment on body weight was recorded in the case notes. To assess the communication between hospital and primary care, any information on risk factor prevalence or preventative advice in the referral letter from the general practitioner and in the letters from the hospital was recorded. All hospital letters were examined and considered as one group, and compared to the single referral letter from the family doctor.
Results During the study period 119 patients underwent coronary artery bypass grafting, of whom 102 (86%) had hospital records which were traced and examined. Four of these patients (4%) had undergone emergency procedures, the remainder (96%) had had elective surgery. The age of patients in the sample ranged from 41–74 y with a mean age of 60.7 y (s.d. 8.2 y). Seventy-nine (77%) patients were male. The mean interval between bypass surgery and the collection of data for the study was 12.5 months (range 5–18 months). Hospital records The completeness of assessing and documenting risk factors by hospital medical or nursing staff is shown in Table 1. All patients had been assessed for family history, hypertension and current smoking, but 9 (9%) patients had no record of serum cholesterol, 35 (34%) patients did not
have a record of their blood glucose, and in 83 (81%) patients there was no evidence that obesity had been assessed. A careful examination of the hospital records revealed that 9 (9%) patients had a last recorded systolic blood pressure of 160mm Hg or more yet did not have a provisional diagnosis of hypertension, 21 (21%) had a serum cholesterol greater than 6.4 mmol/l but had not been noted to have hypercholesterolaemia, and 3 (3%) patients had a last recorded blood glucose greater than 11 mmol/l, none of whom had been recorded as diabetic. None of the patients had a record of their body mass index in the hospital notes, the diagnosis of obesity in this study being based on comments about the patient being overweight. Consequently it was not possible to assess the proportion of the sample population who were not overweight or obese. The level of exercise taken by the sample population was poorly identified in the hospital records, and hence it was not possible to quantify risk in terms of physical inactivity. The ‘true’ documented prevalence of alterable risk factors in the sample population was obtained by adding those patients where the risk factor was present and documented together with those patients where the risk factor was found in the records but not identified as such by medical or nursing staff. This gives a ‘true’ prevalence of alterable risk factors in the sample population of 41% for hypertension or raised blood pressure, 49% for hypercholesterolaemia, 12% for current smoking, 8% for diabetes mellitus and 19% for being overweight. Only 19 (19%) had never smoked. A further 70 (69%) were ex-smokers. Four of the current smokers used a pipe only. Of the eight cigarette smokers, the mean number of cigarettes smoked daily was 13.8 (range 5–20). General practice records The documentation of risk factors in the general practice records of the sample population was analysed from the 77 (76%) questionnaires returned by family doctors. This part of the study focused on the recording of blood pressure, serum cholesterol and smoking only. All patients had their blood pressure recorded in the case notes, although 10 (13%) recordings were over one year old. Eighteen patients (23%) had a last recorded systolic blood pressure of over 160 mm Hg. Cholesterol measurements were present in 48 (62%) general practice records, of which 25 (52%) had a cholesterol level of 6.5 mmol/l or higher. Five of these patients had no record of hypercholesterolaemia in the hospital notes.
Table 1 Assessment and documentation of risk factors in hospital records. Figures are numbers (percentages) of hospital records. Risk factors
No record of assessment of risk factor
Risk factor documented as absent
Risk factor present and documented
Risk factor present but not documented
‘True’ risk factor prevalence
Total
Family history Hypertension/raised BP Hypercholesterolaemia Current smoking Diabetes Overweight
0 0 9 0 35 83
63 60 53 90 59 0
39 33 28 12 5 19
0 9 21 0 3 0
39 42 49 12 8 19
102 102 102 102 102 102
a
(0) (0) (9) (0) (34) (81)
(62) (59) (52) (88) (58)a (0)
(38) (32) (28) (12) (5) (19)
(0) (9) (21) (0) (3) (0)
33 out of 59 (56%) patients had a most recent blood glucose of greater than 6.0mmol/l but less than 11.0 mmol/l.
(38) (41) (49) (12) (8) (19)
(100) (100) (100) (100) (100) (100)
Coronary artery Surgery—risk reduction J Wright and JR Strang et al
Table 2 Number (percentage) of patients where letters from general practitioners (n 63) or hospital doctor (n 102) included information on risk factors Risk factor
Letter from GP
Letters from hospital
Blood pressure Smoking Cholesterol Weight Family history Exercise None mentioned
32 19 16 11 8 4 20
59 39 41 29 19 11 14
(51) (30) (25) (17) (13) (6) (32)
(58) (38) (40) (28) (19) (11) (14)
Nine (12%) patients were noted to be current smokers in the general practice records. However, four of these were not known to be current smokers from hospital records, and seven patients, recorded as current smokers in the hospital notes, were labelled as non-smokers in the practice records. The combined findings from both sets of medical records identified a total of 16 (16%) patients who had had a coronary artery bypass graft and who were noted to be current smokers. Correspondence The frequency of communicating information about risk factors in correspondence between hospital doctors and the referring general practitioners is shown in Table 2. All letters from hospital doctors relating to an individual patient were examined together as a group and compared to the single referral letter from the general practitioner which was present in 63 (62%) case records. Blood pressure was the commonest risk factor mentioned in correspondence from both general practitioners and from hospital doctors. Smoking status and the patient’s cholesterol level were documented in less than a third of the referral letters from general practitioners. There was a failure to make any mention of risk factors for coronary heart disease in 32% of referral letters from family doctors. Risk factors were documented more frequently in correspondence from hospital doctors to general practitioners, although in 14% of patients no mention was made of the presence of any risk factors. The referral letter from the general practitioner contained information about dietary advice given to the patient in only five (8%) cases with advice relating to exercise being included in only one (2%) letter. Referral letters were examined for five of the nine patients recorded as current smokers in the practice records. The type of support to help the patient give up smoking was described in only two cases. Letters from the hospital doctors contained dietary advice in 25 (25%) cases, advice about exercise in 24 (24%) cases, and smoking advice in 6 (50%) of the 12 patients recorded as current smokers by hospital staff.
