Adherence of Elderly Patients with Cardiovascular Disease to Statins and the Risk of Exacerbation of Chronic Obstructive Pulmonary Disease: Evidence from an Italian Real-World Investigation

Abstract

Objective: The objective of this study was to investigate the relationship between adherence to statin therapy and the risk of exacerbation among elderly individuals affected by chronic obstructive pulmonary disease and cardiovascular disease.

Methods: Using the healthcare utilisation databases of five Italian territorial units accounting for nearly 35% of the Italian population, we recruited a cohort of 6263 elderly persons (i.e. aged 65 years or older) with co-existing chronic obstructive pulmonary disease and cardiovascular disease who initiated statin therapy. Exposure was adherence to statins measured by the proportion of days of follow-up covered. Outcome was the first hospital admission for chronic obstructive pulmonary disease occurring in the period of observation. A proportional hazards model was used to estimate the hazard ratio and 95% confidence intervals for the exposure-outcome association, after adjusting for several covariates. A set of sensitivity analyses was performed to account for sources of systematic uncertainty.

Results: During an average follow-up of about 4 years, 1307 cohort members experienced the outcome. Compared with patients with low adherence (proportion of days of follow-up covered ≤ 40%), those with intermediate (proportion of days of follow-up covered 41-80%) and high (proportion of days of follow-up covered > 80%) adherence exhibited a lower risk of exacerbation of 16% (95% confidence interval 3-27) and 23% (95% confidence interval 10-34).

Conclusions: In a real-world setting, we observed evidence that adherence to statin therapy markedly reduced the risk of chronic obstructive pulmonary disease exacerbations in elderly patients with co-existing chronic obstructive pulmonary disease and cardiovascular disease. Given the limited and controversial evidence from trials, more randomised controlled trials are urgently needed to better examine the potential benefits of statins as adjunct therapy in chronic obstructive pulmonary disease.