Q J Med 2002; 95: 23-26
© 2002 Association of Physicians
Costs of aspirin and statins in general practice
From the Department of Medicine, Manchester Royal Infirmary, Manchester, UK
Received 7 August 2001 and in revised form 28 September 2001
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Background: Aspirin and statins are the two drugs most commonly indicated for secondary prevention of atherosclerotic disease in the UK. Statin treatment, which is more expensive, is under-prescribed.
Aim: To assess the expenditure in Greater Manchester general practices on aspirin and statins.
Design: Survey of general practice records.
Methods: Practice registers were searched for patients receiving regular prescriptions for aspirin. For each patient, the next patient of the same sex, aged within ±5 years, not on aspirin, acted as a control. Details of all medications were recorded. In a sub-study, records of 100 patients on aspirin were studied to determine indications for aspirin prescription.
Results: There were 1003 (511 men, 492 women) in each group; mean age was 70 years in both groups. In the sub-study, 79% of patients received aspirin for established vascular disease, 9% for hypertension, 5% for diabetes mellitus, 5% for unknown reasons and 2% for arthritis. Of the patients on aspirin, 67% received dispersible aspirin 75 mg/day. The rest were on higher doses (10%) or on more expensive preparations (22%), costing up to 22.4 p/day. The mean daily cost of aspirin was 1.7p. Dyspepsia treatment was received by 266 patients and 194 controls (p<0.001). There was a wide range of dyspepsia medications (10–306p/day), averaging in the groups as a whole 15.5p/day in patients and 12.5p/day in controls. Of the patients on aspirin, 28% received statins, compared to 4% of controls. Mean daily expenditure on statins in patients was 23.4p.
Conclusion: Assuming the difference in the use of medication for dyspepsia between patients and controls was due to aspirin, the full cost of aspirin treatment was 4.7p/day. Statins were probably under-prescribed in aspirin-takers, many of whom would have been at high CHD risk.
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Introduction |
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Aspirin can reduce mortality and morbidity due to coronary heart disease (CHD) and cerebral thrombosis.1 Similar evidence also exists for statin therapy in patients with CHD, and the effects of aspirin and statins are additive.2 Aspirin is widely perceived as inexpensive3 and in surveys has been found to be the most consistently prescribed medication to patients with CHD, with almost 90% receiving it.4 There has not been a full health-economic evaluation of aspirin, but it is generally assumed that the cost of prescribing aspirin is 0.5p/day—the cost of dispersible aspirin 75 mg daily.5 The true cost in practice may however be higher, because although aspirin in higher doses may be no more effective,3 higher doses may nonetheless be prescribed. Furthermore, more expensive preparations may be used in practice, and concomitant medication for dyspepsia may be required for dyspeptic symptoms induced by the aspirin or to reduce the risk of peptic ulceration or gastric erosions. We therefore set out to estimate the actual cost of prescribing aspirin in general practice. We also examined expenditure on statin therapy, which is generally perceived to be expensive, in the aspirin-takers and controls.6
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Methods |
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Between May 2000 and December 2000, two of us (AD or JM) visited 10 general practices in Manchester (five in South Manchester, one in North Manchester, one in Central Manchester, one in Salford, one in Bury and one in Stockport). Details of the aspirin dose and preparation and concomitant medication received for a minimum of 3 months were recorded. Details of the first 100 patients (in alphabetical order) receiving repeat prescriptions for aspirin were taken from the practice computer at nine of the practices. The next patient on the practice register of the same sex aged within ±5 years was selected in each case as a control, and details of any medication he or she received were recorded. At the Central Manchester practice, 103 pairs of records rather than 100 were studied, due to a counting error. The inclusion of the three extra made no difference to the findings. For each patient and control, the cost of the particular dose and preparation of aspirin, any medication for dyspepsia, and statin treatment were recorded using the British National Formulary of March 2000, which was current at the time of the study.
To ensure that virtually all prescriptions for aspirin were for vascular disease, in a sub-study the records of 100 patients receiving aspirin were reviewed by one of us (SK) to determine the clinical indications for aspirin. In addition, the records of 600 patients in three practices were examined to determine the rate of prescribing of non-steroidal anti-inflammatory drugs. The study was conducted within the guidelines for medical audit and student projects of the Central Manchester Research Ethics Committee. In accordance with these, no data traceable to individual patients were recorded. Alphabetical sampling avoided the need to create a register of patient names. Differences between groups were tested using the 
2 test.
