PURPOSE: To compare persistence and adherence among COPD patients treated with multiple- versus single- long-acting inhalers.
METHODS: Patients with ≥2 COPD medical claims (ICD-9-CM: 490.xx-492.xx, 494.xx-496.xx), ≥40 years old, ≥18 months continuous plan enrollment, and ≥2 prescriptions for a long-acting inhaler within 1 year were selected in the MarketScan database (2004−2008). Patients were classified as single-inhaler users (did not use concomitantly >1 long-acting inhaler) or multiple-inhaler users (filled ≥2 different LABA, LAMA, ICS, or ICS/LABA inhalers concomitantly). Single- and multiple-inhaler users were matched on age, gender, index year, comorbidities, COPD sub-type, prior COPD treatments, and prior number of exacerbations. Patients were followed for 12 months after the index date, defined as a randomly selected prescription date for single-inhaler users and a randomly selected date among concomitant prescription dates for multiple-inhaler users. Persistence, defined as time to treatment discontinuation (gap of >30 days), was compared between multiple- and single-inhaler users using Cox-proportional hazards models. Treatment adherence, measured by proportion of days covered (PDC) and dichotomized adherence (PDC≥0.8), was compared between the two groups. Logistic regressions were applied for dichotomized adherence. Sensitivity analyses were conducted using the same methods in poorly controlled patients (>1 exacerbation during the study period) and well controlled patients (no exacerbations during the study period).
RESULTS: 23,494 patients were grouped into 11,747 matched pairs. Among them, 9,235 (78.6%) single-inhaler users and 10,190 (86.7%) multiple-inhaler users discontinued their index treatment. After adjusting for confounding factors (age, gender, prior COPD treatments, and comorbidities), multiple-inhaler users had a significantly higher discontinuation rate (hazard ratio=1.40, p< 0.0001) compared to single-inhaler users. Furthermore, multiple-inhaler users were 34% less likely to be adherent (odds ratio=0.66, p< 0.0001) than single-inhaler users with an average PDC of 0.51 vs. 0.55 (p< 0.0001), respectively. Results were consistent for the poorly controlled and well-controlled groups.
CONCLUSION: Multiple-inhaler users were less adherent and had higher discontinuation rates compared to single-inhaler users.
CLINICAL IMPLICATIONS: Reduced inhaler burden may increase treatment adherence and improve treatment discontinuation for COPD patients.
DISCLOSURE: Andrew Yu, Grant monies (from industry related sources) Funding for this research was provided by Forest Laboratories, Inc. Analysis Group, Inc., has received research funds from Forest Laboratories, Inc.; Employee Andrew Peng Yu, Annie Guérin, Diego Ponce de Leon Barido, Karthik Ramakrishnan and Eric Wu are employees of Analysis Group, Inc. Juliana Setyawan, Michelle Dembiski and Steve Blum are employees of Forest Laboratories, Inc.; No Product/Research Disclosure Information