Underutilization of Aspirin Persists in US Ambulatory Care for the Secondary and Primary Prevention of Cardiovascular Disease

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Measures

Our primary analytical goals were to assess the probability of aspirin use by CVD risk and its relationship to patient visit characteristics. The probability of aspirin use was defined as the proportion of non-contraindicated patient visits in which aspirin or a therapeutically equivalent medication was reported as a new or continuing medication. Measuring the probability of use by CVD risk provided a means to estimate the gaps between current practice and evidence-based medicine regarding aspirin therapy. We defined aspirin therapy as reported use of generic or brandname forms of aspirin, clopidogrel, ticlopidine, or non-narcotic combination analgesics containing aspirin. The number of patient visits in which clopidogrel or ticlopidine was reported is too small to allow their use over time being tracked separately. Oral anticoagulants are not considered aspirin equivalents and are not recommended for the primary or secondary prevention of CVD in the vast majority of patients. Moreover, judging the appropriateness of using or avoiding aspirin for someone who is already on anticoagulant therapy required more clinical detail than our data sources can provide. Therefore, we felt it was appropriate to exclude patients on anticoagulant therapy.We were unable to assess patientsÔÇÖ use of over-the-counter aspirin if it was not reported on the encounter form.We excluded visits by patients younger than 21 years and those with bleeding tendency, gastrointestinal bleeding, anticoagulant therapy, or clinically active hepatic disease.

Statistical Analyses

Statistical analyses accounting for sampling weights and the complex sample designs of NAMCS and NHAMCS were performed using SAS for Windows software (SAS Institute, Cary, North Carolina, US) and SAS-callable SUDAAN software (RTI, Research Triangle Park, North Carolina, US).The unit of analysis in both surveys was the patient visit. Comparisons of NAMCS and NHAMCS suggested limited differences on key outcome measures.We therefore combined the two surveys to obtain a wider range of outpatient settings and a broader socioeconomic spectrum of patients seeking ambulatory care. Also, to minimize random fluctuations between years,we analyzed data in two-year groupings, except for 2003, for depicting temporal trends in aspirin use. The SAS SURVEYMEANS procedure was performed, which generated national estimates of the probability of aspirin use by CVD risk and corresponding 99% confidence intervals (CIs).We chose to report 99% CIs in following National Center for Health Statistics analytical guidelines and also as a conservative measure to avoid over-interpretation of the findings.