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Results |
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Of the 100 patients whose notes were studied in detail, 93% (95%CI 86–97%) were receiving aspirin as a means of preventing vascular disease: 14% (8–22%) for primary prevention, either diabetes or hypertension, and 79% (70–87%) for established CHD, past history of cerebral ischaemia or peripheral limb ischaemia. Only 2% (0–7%) received aspirin for arthritis and in 5% (2–11%) of records no reason for aspirin was recorded.
The mean cost of an aspirin prescription (Table 1
) was 1.7p daily. Although 67% (65–70%) of aspirin-takers were receiving dispersible aspirin 75 mg at a daily cost of 0.5p, the rest received larger doses and/or more expensive preparations. Of the latter, enteric coated aspirin, which cost 5.6p per 75 mg tablet, was the most frequent. The dose of aspirin exceeded 75 mg daily in 19% (17–22%) of aspirin-takers.
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Overall, 27% (24–30%) of those prescribed aspirin were also receiving anti-dyspeptic medication vs. 19% (17–22%) of controls, a difference which was statistically significant (p<0.001). This represented an average daily cost of 15.5p for each patient on aspirin and 12.5p for each control. Age had no discernible impact on either the proportion of aspirin-takers and controls receiving medication for dyspepsia or on its average cost. Thus 26.0% (22–30%) of patients on aspirin aged
70 years received dyspepsia treatment and 25% (21–29%) of those aged <70 did so. In controls, the figures were 21% (17–25%) for those aged 70 years and 16% (13–20%) for the younger group. The proportion of patients on aspirin also receiving non-steroidal anti-inflammatory drugs (5.7% (3.30–8.9%)) was similar to that in controls (5% (2.8–8.1%)). The greater use of medication for dyspepsia in the aspirin-takers was equivalent to an average daily expenditure of 3p for each patient, making the average cost of aspirin and the associated increment in expenditure on anti-dyspeptic medication 4.7p per day. The frequency with which indigestion remedies were prescribed in patients on enteric coated aspirin 75 mg daily was higher at 35% (28–44%) than in those on inexpensive, dispersible aspirin in a similar dose, in whom it was 23% (17–31%). A statin was prescribed to 28% (25–31%) of patients treated with aspirin and to 4% (3–5%) of those not on aspirin (difference p<0.001). The average daily expenditure on statins in the 1003 patients receiving aspirin was 23.4p. More statins were prescribed for younger patients: the likelihood of a patient aged <70 years receiving a statin was almost double that of an older patient (p<0.001)
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Discussion |
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The present study was not a cost-benefit-analysis and cannot answer questions about the overall cost of aspirin including, for example, hospitalization for cardiovascular disease, peptic ulceration and gastrointestinal haemorrhage balanced against its economic benefits in terms of reduced risk of cardiovascular and neoplastic disease. However, when such a study is undertaken, the true cost of aspirin prescription should be used. In practice this appears to be more than nine times the figure for dispersible aspirin 75 mg per day, often used to estimate the prescribing cost.5 It is nonetheless still relatively inexpensive. Statins, on the other hand, were prescribed to 28% of the aspirin-treated patients at a mean daily cost of 23.4p. However, the majority of the aspirin-treated patients had CHD, and most would be expected to have serum cholesterol levels exceeding 5 mmol/l.7 General practitioners were perhaps arbitrarily reluctant to prescribe statins for older patients. Even so, according to the National Service Framework8 the rate of statin prescribing in those aged <70 years should be at least double and, because many of the patients receiving statins were on the lowest doses, probably treble, if cholesterol targets were to be achieved.7
The aspirin-treated patients and controls were selected in alphabetical order, and this could conceivably have introduced some bias in our results, if the use of medication were different in people with names towards the end of the alphabet, but we consider this unlikely. Our conclusion could have been confounded if there was a greater likelihood of dyspepsia in patients with cardiovascular disease either because of a greater use in them of other medications provoking dyspepsia, such as non-steroidal anti-inflammatory drugs, or an association between cardiovascular disease and dyspepsia. We have excluded the possibility that there was greater use of non-steroidal anti-inflammatory drugs in patients receiving aspirin. We have been unable to find any evidence in the literature for an association between confirmed CHD and dyspepsia that included an adequately matched control group. The greatest likelihood for an association would clearly be if dyspepsia was itself misdiagnosed as angina. We did not collect data about the extent to which confirmatory investigations of the diagnosis of CHD were performed in our series of patients. However, although more limited investigation and thus the greatest possibility of misdiagnosis would probably have occurred in more elderly patients, there was no suggestion from our results that the use of more expensive aspirin preparations and antidyspeptic medications was greater in the elderly.
