Association of constipation with the survival of patients with idiopathic interstitial pneumonias.

Background: Constipation is associated with the prognosis of several chronic diseases. However, the effect of constipation on the prognosis of idiopathic interstitial pneumonias (IIPs) remains unclear. This study aimed to investigate the association between constipation and the prognosis of patients with IIPs.

Methods: In this single-center, observational study, the association between constipation and survival of patients with IIPs was retrospectively investigated using a marginal structural model (MSM) analysis with weighting of age, sex, body mass index, treatment (corticosteroids, immunosuppressants, and antifibrotic agents), and pulmonary function (percent predicted forced vital capacity and diffusing capacity of the lungs for carbon monoxide).

Results: A total of 433 patients with IIPs (148 and 285 patients with idiopathic pulmonary fibrosis [IPF] and those without IPF) were included in the study. During the observation period, 238 patients developed constipation. The MSM analysis showed that constipation was significantly associated with shorter overall survival (hazard ratio [HR], 2.374; 95% confidence interval, 1.924-2.928, p < 0.001). When the use of antifibrotic agents was weighted separately as nintedanib or pirfenidone, constipation was significantly associated with shorter survival (HR, 2.427; 95% CI, 1.972-2.988, p < 0.001; and HR, 2.395; 95% CI, 1.940-2.957, p < 0.001, respectively). Furthermore, a subgroup analysis showed that constipation was associated with worse survival in patients with IPF and in those without IPF, regardless of the disease severity.

Conclusions: This study shows that constipation is an independent prognostic factor for patients with IIPs, suggesting its potential clinical utility.