Economic Burden of Illness Among Commercially Insured Patients with Systemic Sclerosis with Interstitial Lung Disease in the USA: A Claims Data Analysis.

Introduction: Interstitial lung disease (ILD) is a common manifestation of scleroderma/systemic sclerosis (SSc). However, the direct and indirect economic burdens of SSc-ILD remain unclear. This study assessed and compared healthcare resource utilization (HRU), direct healthcare costs, work loss, and indirect costs between patients with SSc-ILD and matched controls with neither SSc nor ILD in the USA.

Methods: Data were obtained from a large US commercial claims database (2005-2015). Patients (at least 18 years old) had at least one SSc diagnosis in the inpatient (IP) or emergency room (ER) setting or at least two SSc diagnoses in another setting, and at least one diagnosis of ILD in the IP or ER setting or at least two diagnoses of ILD in another setting. Controls with neither SSc nor ILD were matched 5:1 to patients with SSc-ILD. Comparisons were conducted using Wilcoxon signed-rank and McNemar's tests and adjusted odds ratios (ORs) and incidence rate ratios (IRRs).

Results: A total of 479 SSc-ILD patients and 2395 matched controls were included (52 SSc-ILD patients and 260 matched controls for work loss and indirect cost analyses). Patients with SSc-ILD had significantly higher HRU and costs, IP admissions (adjusted IRR = 5.6), IP hospitalization days (adjusted IRR = 12.0), ER visits (adjusted IRR = 2.8), OP visits (adjusted IRR = 3.1), and days of work loss (adjusted IRR = 4.5). The adjusted difference in annual direct healthcare costs was $28,632 (SSc-ILD, $33,195; controls, $4562) and that in indirect costs was $4735 (SSc-ILD, $5640; controls, $906) (all p < 0.0001).

Conclusion: SSc-ILD patients had significantly higher HRU, work loss, and direct and indirect costs compared to matched controls with neither SSc nor ILD.

Funding: Boehringer Ingelheim Pharmaceuticals, Inc.