Baseline characteristics and survival of patients of idiopathic pulmonary fibrosis: a longitudinal analysis of the Swedish IPF Registry

Abstract

Background Observational data under real-life conditions in idiopathic pulmonary fibrosis (IPF) is scarce. We explored anti-fibrotic treatment, disease severity and phenotypes in patients with IPF from the Swedish IPF Registry (SIPFR). Methods Patients enrolled between September 2014 and April 2020 and followed ≥ 6 months were investigated. Demographics, comorbidities, lung function, composite variables, six-minute walking test (6MWT), quality of life, and anti-fibrotic therapy were evaluated. Agreements between classification of mild physiological impairment (defined as gender-age-physiology (GAP) stage 1) with physiological and composite measures of severity was assessed using kappa values and their impact on mortality with hazard ratios. The factor analysis and the two-step cluster analysis were used to identify phenotypes. Univariate and multivariable survival analyses were performed between variables or groups. Results Among 662 patients with baseline data (median age 72.7 years, 74.0% males), 480 had a follow up ≥ 6 months with a 5 year survival rate of 48%. Lung function, 6MWT, age, and BMI were predictors of survival. Patients who received anti-fibrotic treatment ≥ 6 months had better survival compared to untreated patients [p = 0.007, HR (95% CI): 1.797 (1.173–2.753)] after adjustment of age, gender, BMI, smoking status, forced vital capacity (FVC) and diffusion capacity of carbon monoxide (DLCO). Patients with mild physiological impairment (GAP stage 1, composite physiological index (CPI) ≤ 45, DLCO ≥ 55%, FVC ≥ 75%, and total lung capacity (TLC) ≥ 65%, respectively) had better survival, after adjustment for age, gender, BMI and smoking status and treatment. Patients in cluster 1 had the worst survival and consisted mainly of male patients with moderate-severe disease and an increased prevalence of heart diseases at baseline; Cluster 2 was characterized by mild disease with more than 50% females and few comorbidities, and had the best survival; Cluster 3 were younger, with moderate-severe disease and had few comorbidities. Conclusion Disease severity, phenotypes, and anti-fibrotic treatment are closely associated with the outcome in IPF, with treated patients surviving longer. Phenotypes may contribute to predicting outcomes of patients with IPF and suggest the patients’ need for special management, whereas single or composite variables have some limitations as disease predictors.

The 1-minute sit-to-stand test to detect desaturation during 6-minute walk test in interstitial lung disease

“…However, the 6MWT is time-consuming and requires a 30 m corridor 12 , which is not common in primary care settings or clinical settings. In fact, even the Swedish IPF Registry, which was implemented in 22 respiratory medicine units across Sweden, reported that only 56% of patients underwent 6MWT 13 . Therefore, a simple exercise tolerance test is needed not only for general practitioners (GPs) but also for pulmonologists.…”

Combined Pulmonary Fibrosis Emphysema: Role of Cigarette Smoking and Pulmonary Hypertension in a Rural Cohort

“… 54 Longitudinal analysis of an IPF registry has shown an association of disease severity, based on physiological impairment and phenotypic clustering, to the outcomes of patients. 55 While adjusting for a similar UIP pattern between the groups, our multivariate analysis suggested BMI and pirfenidone as predictors of survival in addition to PH. It’s not surprising to observe lower BMI reduced survival in CPFE given its known association for poor prognosis in IPF and emphysema individual disease processes.…”

Mortality and survival in idiopathic pulmonary fibrosis: a systematic review and meta-analysis

“…Similar trend was found for the 5-year CSRs (patients taking antifibrotics: 51.4% [95% CI, 44.1-58.7; I 2 = 97.9%] vs. those taking non-antifibrotics: 43.9% [95% CI, 39.9-47.8; I 2 =93.4%]) (P=0.084). In addition, there were no significant associations between various diagnostic criteria and CSRs, and those associations remained consistent after exclusion of 16 studies [27,32,39,40,43,49,50,52,55,66,68,71,74,85,86,88] in which patients received antifibrotics (Table 4).…”