Income-related differences in the use of evidence-based therapies in older persons with diabetes mellitus in for-profit managed care

J Am Geriatr Soc. 2003 May;51(5):665-70. doi: 10.1034/j.1600-0579.2003.00211.x.


Objectives: To determine whether income influences evidence-based medication use by older persons with diabetes mellitus in managed care who have the same prescription drug benefit.

Design: Observational cohort design with telephone interviews and clinical examinations.

Setting: Managed care provider groups that contract with one large network-model health plan in Los Angeles County.

Participants: A random sample of community-dwelling Medicare beneficiaries with diabetes mellitus aged 65 and older covered by the same pharmacy benefit.

Measurements: Patients reported their sociodemographic and clinical characteristics. Annual household income (> or =$20,000 or <$20,000) was the primary predictor. The outcome variable was use of evidence-based therapies determined by a review of all current medications brought to the clinical examination. The medications studied included use of any cholesterol-lowering medications, use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) for cholesterol lowering, aspirin for primary and secondary prevention of cardiovascular disease, and angiotensin-converting enzyme (ACE) inhibitors in those with diabetic nephropathy. The influence of income on evidence-based medication use was adjusted for other patient characteristics.

Results: The cohort consisted of 301 persons with diabetes mellitus, of whom 53% had annual household income under $20,000. In unadjusted analyses, there were lower rates of use of all evidence-based therapies and lower rates of statin use for persons with annual income under $20,000 than for higher-income persons. In multivariate models, statin use was observed in 57% of higher-income versus 30% of lower-income respondents with a history of hyperlipidemia (P =.01) and 66% of higher-income versus 29% of lower-income respondents with a history of myocardial infarction (P =.03). There were no differences by income in the rates of aspirin or ACE inhibitor use.

Conclusion: Among these Medicare managed care beneficiaries with diabetes mellitus, all of whom had the same pharmacy benefit, there were low rates of use of evidence-based therapies overall and substantially lower use of statins by poorer persons.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Angiotensin-Converting Enzyme Inhibitors / therapeutic use
  • Aspirin / therapeutic use
  • Cohort Studies
  • Data Collection / methods
  • Diabetes Mellitus / drug therapy*
  • Diabetes Mellitus / economics
  • Evidence-Based Medicine*
  • Female
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / therapeutic use
  • Income*
  • Logistic Models
  • Male
  • Managed Care Programs / economics*
  • Medicare / economics
  • Quality of Health Care


  • Angiotensin-Converting Enzyme Inhibitors
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Aspirin