Efficacy of initial high- versus low-dose intravenous corticosteroid therapy in patients with acute exacerbation of idiopathic interstitial pneumonia: A nationwide observational study.

Background: Acute exacerbation of idiopathic interstitial pneumonias (AE-IIPs) has a high mortality. However, there is no established treatment for AE-IIPs. Therefore, we aimed to compare the efficacy of high- and low-dose corticosteroid therapies in AE-IIPs patients.

Methods: Data were retrospectively collected from the Japanese Diagnosis Procedure Combination database from July 2010 to March 2018. Adult patients with AE-IIPs who received high-dose (methylprednisolone at a dose of 500-1000 mg/day for 3 days starting within 4 days after admission) or low-dose (methylprednisolone at a dose of 100-200 mg/day for at least 5 days starting within 4 days after admission) corticosteroid therapy were identified. Eligible patients (n = 17,317) were divided into the high-dose (n = 16,998) and low-dose (n = 319) groups. A stabilized inverse probability of treatment weighting using propensity scores was performed to compare outcomes between the groups.

Results: The primary outcome was in-hospital mortality, and the secondary outcomes were 28-day mortality, infections during hospitalization, length of hospitalization, duration of steroid use, and discharge to home. The in-hospital mortality rates of the high- and low-dose corticosteroid groups were 50.6% and 47.0%, respectively. In-hospital mortality did not significantly differ between the two groups after stabilized inverse probability of treatment weighting, and the odds ratio in the low-dose corticosteroid group was 0.86 (95% confidence interval: 0.64-1.16; p = 0.33). The secondary outcomes also did not significantly differ between the groups.

Conclusions: There was no significant difference in outcomes between patients with AE-IIPs who received high- and low-dose corticosteroid therapies.