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References
  1. Berg AO, Atkins D, Aspirin for the primary prevention of cardiovascular events. US Preventive Services Task Force , Ann Intern Med (2002); 136: pp. 157-160.
    Crossref | PubMed
  2. Pearson TA, Blair SN, Daniels SR, et al., AHA guidelines for primary prevention of cardiovascular disease and stroke: 2002 update. Consensus panel guide to comprehensive risk reduction for adult patients without coronary or other atherosclerotic vascular diseases.American Heart Association Science Advisory and Coordinating Committee , Circulation (2002); 106: pp. 388-391.
    Crossref | PubMed
  3. Hansson L, Zanchetti A, Carruthers S, et al., Effects of intensive blood-pressure lowering and low-dose aspirin in patients with hypertension: principal results of the Hypertension Optimal Treatment (HOT) randomized trial. HOT Study Group Lancet (1998); 351: pp. 1755-1762.
    Crossref | PubMed
  4. Steering Committee for the Physician's Health Study Research Group, Final report on the aspirin component of the ongoing Physician's Health Study , N Engl J Med (1989); 321: pp. 129-135.
    Crossref | PubMed
  5. Medical Research Council's General Practice Research Framework, Thrombosis prevention trial: Randomized trial of lowintensity oral anticoagulation with warfarin and low-dose aspirin in the primary prevention of ischaemic heart disease in men at increased risk , Lancet (1998); 351: pp. 233-241.
    Crossref | PubMed
  6. Collaborative Group of the Primary Prevention Project, Low-dose aspirin and vitamin E in people at cardiovascular risk:A randomized trial in general practice , Lancet (2001); 357: pp. 89-95.
    Crossref | PubMed
  7. Ridker PM, Cook NR, Lee IM, et al., A randomized trial of low-dose aspirin in the primary prevention of cardiovascular disease in women , N Engl J Med (2005); 352: pp. 1293-1304.
    Crossref | PubMed
  8. ISIS-2 Collaborative Group, Randomized trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. ISIS-2: Second International Study of Infarct Survival, Collaborative Group , Lancet (1988); 2: pp. 349-360.
    Crossref | PubMed
  9. Anti-Platelet Trialists' Collaboration, Collaborative meta-analysis of randomized trials of anti platelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients , Br Med J (2002); 324: pp. 71-86.
    Crossref | PubMed
  10. Weisman SM, Graham DY, Evaluation of the benefits and risks of low-dose aspirin in the secondary prevention of cardiovascular and cerebrovascular events , Arch Intern Med (2002); 162: pp. 2197-2202.
    Crossref | PubMed
  11. Chen Z, Sandercock P, Pan H, et al., Indications for early aspirin use in acute ischemic stroke.A combined analysis of 40,000 randomized patients from the Chinese Acute Stroke Trial and the International Stroke Trial , Stroke (2000); 31: pp. 1240-1249.
    Crossref | PubMed
  12. Harrington RA, Becker RC, Ezekowitz M, et al., Antithrombotic therapy for coronary artery disease:The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy , Chest (2004); 126: pp. 513S-548S.
    Crossref | PubMed
  13. Albers GW, Amarenco P, Easton JD, et al., Antithrombotic and thrombolytic therapy for ischemic stroke:The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy Chest (2004); 126: pp. 483S-512S.
    Crossref | PubMed
  14. American Diabetes Association, Aspirin therapy in diabetes , Diabetes Care (2004); 27: pp. S72-S73.
    Crossref | PubMed
  15. Stafford RS, Radley DC, The underutilization of cardiac medications of proven benefit, 1990 to 2002 , J Am Coll Cardiol (2003); 41: pp. 69-72.
  16. Stafford RS, Aspirin use is low among United States outpatients with coronary artery disease , Circulation (2000); 101: pp. 1097-1101.
    Crossref | PubMed
  17. Rolka DB, Fagot-Campagna A, Narayan KM, Aspirin use among adults with diabetes. Estimates from the Third National Health and Nutrition Examination Survey , Diabetes Care (2001); 24: pp. 197-201.
    Crossref | PubMed
  18. Kramer JM, Newby LK, Chang WC, et al., International variation in the use of evidence based medicines for acute coronary syndromes , Eur Heart J (2003); 24: pp. 2133-2141.
    Crossref | PubMed
  19. Venturini F, Romero M,Tognoni G, Patterns of practice for acute myocardial infarction in a population from ten countries , Eur J Clin Pharmacol (1999); 54: pp. 877-886.
    Crossref | PubMed
  20. O'Connor GT, Quinton HB,Traven ND, et al., Geographic variation in the treatment of acute myocardial infarction:The Cooperative Cardiovascular Project , JAMA (1999); 281: pp. 627-633.
    Crossref | PubMed
  21. Bennett KE, Williams D, Feely J, Under-prescribing of cardiovascular therapies for diabetes in primary care , Eur J Clin Pharmacol (2003); 58: pp. 835-841.
    Crossref | PubMed
