Health insurance status, cost-related medication underuse, and outcomes among diabetes patients in three systems of care

Med Care. 2004 Feb;42(2):102-9. doi: 10.1097/01.mlr.0000108742.26446.17.


Background: Chronically ill patients often experience difficulty paying for their medications and, as a result, use less than prescribed.

Objectives: The objectives of this study were to determine the relationship between patients with diabetes' health insurance coverage and cost-related medication underuse, the association between cost-related underuse and health outcomes, and the role of comorbidity in this process.

Research design: We used a patient survey with linkage to insurance information and hemoglobin A1C (A1C) test results.

Patients: We studied 766 adults with diabetes recruited from 3 Veterans Affairs (VA), 1 county, and 1 university healthcare system.

Main outcomes: Main outcomes consisted of self-reported medication underuse as a result of cost, A1C levels, symptom burden, and Medical Outcomes Study 12-Item Short-Form physical and mental functioning scores.

Results: Fewer VA patients reported cost-related medication underuse (9%) than patients with private insurance (18%), Medicare (25%), Medicaid (31%), or no health insurance (40%; P <0.0001). Underuse was substantially more common among patients with multiple comorbid chronic illnesses, except those who used VA care. The risk of cost-related underuse for patients with 3+ comorbidities was 2.8 times as high among privately insured patients as VA patients (95% confidence interval, 1.2-6.5), and 4.3 to 8.3 times as high among patients with Medicare, Medicaid, or no insurance. Individuals reporting cost-related medication underuse had A1C levels that were substantially higher than other patients (P <0.0001), more symptoms, and poorer physical and mental functioning (all P <0.05).

Conclusions: Many patients with diabetes use less of their medication than prescribed because of the cost, and those reporting cost-related adherence problems have poorer health. Cost-related adherence problems are especially common among patients with diabetes with comorbid diseases, although the VA's drug coverage may protect patients from this increased risk.

Publication types

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

MeSH terms

  • Aged
  • Cost of Illness*
  • Diabetes Mellitus / drug therapy*
  • Diabetes Mellitus / economics*
  • Drug Utilization Review
  • Fees, Pharmaceutical / statistics & numerical data*
  • Female
  • Health Care Surveys
  • Hospitals, Veterans / economics
  • Hospitals, Veterans / statistics & numerical data*
  • Humans
  • Insurance Coverage / economics*
  • Insurance Coverage / statistics & numerical data
  • Insurance, Health / economics*
  • Insurance, Health / statistics & numerical data
  • Logistic Models
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Outcome Assessment, Health Care
  • Patient Compliance / statistics & numerical data
  • Socioeconomic Factors
  • United States
  • United States Department of Veterans Affairs