Discussion Documenting risk There were important omissions in the documentation of risk factors in the hospital records particularly in relation to the measurement of obesity, serum cholesterol and blood glucose. Although all patients were routinely weighed and had their height recorded, the body mass index, which is
considered to be a worthwhile measure of body fatness,11 was not documented in any of the hospital records. Biochemical evidence of abnormally high cholesterol or glucose level was not always translated into a formal diagnosis of hypercholesterolaemia or diabetes mellitus respectively. Where a systolic blood pressure of 160 mm Hg or more was documented in patients not known to be hypertensive, the need for follow-up to exclude hypertension was not made explicit in the notes. Information on exercise was particularly deficient, perhaps due to the lack of any simple standardised recording method. The results from the self-completed postal questionnaire to general practitioners may have been subject to reporting bias and independent validation was beyond the scope of the study. In addition the questionnaire was deliberately brief in order to enhance the response rate. Distinction was not made between risk factor recording pre and postsurgery for these reasons and because the aim of the questionnaire was not to determine when risk factors had been documented but if they had been documented in primary care. While acknowledging these potential weaknesses, the results revealed that 38% of patients did not have a record of their cholesterol level in the practice records. There were important discrepancies regarding the occurrence of risk factors in the same patient comparing information from general practice with that in the hospital records. These differences partly reflect real changes in risk factors in patients being assessed at different times, but mainly relate to a failure to share important findings between the referring family doctor and the specialist in the elective referral letter and in the replies from the hospital for both elective and emergency cases. For those patients with documented risk factors, the type of support provided or considered appropriate to help the patient reduce their level of risk was rarely shared between the general practitioner and the hospital specialist. Documentation in hospital records of advice given to patients was generally poor, and although this does not necessarily reflect what advice the patients received, it would avoid unintended repetition and omission of advice if this information was clearly recorded.
Risk factor prevalence The prevalence of risk factors in this series, as recorded in the hospital case notes, demonstrates that there is a substantial need for secondary prevention in patients who have had coronary artery bypass surgery. The frequency of risk factors is comparable to that reported in other studies from America,12 and Australia.14 The latter study concluded that, except for smoking, the bypass patients had a worse profile of coronary risk factors than the general community.14 Forty percent of patients treated surgically in the Coronary Artery Surgery Study (CASS)12 had a cholesterol level of 6.5 mmol/l or more five years after surgery compared to 49% in this study. The same American study reported a smoking prevalence of 30% as compared to 16% in this series when data from hospital and general practice records were combined. The difference may largely effect the overall lower frequency of smoking in the 1990s compared to the pattern of smoking 15 y ago when data for CASS were collected. Nevertheless it is of concern that in this study one in six patients with angina severe enough to have warranted a bypass graft, continued to smoke after surgery.
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Conclusions Meeting the need for secondary prevention in patients being considered for a bypass graft requires that all risk factors are assessed and documented in an easily retrievable format. The responsibility for this assessment in elective cases lies initially with the primary care physician who should ensure that all relevant details are communicated to the hospital specialist at the time of referral. It is equally important for the hospital staff to relay new findings on risk factors back to the general practitioner. A more structured approach to communication between hospital doctors and general practitioners may help in this process.15,16 Consideration should also be given to the use of patient held cards to record up to date information on risk factors and details of preventative care particularly where this is provided by practice staff as well as through attendance at a hospital rehabilitation programme. Allowing the patient to have ownership of the information relating to their need for secondary prevention may contribute to reducing their level of risk for future cardiac events, provided that the approach responds sensitively to their readiness to change behaviour.17 This structured approach to preventative care should begin as soon as the diagnosis of coronary heart disease is made, and should not be postponed until the patient has deteriorated to the point of needing surgery. The Department of Health in The Health of the Nation18 has clearly identified that the surgical treatment of angina with coronary artery bypass grafting will contribute towards achieving the national mortality targets to be reached by the year 2000. The effectiveness of blanket health checks and primary prevention has been questioned by results of two recent studies.19,20 However the important role of health professionals in secondary and tertiary prevention is supported by evidence of clinical effectiveness.21 The cost effectiveness of providing appropriate preventative care is small in comparison with the combined cost of coronary angiography and bypass surgery, yet if risk factors are reduced, the patient may benefit appreciably in terms of length and quality of survival. It is for health authorities to ensure that they contract for appropriate preventative care as an integral component of a cardiology service. In turn, hospitals should demonstrate that care plans for all patients referred with coronary heart disease include recommendations for risk factor management and cardiac rehabilitation, and that relevant information is communicated both to the patient and to the referring doctor.
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Acknowledgement
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We thank Dr Roger Boyle for his support and allowing access to his clinical records.
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References 1 Yusof S et al. Effect of coronary artery bypass graft surgery on survival: overview of 10 year results from randomised trials by the coronary artery bypass graft surgery trialists collaboration. Lancet 1994; 344: 563–570. 2 Department of Health. Hospital Episode Statistics Volume 1: Finished consultant episodes by diagnosis, operation and
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