The largest increment in the cost of prescribing aspirin arose from the increased rate of prescription of anti-dyspepsia agents with protein pump inhibitors (PPIs), the most expensive of anti-dyspsia medications, representing 46.2% of such medication. The even higher rate of prescribing medication for dyspepsia associated with the prescription of enteric coated aspirin is probably because physicians tend to use enteric coated preparations in patients with dyspepsia, but there is no trial evidence to suggest that under such circumstances this is of any benefit.3,9 What is extraordinary is the high rate of prescribing of antidyspeptic drugs in the controls, most of whom were relatively healthy people. Again PPIs were the most prescribed medications, with 50.5% of prescriptions for dyspepsia being for these agents. It is questionable whether any health benefit could accrue from the daily expenditure of 12.5p in a typical group of 70-year-olds without vascular disease. It has been estimated that if the guidance of the National Institute for Clinical Excellence were fully implemented, it could lead to a reduction in the use of PPIs of at least 15%.10 Because patients without vascular disease in the general population greatly outnumber those with vascular disease even at the age of 70, the overall population expenditure on antidyspeptic medication of dubious benefit could, if diverted, contribute to the cost of expensive cardioprotective medication, such as statins, ACE inhibitors and beta-blockers, in the patients with vascular disease whose lives such treatment can extend.
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Acknowledgments |
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We are grateful to Ms C. Price for expertly preparing this manuscript. Support was received from the NHS Research and Development Levy. We thank the following general practitioners and their staff for allowing us access to their records: Dr Allen, Maples Medical Centre, Wythenshawe; Dr S. Child, Woodbank Surgery, Bury; Dr Chiu, Brunswick Health Centre, Chorlton-on-Medlock; Dr C. Crowther, Barlow Medical Centre, Didsbury; Dr Hennessy, The Avenue Medical Centre, Blackley; Dr K. Malone, The Daruzzaman Care Centre, Salford; Dr Norbury, Borchart Medical Centre, Withington; Dr G. Parker, The Archways Surgery, Stockport; Dr K. Shearer, Bowland Medical Practice, Wythenshawe; Dr H. Thompson, Brooklands Medical Practice, Brooklands.
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Notes |
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Address correspondence to Professor P.N. Durrington, Department of Medicine, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL. e-mail: pdurrington{at}central.cmht.nwest.nhs.uk
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References |
|---|
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TopSummaryIntroductionMethodsResultsDiscussionReferences |
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1. Antiplatelets Trialists Collaboration. Collaborative overview of randomised trials of antiplatelet therapy I. Prevention of death, myocardial infarction and stroke by prolonged antiplatelet therapy in various categories of patients. Br Med J1994; 308:81–106.
2.
Hebert PR, Gaziano JM, Chan KS, Hennekens CH. Cholesterol lowering with statin drugs, risk of stroke, and total mortality. An overview of randomised trials. JAMA1997; 278:313–21.
3.
Eccles M, Freemantle N, Mason J and the North of England Aspirin Guidelines Development Group. North of England evidence based guideline development project: guideline on the use of aspirin as secondary prophylaxis for vascular disease in primary care. Br Med J1998; 316:1303–9.
4.
Aspire Steering Group. A British Cardiac Society survey of the potential for the secondary prevention of coronary disease: ASPIRE (Action on Secondary Prevention through Intervention to Reduce Events). Principal results. Heart1996; 75:334–42.
5. Elwood PC. Aspirin: past, present and future. Clin Med JRCPL2001; 1:132–7.
6. Standing Medical Advisory Committee on use of statins. NHS Executive. London, Department of Health, May 1997.
7.
Primatesta P, Poulter NR. Lipid concentrations and the use of lipid lowering drugs: evidence from a national cross sectional survey. Br Med J2000; 321:1322–5.
8. Department of Health. National Service Framework for Coronary Heart Disease. London, The Stationery Office, 2000.
9.
Derry S, Loke YK. Risk of gastrointestinal haemorrhage with long term use of aspirin: meta-analysis. Br Med J2000; 321:1183–7.
10. National Institute for Clinical Excellence (NICE). Guidance on the use of proton pump inhibitors in the treatment of dyspepsia. NICE Technology Appraisal Guidance No 7, July 2000 (www.nice.org.uk).
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