Statin Use Is Associated with Reduced Mortality in Patients with Interstitial Lung Disease

Abstract

Introduction: We hypothesized that statin use begun before the diagnosis of interstitial lung disease is associated with reduced mortality.

Methods: We studied all patients diagnosed with interstitial lung disease in the entire Danish population from 1995 through 2009, comparing statin use versus no statin use in a nested 1:2 matched study.

Results: The cumulative survival as a function of follow-up time from the date of diagnosis of interstitial lung disease (n = 1,786 + 3,572) and idiopathic lung fibrosis (n = 261 + 522) was higher for statin users versus never users (log-rank: P = 7 · 10(-9) and P = 0.05). The median survival time in patients with interstitial lung disease was 3.3 years in statin users and 2.1 years in never users. Corresponding values in patients with idiopathic lung fibrosis were 3.4 versus 2.4 years. After multivariable adjustment, the hazard ratio for all-cause mortality for statin users versus never users was 0.73 (95% confidence interval, 0.68 to 0.79) in patients with interstitial lung disease and 0.76 (0.62 to 0.93) in patients with idiopathic lung fibrosis. Results were robust in all sensitivity analyses.

Conclusion: Among patients with interstitial lung disease statin use was associated with reduced all-cause mortality.

Fig 1. Inclusion of interstitial lung disease patients during 1995 through 2009.

Patients were divided into regular statin users and never users. A, Entire Danish population. B. Nested 1:2 matched study.

Fig 2. Selection of interstitial lung disease patients entering into the study.

Patients were divided into regular statin users and never users for the nested 1:2 matched study.

Fig 3. Survival and risk of all-cause mortality in statin users versus never users.

Patients with interstitial lung disease (A) and patients with idiopathic lung fibrosis (B). Hazard ratios are shown after multivariable adjustments.

Fig 4. Risk of all-cause and cause-specific mortality in statin users versus never users.

Hazard ratios are shown after multivariable adjustment, after additional adjustment for propensity score, and after multivariable adjustment with the use of Fine and Gray subhazard regression allowing for competing risk of death.

Fig 5. Risk of all-cause mortality in statin users versus never users stratified for covariates.

Hazard ratios are shown after multivariable adjustments. Year of diagnosis was divided into two periods, 1995–2003 and 2004–2009, as a consensus on classification of idiopathic lung fibrosis was published in 2002 [19].