Impact of body weight change on clinical outcomes in patients with idiopathic pulmonary fibrosis receiving pirfenidone

Abstract

There have been limited studies on the association between prognosis and body weight change in patients with idiopathic pulmonary fibrosis (IPF). This single-center retrospective observational study evaluated the impact of weight loss on outcomes in Korean patients with IPF receiving pirfenidone at a tertiary medical institution. We analyzed 215 IPF patients prescribed pirfenidone from January 1st, 2015 to December 31st, 2019. The patients were categorized into maintained weight (MW; weight gain or loss < 5%/year) and reduced weight (RW; weight loss ≥ 5%/year) groups. The mean age was 71.8 years and 175 (81.4%) were male. There were 54 (25.1%) patients in the RW group. All patients showed a decrease in body weight (baseline vs. after 1 year; 64.1 kg vs. 62.8 kg, P < 0.001). Although baseline lung function showed a difference, there was no difference in the rate of change (forced vital capacity [% of predicted]; P = 0.221, diffusing capacity of the lung for carbon monoxide [% of predicted]; P = 0.973). The MW group had a lower risk of all-cause mortality (P < 0.001). Weight loss appeared to be a significant risk factor for mortality in patients with IPF. Not only disease control with antifibrotic agents, but also efforts to prevent weight loss may be necessary.

Figure 1

Flow diagram of the study population. IPF idiopathic pulmonary fibrosis, CTD connective tissue disease, ILD interstitial lung disease.

Figure 2

Linear mixed-effect model of pulmonary function trends. (A) Predicted mean FVC (mL) of body weight group with 95% CI. (B) Predicted mean FVC (% of predicted) of body weight group with 95% CI. (C) Predicted mean DLCO (mL/mmHg/min) of body weight group with 95% CI. (D) Predicted mean DLCO (% of predicted) of body weight group with 95% CI. P_Interaction analysis of interaction (type III) according to the two groups of body weight change (maintained weight vs. reduced weight) showed there was no interaction with time for each lung function change result. FVC (mL) P_interaction = 0.214, FVC (% of predicted) P_interaction = 0.221, DL_CO (mL/mmHg/min) P_interaction = 0.429, DL_CO (% of predicted) P_interaction = 0.973.

Figure 3

Time-to-event analysis of all-cause mortality, stratified by an annualized percentage change in body weight categories. Maintained weight group, preserved body or < 5%/year weight loss; Reduced weight group, ≥ 5%/year weight loss.