Statin exposure is associated with decreased asthma-related emergency department visits and oral corticosteroid use

Abstract

Rationale: Statins, or HMG-CoA reductase inhibitors, may aid in the treatment of asthma through their pleiotropic antiinflammatory effects.

Objectives: To examine the effect of statin therapy on asthma-related exacerbations using a large population-based cohort.

Methods: Statin users aged 31 years or greater with asthma were identified from the Population-Based Effectiveness in Asthma and Lung population, which includes data from five health plans. Statin exposure and asthma exacerbations were assessed over a 24-month observation period. Statin users with a statin medication possession ratio greater than or equal to 80% were matched to non-statin users by age, baseline asthma therapy, site of enrollment, season at baseline, and propensity score, which was calculated based on patient demographics and Deyo-Charlson conditions. Asthma exacerbations were defined as two or more oral corticosteroid dispensings, asthma-related emergency department visits, or asthma-related hospitalizations. The association between statin exposure and each of the three outcome measures was assessed using conditional logistic regression.

Measurements and main results: Of the 14,566 statin users, 8,349 statin users were matched to a nonuser. After adjusting for Deyo-Charlson conditions that remained unbalanced after matching, among statin users, statin exposure was associated with decreased odds of having asthma-related emergency department visits (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.53-0.77; P < 0.0001) and two or more oral corticosteroid dispensings (OR, 0.90; 95% CI, 0.81-0.99; P = 0.04). There were no differences in asthma-related hospitalizations (OR, 0.91; 95% CI, 0.66-1.24; P = 0.52).

Conclusions: Among statin users with asthma, statin exposure was associated with decreased odds of asthma-related emergency department visits and oral corticosteroid dispensings.

Figure 1.

(a) Flow for selection of statin users and nonusers from the Population-based Effectiveness in Asthma and Lung Diseases (PEAL) Asthma Cohort. (b) Timeline for assessment of baseline characteristics and asthma-related outcomes of statin users. Non–statin users were matched to statin users using propensity score and other covariates (see text). ICS = inhaled corticosteroids; LABA = long-acting β-agonist; LTI = leukotriene inhibitors; MPR = medication possession ratio; OCS = oral corticosteroids.

Figure 2.

Distribution of propensity scores for Kaiser Permanente Northern California before and after propensity score (PS) matching. Refer to Figure E1 for other enrollment sites.

Figure 3.

Love plot of the absolute standardized differences for demographics and baseline characteristics between statin users and non–statin users, before (open triangles) and after (closed circles) multivariate and propensity score matching. ED = emergency department; HPHC = Harvard Pilgrim Health Care; KPGA = Kaiser Permanente Georgia; KPNC = Kaiser Permanente Northern California.