Abstract
Rationale: Clinical trials have demonstrated that nintedanib and pirfenidone slow lung function decline in patients with idiopathic pulmonary fibrosis (IPF); however, few studies have examined the association between chronic use of these antifibrotic medications and real-world outcomes, especially among veterans. This study aimed to determine treatment prevalence among newly diagnosed patients with IPF and to compare clinical outcomes and economic burden between patients who received and those who did not receive antifibrotic medications in the United States Veterans Health Administration (VHA) database.
Methods: Eligible adults in the VHA database had ≥1 IPF claim during 10/1/2014–9/30/2019 and no other interstitial lung diseases. Patients had continuous coverage ≥12 months before (baseline) and after (follow-up) the date of first nintedanib or pirfenidone prescription (index date); for untreated patients, the index date was randomly selected between the first IPF diagnosis date and end of the identification period. Antifibrotic prevalence was calculated as the proportion of patients with nintedanib or pirfenidone claims in each quarter of the study period. Demographics and baseline clinical characteristics were reported for treated vs untreated patients. Per patient per month (PPPM) healthcare resource utilization (HCRU) and costs were analyzed for the baseline and follow-up periods. Median time to death was compared using Kaplan-Meier curves. Adjusted generalized linear models estimated HCRU and costs and Cox proportional hazards models generated adjusted hazard ratios (HR) and 95% CIs.
Results: Of 4,459 patients, only 29% were treated. Compared with untreated patients (n=3,609), treated patients (n=850) were younger with a higher baseline frequency of IPF-related comorbidities (e.g., gastroesophageal reflux disease, obstructive sleep apnea). After adjusting for covariates, treated patients incurred higher total mean costs PPPM than untreated patients ($11,777 vs $2,459; P<0.0001). The mean numbers of pharmacy and outpatient visits for treated vs untreated patients were 3.20 vs 2.26 (P<0.0001) and 5.10 vs 3.94 (P<0.0001), respectively. Inpatient care utilization and costs were similar between groups. Compared with untreated patients, treated patients had significantly longer overall survival (1198 vs 923 days; P<0.0001) and a lower adjusted risk of death (HR: 0.69; 95% CI: 0.61–0.78).
Conclusions: Antifibrotic therapy prevalence was low among VHA enrollees with IPF. Compared with untreated patients, treated patients had a longer overall survival and a lower adjusted risk of death. HCRU and costs PPPM were higher among treated patients compared with untreated patients.
