Hospital cost and length of stay in idiopathic pulmonary fibrosis

Objective: To provide a detailed picture of the economic impact of hospitalization in idiopathic pulmonary fibrosis (IPF) and to identify factors associated with cost and length of stay (LOS). Methods: In this retrospective cross-sectional study using the Nationwide Inpatient Sample (NIS), this study included hospitalizations for IPF (ICD-9-CM 516.3) with a principal diagnosis of respiratory disease (ICD-9-CM 460-519) from 2009-2011; lung transplant admissions were excluded. Total inpatient cost, LOS, in-hospital death, and discharge disposition were reported. Linear regression models were used to determine variables predictive of LOS and cost. Results: From 2009-2011, 22,350 non-transplant IPF patients with a principal diagnosis of respiratory disease were admitted: mean (SE) age was 70.0 (0.32), and 49.1% were female. While in hospital, 11.4% of patients received mechanical ventilation and 8.9% received non-invasive ventilation. Mean (SE) LOS was 7.4 (0.15) days overall (p<.001). The mean (+/- SD) admission cost was $16,042 (+/- 631). Of hospitalized patients, 14.1% died, 20.6% transferred facilities, and 46.4% were routinely discharged. The adjusted LOS (95% CI) for patients with and without mechanical ventilation was 16.1 days (15-17.5) vs. 6.3 (6-6.5); adjusted costs were $48,772 (43,979-53,565) vs. $11,861 (11,292-12,431). Limitations: The positive predictive value of the algorithm used to identify IPF is not optimal. The NIS database does not follow patients longitudinally, and claims after admission are not available. Claims do not indicate whether listed diagnoses were present on admission or developed during hospitalization. The exclusion of transplant-related expenditures lead to under-estimation of cost. Conclusion: Using a nationally-representative database, we found IPF respiratory-related hospitalizations represent a significant economic burden with similar to 7,000 non-transplant IPF admissions per year, at a mean cost of $16,000 per admission. Mechanical ventilation is associated with statistically significant increases in LOS and cost. Therapeutic advances that reduce rates and costs of IPF hospitalizations are needed.