Respiratory comorbidities and risk of mortality in hospitalized patients with idiopathic pulmonary fibrosis.

BACKGROUND

Respiratory comorbidities are frequently associated with idiopathic pulmonary fibrosis (IPF). However, little is known about their prognostic impact in hospitalized patients with IPF. We examined the impact of respiratory comorbidities on the mortality rates of hospitalized patients with IPF using a Japanese nationwide database.

METHODS

We identified 5665 hospitalized patients diagnosed with IPF between April 2010 and March 2013. The primary outcome was defined as the in-hospital mortality at 30 days after admission. The impact of respiratory comorbidities was assessed using a Cox proportional hazards model that incorporated clinically relevant factors.

RESULTS

In hospitalized patients with IPF, the prevalence of bacterial pneumonia, pulmonary hypertension, and lung cancer were 9.5%, 4.6%, and 3.7%, respectively. Among patients with bacterial pneumonia, the four most common pathogens were Streptococcus pneumoniae (31.6%), methicillin-resistant Streptococcus aureus (18.4%), Klebsiella pneumoniae (9.2%), and Pseudomonas aeruginosa (9.2%). Lung cancer was more commonly found in the lower lobes (60.1%) than in other lobes. The survival at 30 days from admission was 78.4% in all patients and significantly lower in IPF patients with bacterial pneumonia (adjusted hazard ratio [HR], 1.30; 95% confidence interval [CI], 1.04-1.63; p < 0.023) and patients with lung cancer (adjusted HR, 1.99; 95% CI, 1.47-2.69; p < 0.001) than in others. Pulmonary hypertension was not associated with mortality. IPF patients with one or more of these three respiratory comorbidities had a poorer survival than others (p < 0.05).

CONCLUSIONS

Respiratory comorbidities, especially bacterial pneumonia and lung cancer, influence mortality in hospitalized patients with IPF.