Real-world adherence and persistence associated with nebivolol or hydrochlorothiazide as add-on treatment for hypertension

Objective: To compare adherence and persistence associated with nebivolol and hydrochlorothiazide (HCTZ) as add-on hypertension treatments. Research design and methods: Adults with >= 1 hypertension diagnosis (ICD-9-CM 401-405) who used nebivolol or HCTZ as their first add-on antihypertensive therapy between 1/1/2008 and 9/30/2010 were identified from a large claims database. Patients had continuous enrollment for >= 1 year preceding (baseline period) and following (study period) the first qualifying prescription fill, and did not use nebivolol or HCTZ during the baseline period. A random sample of HCTZ patients meeting selection criteria were selected in a 3:1 ratio to nebivolol patients. Main outcome measures: The probability of receiving each drug, adjusted for baseline patient demographics, significantly different comorbidities, and costs was estimated using a logistic model. Inverse propensity score weights were used to balance confounding factors for between-cohort comparisons. Adherence (estimated using the medication possession ratio [MPR]) and persistence (estimated as days from initiation to the first >30 day gap in the index drug supply) at 6, 9, and 12 months were compared using weighted t tests. Results: Baseline characteristics of nebivolol (n = 722) and HCTZ (n = 2166) patients were well balanced after weighting. At 12 months, nebivolol patients had a significantly higher MPR than HCTZ patients (0.76 vs. 0.70, P < 0.001), and medication persistence was 28 days longer (273 vs. 245 days, P < 0.001). Between-group differences were also significant at 6 and 9 months. Conclusions: When used as an add-on therapy for hypertension, nebivolol was associated with significantly higher rates of adherence and persistence compared with HCTZ, after adjusting for baseline differences between treatment groups. These results may be impacted by limitations inherent in insurance claims data, such as the lack of clinical information.