  22. EUROASPIRE II Study Group, Lifestyle and risk factor management and use of drug therapies in coronary patients from 15 countries: Principal results from EUROASPIRE II Euro Heart Survey Programme , Eur Heart J (2001); 22: pp. 526-528.
  23. Steffenino G, Galliasso M, Gastaldi C, et al., Nurses' observational study on the practice of secondary prevention in a cardiovascular department , Ital Heart J (2003); 4: pp. 473-478.
    PubMed
  24. Avezum A, Makdisse M, Spencer F, et al., Impact of age on management and outcome of acute coronary syndrome: observations from the Global Registry of Acute Coronary Events (GRACE) , Am Heart J (2005); 149: pp. 67-73.
    Crossref | PubMed
  25. Meigs JB, Stafford RS, Cardiovascular disease prevention practices by U.S. physicians for patients with diabetes , J Gen Intern Med (2000); 15: pp. 220-228.
    Crossref | PubMed
  26. Califf RM, DeLong ER, Ostbye T, et al., Underuse of aspirin in a referral population with documented coronary artery disease , Am J Cardiol (2002); 89: pp. 653-661.
    Crossref | PubMed
  27. Ganz DA, Lamas GA, Orav EJ, et al., Age related differences in management of heart disease: A study of cardiac medication use in an older cohort. Pacemaker Selection in the Elderly (PASE) Investigators , J Am Geriat Soc (1999); 47: pp. 145-150.
    Crossref | PubMed
  28. Krumholz HM, Radford MJ, Ellerbeck EF, et al., Aspirin in the treatment of acute myocardial infarction in elderly Medicare beneficiaries. Patterns of use and outcomes , Circulation (1995); 92: pp. 2841-2847.
    Crossref | PubMed
  29. Zell ER, McCaig LF, Kupronis BA, et al., A comparison of the National Disease and Therapeutic Index and the National Ambulatory Medical Care Survey to evaluate antibiotic usage . In: Proceedings of the survey research methods section, Alexandria (Virginia):American Statistical Association (2000); pp 840-845.
  30. Gilchrist VJ, Stange KC, Flocke SA, et al., A comparison of the National Ambulatory Medical Care Survey (NAMCS) measurement approach with direct observation of outpatient visits , Medical Care (2004); 42: pp. 276-280.
    Crossref | PubMed
  31. Wilson PWF, D'Agostino RB, Levy D, et al., Prediction of coronary heart disease using risk factor categories , Circulation (1998); 97: pp. 1837-1847.
    Crossref | PubMed
  32. Colwell JA, Aspirin therapy in diabetes is underutilized , Diabetes Care (2001); 24: pp. 194-196.
    Crossref | PubMed
  33. Devereaux PJ,Anderson DR, Gardner MJ, et al. , Differences between perspectives of physicians and patients on anticoagulation in patients with atrial fibrillation: Observational study Br Med J (2001); 323: pp. 1218-1222.
  34. Laine L, The gastrointestinal effects of nonselective NSAIDs and COX-2-selective inhibitors , Semin Arthritis Rheum (2002); 32: pp. 25-32.
    Crossref | PubMed
  35. ETDRS Investigators, Aspirin effects on mortality and morbidity in patients with diabetes mellitus. Early Treatment Diabetic Retinopathy Study report 14 , JAMA (1992); 268: pp. 1292-1300.
    Crossref | PubMed
  36. Short D, Frischer M, Bashford J, Ashcroft D, Why are eligible patients not prescribed aspirin in primary care? A qualitative study indicating measures for improvement , BMC Fam Pract (2003); 4: p. 9.
  37. Martin CP,Talbert RL, Aspirin resistance: an evaluation of current evidence and measurement methods , Pharmacotherapy (2005); 25: pp. 942-953.
    Crossref | PubMed
  38. Lee PY, Chen WH, Ng W, et al., Low-dose aspirin increases resistance in patients with coronary artery disease , Am J Med (2005); 118: pp. 723-727.
    Crossref | PubMed
  39. Marshall T, Coronary heart disease prevention: Insights from modelling incremental cost effectiveness , Br Med J (2003); 327: pp. 1-5.
  40. Drummond A, Kwok S, Morgan J, Durrington PN, Costs of aspirin and statins in general practice , QJM (2001); 95: pp. 23-26.
    Crossref | PubMed
  41. Probstfield JF, How cost-effective are new preventive strategies for cardiovascular disease? , Am J Cardiol (2003); 91: pp. 22G-27G.
    Crossref | PubMed
  42. Hennekens CH, Sacks FM,Tonkin A, et al., Additive benefits of pravastatin and aspirin to decrease risks of cardiovascular disease , Arch Intern Med (2004); 164: pp. 40-44.
    Crossref | PubMed
  43. Ma J, Stafford RS, Cockburn IM, Finkelstein SN, A statistical analysis of the magnitude and composition of drug promotion in the United States in 1998 , Clin Ther (2003); 25: pp. 1503-1517.
    Crossref | PubMed
  44. Frances CD, Go AS, Dauterman KW, et al., Outcome following acute myocardial infarction: Are differences among physician specialties the result of quality of care or case mix? , Arch Intern Med (1999); 159: pp. 1429-1436.
    Crossref | PubMed
  45. Akosah KO, Larson DE, Brown WM, et al., Using a systemwide care path to enhance compliance with guidelines for acute myocardial infarction , Jt Comm J Qual Saf (2003); 29: pp. 245-259.
    PubMed