Health care utilization and costs associated with acute exacerbation of fibrosing interstitial lung disease in the United States: A retrospective administrative claims database analysis.

Abstract

Interstitial lung disease (ILD) is a diverse group of pulmonary disorders characterized by inflammation and fibrosis of the lung parenchyma. Previous studies have linked acute exacerbation (AEx) events in patients with idiopathic pulmonary fibrosis to frequent hospitalizations, increased health care resource utilization (HCRU), and high mortality. However, limited information exists regarding the impact of AEx in other forms of fibrosing ILD. To assess HCRU and the associated costs of managing AEx in patients within a large population of patients with fibrosing ILD. This retrospective cohort study used a large US claims database to identify adults (aged ≥18 years) with fibrosing ILD who experienced at least 1 AEx event between January 2017 and September 2022. AEx events were identified using an algorithm based on clinical guidelines, symptoms, imaging, and prescriptions. Using propensity score matching, patients with AEx were matched to those without AEx. Baseline data were evaluated for 12 months before the date of first AEx or assigned proxy equivalent (index date), with follow-up until death, loss to follow-up, or study conclusion. Outcomes included health care costs, inpatient stay frequency and length, emergency department and outpatient visits, and prescriptions. Two-part regression models compared health care utilization and costs during follow-up. A total of 8,929 patients were identified as having at least 1 qualifying AEx event. After matching for clinical and demographic characteristics, 8,104 were retained in both the AEx and comparator cohorts (average age, 63 years; average Charlson Comorbidity Index, 8.18-8.33). An evaluation of postmatch baseline characteristics indicated cohorts to be well-balanced. Patients were followed for a mean of 616 days in the AEx group and 648 days in the comparator group. Regression analysis found all-cause inpatient HCRU to be 53% (risk ratio [95% CI] = 1.53 [1.45-1.62]) and outpatient HCRU to be 13% (risk ratio 1.13 [1.09-1.17]) higher for AEx cohort patients. For ILD-related utilization, the inpatient and outpatient rates were 98% and 63% higher, respectively, in the AEx cohort. Total per-patient per-month health care costs were $17,549 for AEx and $11,715 for comparator cohorts (<i>P</i> < 0.001). Per-patient per-month outpatient pharmacy costs were not significantly different between the cohorts ($1,327 vs $1, 302). This study found that patients with ILD experiencing AEx events incur significantly greater health care utilization and total costs than matched patients without AEx events. This study fills a key gap in understanding the broader health care burden of AEx beyond idiopathic pulmonary fibrosis.