Poor adherence to chronic obstructive pulmonary disease medications in primary care: Role of age, disease burden and polypharmacy

Aim The aim of the present study was to assess the occurrence and determinants of poor adherence to pharmacological treatment in a cohort of primary care patients with chronic obstructive pulmonary disease (COPD), paying special attention to the role of age, comorbidity and polypharmacy. Methods We identified a cohort of COPD patients using the primary care Italian Health Search – IMS Longitudinal Patient Database. We assessed 1-year adherence to COPD maintenance pharmacotherapy (encompassing inhaled corticosteroids, long-acting beta agonists and long-acting anticholinergics). Poor adherence was defined as <80% of proportion of days covered by pharmacological treatment over a 1-year period. Results Of 22 505 patients (mean age 67.3 ± 13.2; 41.3% women) entering the study, 17 486 (77.7%) were poorly adherent. According to multivariate analysis, poor adherence is less likely in older adults (OR 0.51, 95% CI 0.40–0.66), in non-smokers (OR 0.77, 95% CI 0.69–0.86) and in those with a history of alcohol abuse (OR 0.74, 95% CI 0.58–0.94). Higher comorbidity (OR 1.43, 95% CI 1.13–1.80) was positively associated with poor adherence. Polypharmacy was associated with poor adherence only in patients aged ≥65 years (OR 1.34, 95% CI 1.13–1.59). Finally, COPD severity was associated with a reduced likelihood of poor adherence (OR 0.20, 95% CI 0.07–0.61 for stage IV). Conclusions The present findings show that poor medication adherence is common in patients with COPD receiving long-term treatment. The interaction between age and polypharmacy, and the role of comorbidity suggest a pivotal role of biological age as a steering determinant of poor adherence. Geriatr Gerontol Int 2017; 17: 2500–2506.