Association Between Clinical Outcomes and Baseline Bmi or Annualized Weight Loss in Patients With Idiopathic Pulmonary Fibrosis Enrolled in the Pulmonary Fibrosis Foundation Patient Registry

Abstract

Low baseline body mass index (BMI) and weight loss have been linked with poor outcomes in patients with idiopathic pulmonary fibrosis (IPF). This analysis investigated the association between clinical outcomes and baseline BMI or annualized change in body weight in patients with IPF enrolled in the Pulmonary Fibrosis Foundation Patient Registry (PFF-PR). METHODS: This analysis examined the relationship between (a) BMI group at enrollment (<25 kg/m2, 25 to <30 kg/m2 or $30 kg/m2) or annualized percent change in body weight group (no loss, >0% to <5% or $5%) and patient baseline characteristics, (b) BMI group at enrollment and clinical outcomes and (c) annualized percent change in body weight group and clinical outcomes. Outcomes included all-cause mortality at 24 months as well as changes from baseline to 24 months in lung function and exercise capacity, as assessed by percent predicted forced vital capacity (%FVC) and percent predicted diffusing capacity for carbon monoxide (%DLCO). Regression analyses were conducted with adjustment for age, sex, smoking history, oxygen use during exertion, pulmonary function, significant comorbidities and medications (pirfenidone, nintedanib and corticosteroids). RESULTS: As of February 14, 2020, 696 patients with IPF from the PFF-PR were eligible for the analysis. At enrollment, pulmonary arterial hypertension (PAH) was the only comorbidity that varied across weight-change categories (P¼0.026), with 34 of 36 patients with PAH in the >0% to <5% annualized weight loss category. Logistic regression models did not indicate any difference in all-cause mortality between baseline BMI groups. Compared with patients with no weight loss, increased all-cause mortality was observed in patients with >0% to <5% and with $5% weight loss (odds ratios [95% CI], 5.4 [1.5, 34.4] and 5.4 [1.3, 36.9]). In the longitudinal analysis of %FVC and %DLCO, patients with baseline BMI <25 kg/m2 had a greater estimated annualized decline in %FVC than patients with baseline BMI $30 kg/m2 (difference [95% CI], 1.74% [0.47%, 3.0%]). A similar trend was also observed with %DLCO. There was no significant difference in annualized change of %FVC or %DLCO between groups defined by annualized percentage change in weight. CONCLUSIONS: Lower all-cause mortality was observed in patients with IPF with no annualized weight loss. Higher baseline BMI was associated with a lesser decline in lung function but not with lower all-cause mortality. CLINICAL IMPLICATIONS: Baseline BMI and annualized weight loss may be associated with clinical outcomes in patients with IPF.

Post hoc Analysis of Clinical Outcomes in Placebo- and Pirfenidone-Treated Patients with IPF Stratified by BMI and Weight Loss

“…Moreover, the rate of SAEs over 52 weeks was also numerically greater in placebo-treated patients with >5% weight loss versus ≤5% weight loss [25], similar to the results of our post hoc analysis. However, in contrast to our findings and the findings from a real-world registry [26], the rate of mortality in the INPULSIS studies was numerically lower in placebo-treated patients with >5% weight loss versus ≤5% weight loss [25].…”

“…Our findings expand on results from other studies that have assessed the relationship between BMI, weight loss, and outcomes in IPF [12][13][14][25][26][27]. A single-center cohort study that used bioelectrical impedance analysis found that BMI was independently associated with mortality in IPF [27], and US registry data identified a relationship between longitudinal reductions in BMI and risk of mortality [12].…”

“…Moreover, in the INPULSIS studies, the rate of FVC decline (mL/year) and worsening of SGRQ scores over 52 weeks were numerically greater in placebo-treated patients with >5% weight loss versus ≤5% weight loss [25], similar to the results of our post hoc analysis. The results from our post hoc analysis and the results from previous studies suggest that a BMI of <25 kg/m 2 and weight loss may be associated with worse clinical outcomes in patients with IPF [12][13][14][25][26][27].…”