Inconsistent Medication Use Among US Adults With Diabetes

Relatively high percentages of patients with diabetes in the United States stopped or inconsistently used their medications meant to lower glucose, blood pressure, or lipid levels over time, according to a study published in JAMA Network Open.

The study looked at trends in use of these medications by adults with diabetes who participated in the Medical Expenditure Panel Survey (MEPS). Data from the MEPS allowed for serial cross-sections and 2-year longitudinal follow-up between 2 panels: one between 2005 and 2006, and another between 2018 and 2019. Data were analyzed between August 2021 and November 2022.

The study authors categorized longitudinal use of each medication type over the 2-year follow-up as continued use (defined as at least 1 prescription fill per year), no use, inconsistent use, and new use.

The study included 15,237 participants with diabetes, with most aged between 45 and 64 years (47.4%) and female (54.2%). Additionally, 42.6% where non-Latino White, 25.3% were Latino, and 23.8% were Black.

The study showed that a mean of 19.5%, 17.1%, and 43.3% of participants did not maintain continuity in use of glucose-, blood pressure–, or lipid-lowering medications, respectively, during both years of follow-up.

Trends in medication continuity also changed between the 2 panel years.

The percentage of participants who continued using glucose-lowering medication in both years trended down from 84.5% (95% CI, 81.8%-87.3%) between 2005 and 2006 to 77.4% (95% CI, 74.8%-80.1%) between 2018 and 2019.

This decrease coincided with increased rates of inconsistent use from 3.3% (95% CI, 1.9%-4.7%) in the first year to 7.1% (95% CI, 5.6%-8.6%) in the second year, as well as no use, which increased from 8.1% (95% CI, 6.0%-10.1%) in the first year to 12.9% (95% CI, 10.9%- 14.9%) in the second year.

Additionally, inconsistent use of blood pressure–lowering medication trended upward from 3.9% (95% CI, 1.8%-6.0%) in the first year to 9.0% (95% CI, 7.0%-11.0%) in the second year, while inconsistent use of lipid-lowering medication peaked at 9.9% (95% CI, 7.0%-12.7%) between 2017 and 2018.

The authors also noted that longitudinal use of glucose-lowering medications among US adults with diabetes has been explored using commercial payer and Medicare data.

“These data do not include individuals in uninsured or underinsured populations, who are more likely to experience barriers to or disruptions in access to care,” they said. “In our nationally representative data for adults with diabetes, uninsured adults were more likely to use no medications or inconsistently use medications for both years of follow-up, which is consistent with another study that found an association between financial barriers and medication adherence among adults with diabetes.”

They also found varying trends by race and age.

Patients with diabetes who were younger or Black were less likely to continue regular use of glucose-lowering medications, which the authors said is consistent with prior study findings. Additionally, Latino participants were more likely to inconsistently use blood pressure–lowering medications, while Black and Latino participants were less likely to maintain continuity in use of lipid-lowering medications.

Differences found between different racial and ethnic groups may reflect heterogenous individual and systemic factors, the authors said.

According to surveys, Latino participants with diabetes mentioned cost being a major barrier to medication adherence, while Black participants mentioned worsened complications and lack of trust in the US health care system and pharmaceutical therapies.

“The pharmaceutical industry, payers, clinicians and health systems, and policy makers have introduced interventions to improve medication adherence, such as use of clinician outreach and mail order pharmacies,” the authors said. “However, changes and inconsistencies in payer formularies and out-of-pocket cost burden, especially among adults with no or insufficient insurance (ie, Medicare Part D), remain prominent issues.”

According to the authors, these findings on longitudinal medication use by adults with diabetes may warrant multifaceted reforms to address inconsistent or no medication use.

Reference

Chehal PK, Uppal TS, Turbow S, et al. Continuity of medication use by US adults with diabetes, 2005-2019. JAMA Netw Open. 2023;6(1):e2253562. doi:10.1001/jamanetworkopen.2022.53562