Cost-Related Medication Nonadherence in Adults With Diabetes in the United States: The National Health Interview Survey 2013–2018

Objective: Health-related expenditures due to diabetes are rising in the US. Medication nonadherence is associated with worse health outcomes among adults with diabetes. We sought to examine the extent of reported cost-related medication nonadherence (CRN) in individuals with diabetes in the US.

Research Design and Methods: We studied adults ≥18 with self-reported diabetes from the National Health Interview Survey (NHIS; 2013-18), a US nationally representative survey. Adults reporting skipping doses, taking less medication, or delaying filling a prescription to save money in the past year were considered to have experienced CRN. The weighted prevalence of CRN was estimated overall and by age subgroups (<65 and ≥65 years). Logistic regression was used to identify sociodemographic characteristics independently associated with CRN.

Results: Of the 20,326 NHIS participants with diabetes, 17.6% (weighted: 2.3 million) of those aged <65 reported CRN, compared with 6.9% (weighted: 0.7 million) among those aged ≥65. Financial hardship from medical bills, lack of insurance, low-income, high comorbidity burden and female sex were independently associated with CRN across age groups. Lack of insurance, duration of diabetes, current smoking, hypertension, and hypercholesterolemia were associated with higher odds of reporting CRN among the non-elderly, but not among the elderly. Among elderly, insulin use significantly increased the odds of reporting CRN (OR 1.51, 95% CI 1.18, 1.92).

Conclusions: In the US, 1 in 6 non-elderly and 1 in 14 elderly adults with diabetes reported CRN. Removing financial barriers to accessing medications may improve medication adherence among these patients, with the potential to improve their outcomes.