Body mass index and in-hospital mortality in patients with acute exacerbation of idiopathic pulmonary fibrosis

• Main Authors: Nobuyasu Awano, Taisuke Jo, Hideo Yasunaga, Minoru Inomata, Naoyuki Kuse, Mari Tone, Kojiro Morita, Hiroki Matsui, Kiyohide Fushimi, Takahide Nagase, Takehiro Izumo
• Format: Article
• Language: English
• Published: European Respiratory Society 2021-06-01
• Series: ERJ Open Research
• Online Access: http://openres.ersjournals.com/content/7/2/00037-2021.full

Background Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterised by chronic fibrosis, and acute exacerbation of IPF (AE-IPF) is the leading cause of death in patients with IPF. Data on the association between the body mass index (BMI) and prognosis of AE-IPF are lacking. This study was performed to evaluate the association between BMI and in-hospital mortality in patients who developed AE-IPF using a national inpatient database. Methods Using the Japanese Diagnosis Procedure Combination database, we retrospectively collected data of inpatients with AE-IPF from 1 July, 2010 to 31 March, 2018. We performed a multivariable logistic regression analysis to evaluate the association between all-cause in-hospital mortality and BMI, categorised as underweight (<18.5 kg·m−2), low-normal weight (18.5–22.9 kg·m−2), high-normal weight (23.0–24.9 kg·m−2), overweight (25.0–29.9 kg·m−2) and obese (≥30.0 kg·m−2). Results In total, 14 783 patients were eligible for this study. The in-hospital mortality rate was 59.0%, 55.0%, 53.8%, 54.8% and 46.0% in the underweight, low-normal weight, high-normal weight, overweight and obese groups, respectively. Underweight patients had a significantly higher mortality rate (OR 1.25, 95% CI 1.10–1.42) and obese patients had a significantly lower mortality rate (OR 0.71, 95% CI 0.54–0.94) than low-normal weight patients. Conclusion Among patients with AE-IPF, the underweight group had higher mortality and the obese group had lower mortality.