BACKGROUND: Patients with COPD typically have multiple comorbidities and use multiple medications. Adherence rates for maintenance COPD medications maybe impacted by use of medications for other chronic conditions (non-COPD medications). It is important to assess the association between non-adherence to maintenance COPD medications and non-COPD medications.
OBJECTIVE: Evaluate the association between non-adherence to COPD medications and non-COPD medications in patients with COPD.
METHODS: A cohort of patients with evidence of COPD diagnosis was identified using Humana’s claims database. Selected patients were 40-89 years old and continuously enrolled for 12 months prior to and 24 months after the first identified COPD diagnosis (index date) during January 1, 2008-December 31, 2010. Patients were required to have ≥1 prescription fill for a COPD medication (Long-Acting Antimuscarinic Agents [LAMAs] or maintenance Fixed Dose Combinations [FDC] combinations) within 365 days of the index date and ≥1 prescription fill for a non-COPD medication (antihypertensives, statins, diuretics, beta-blockers, calcium channel blockers, anticoagulants, antidepressants, anxiolytics, nonsteroidal anti-inflammatory drugs [NSAIDs], antidiabetics, insulin, or bisphosphonates) within ±30 days of the first COPD prescription. Adherence (proportion of days covered [PDC]) was measured during 365 days following the first COPD prescription. The association between non-adherence (PDC< 0.8) to COPD and non-COPD medications was determined using logistic regression, controlling for baseline patient characteristics; odds ratio (OR) and 95% confidence interval (CI) were computed.
RESULTS: A total of 14,117 patients, with a mean age of 69.9 years, met study criteria. Of these, 40.9% were male and 79.2% were nonadherent to COPD medications. The mean PDC for COPD medications was 0.47. Antihypertensives, statins and diuretics were the most commonly prescribed non-COPD medications with a mean PDC of 0.71, 0.67 and 0.61, respectively. Non-adherence to COPD medications was associated with non-adherence to all non-COPD medications (OR 1.38 to 1.78, all P<0.01) except anticoagulants and anxiolytics. The strongest predictors of non-adherence to COPD medications were nonadherence to insulins (OR [95% CI]: 1.78 [1.28-2.47], NSAIDs 1.74 [1.39-2.18]) and antidepressants (1.73 [1.50-1.99]).
CONCLUSIONS: The majority of patients with COPD in this study were non-adherent to COPD medications. Non-adherence to COPD medications was associated with non-adherence to 10 of the 12 nonCOPD medications assessed.
