Background: Disease progression and acute exacerbations in patients with idiopathic pulmonary fibrosis (IPF) are associated with high morbidity and mortality. They usually require a visit to a specialist or a general practitioner (GP) in less severe cases or hospitalisation in more severe cases.
Objective: The objective of this study was to identify factors that influence resource use in IPF.
Methods: Clinical and healthcare resource use data were collected in two large, international, multi-centre, randomised controlled trials (RCTs) that studied nintedanib for the treatment of IPF (INPULSIS-1 and -2). The pooled data of nintedanib and placebo included 1014 patients followed for 12 months. The trial data were analysed in 3-month intervals. We studied two dependent variables: the occurrence of all-cause hospitalisation and visits to a physician (GP or specialist). The independent variables included the change in forced vital capacity percent predicted (FVC%pred), investigator-reported acute exacerbation events, age, time since diagnosis, smoking status, and sex.
Results: Hospitalisation during a 3-month interval was significantly associated with a drop of at least 5 or 10 points in FVC%pred (odds ratios [ORs] 1.58 [p = 0.009] and 2.62 [p < 0.001]) and associated with the occurrence of at least one acute exacerbation (OR 14.44; p < 0.001) during the same interval. The above factors remained significant when repeating the analysis for hospitalisation based on change in FVC%pred or events occurring during the previous 3 months interval. Smoker status and a unit change in FVC%pred during the previous interval were added to the significant factors. Physician visits during a 3-month interval were significantly associated with a lower FVC%pred at the start of the interval (per 10-point decrement, OR 1.05; p = 0.040) and with the change in FVC%pred during the same interval (per 10-point loss, OR 1.13; p = 0.042). Visits were also associated with a 5-point drop in FVC%pred (OR 1.23; p = 0.020), age (per 5-year increments OR 1.07; p = 0.028), and female sex (OR 1.32; p = 0.017). Nevertheless, the predictive power of the models was considered poor for both outcomes (hospitalisation and physician visits).
Conclusions: Disease progression and acute exacerbation events are significantly associated with hospitalisation of patients with IPF. Outpatient visits to physicians are associated with disease progression, baseline FVC%pred, age and sex.