Clusters of comorbidities in idiopathic pulmonary fibrosis

INTRODUCTION: Comorbidities are common in patients with idiopathic pulmonary fibrosis (IPF) and negatively impact health-related quality of life, health-care costs and mortality. Retrospective studies have focused on individual comorbidities, but clusters of multiple comorbidities have rarely been analysed. This study aimed to comprehensively and prospectively assess comorbidities in a multicentre, real-world cohort of patients with IPF, including prespecified conditions of special interest and to analyse clusters of comorbidities and examine characteristics, disease course and mortality of the clusters.

METHODS: Several measurements, questionnaires, medications and medical history were combined to assess comorbidities. Using self-organizing maps, clusters of comorbidities were identified and phenotypes characterized. Disease course was assessed using mixed effects models and mortality using Cox regression.

RESULTS: One-hundred and fifty IPF patients were included prospectively. All except one patient suffered from at least one comorbidity and multimorbidity was common. Arterial hypertension, gastro-oesophageal reflux disease, hypercholesterolemia, emphysema and obstructive sleep apnea were most prevalent. Four comorbidity clusters were identified. Each cluster had distinct comorbidity profiles, patient characteristics, symptom burden and disease severity. Patients with fewer comorbidities had better exercise capacity and less dyspnea at baseline, but a trend towards faster deterioration was observed. Mortality analyses showed no significant differences between clusters.

CONCLUSIONS: Multimorbidity is prevalent in patients with IPF. Four specific clusters of comorbidities may represent phenotypes in IPF. A trend towards faster decline in exercise capacity and dyspnea was observed in patients with fewer comorbidities. Increased knowledge of comorbidities facilitates prevention and treatment of comorbidities in patients with IPF.