BACKGROUND For patients with atrial fibrillation (AF), early treatment is essential to prevent serious complications such as stroke. Several randomized clinical trials have shown that rate-control may be as effective as rhythm-control medications, whereas the latter have serious side effects. Little evidence exists, however, about which class of rate-control medication-β-blockers (BBs) or calcium channel blockers (CCBs)-may be superior. OBJECTIVE The objective was to compare the long-term persistence on BBs versus CCBs in nonelderly adult patients with AF. METHODS A longitudinal retrospective cohort study for patients 40 to 60 years old with newly diagnosed AF (identified by ICD-9 code 427.31) was performed using data from Ohio Medicaid physician, institutional, and pharmacy claims from January 2006 through June 2011. A Cox proportional hazard regression, with time to change out of rate-control therapy as the dependent variable, was estimated to compare persistence on (proxy for effectiveness of) rate-control medication across drug classes. A propensity-score analysis was used to control for selection bias. Additional covariates included age, development of heart failure, and medication adherence. RESULTS Out of 1239 patients included in the cohort, 1016 received a BB; 223 received a CCB. Over time, patients on CCBs were significantly more likely to switch out of rate-control therapy (hazard ratio = 1.89; 95% CI = 1.14-3.09) than patients on BBs. CONCLUSIONS Evidence suggests that nonelderly AF patients, when prescribed rate-control therapy, persist longer on BBs than CCBs. Because this is the first long-term study comparing the 2 drug classes in the nonelderly population, further research is suggested.