Adherence to antituberculous medication regimens in the United States: Insights from MarketScan databases, 2016-2022

Tuberculosis remains a major global public health problem. Adherence to antituberculous treatment is essential to prevent disease transmission and the emergence of multidrug-resistant tuberculosis. This study aims to evaluate adherence to first-line antituberculous medications in the United States.

A retrospective cohort study was conducted using data compiled in the Merative MarketScan commercial and Medicaid claims databases from 2016 to 2022. High adherence was defined as a proportion of days covered of ≥80% over a 6-month follow-up period. The study included patients with prescription claims for all 4 first-line antituberculous medications: isoniazid, rifampin, ethambutol, and pyrazinamide. Patients without continuous enrollment for 6 months prior to treatment initiation were excluded.

The final cohort included 168 Medicaid patients and 257 commercially insured patients. The lowest adherence was observed for isoniazid (Medicaid, 45.8% [95% CI, 38.1%-53.7%]; commercial plans, 50.2% [95% CI, 43.9%-56.5%]), followed by rifampin (56.6% [95% CI, 48.7%-64.2% in Medicaid). Higher adherence was observed for ethambutol (Medicaid, 71.4% [95% CI, 63.9%-78.1%]; commercial, 68.9% [95% CI, 62.8%-74.5%]) and pyrazinamide (Medicaid, 67.3% [95% CI, 59.6%-74.3%]; commercial, 71.6% (95% CI, 65.7%-77.0%]).

Adherence to first-line antituberculous medications remains suboptimal. Higher rates of adherence to ethambutol and pyrazinamide may reflect better adherence during the intensive treatment phase compared to the continuation phase.