The clinical and economic burden of systemic sclerosis related interstitial lung disease.

Abstract

To quantify the burden of interstitial lung disease (ILD) in SSc. Clinical data for SSc patients enrolled in the Australian Scleroderma Cohort Study were linked with healthcare databases for the period 2008-2015. ILD was defined by characteristic fibrotic changes on high-resolution CT (HRCT) lung, while severity was defined by the extent lung involvement on HRCT (mild <10%, moderate 10-30%, severe >30%). Determinants of healthcare cost were estimated using logistic regression. SSc-ILD patients utilized more healthcare resources, including hospitalization, emergency department presentation and ambulatory care services, than those without ILD with a total cost per patient of AUD$48 368 (26 230-93 615) vs AUD$33 657 (15 144-66 905), P<0.001) between 2008-2015. Healthcare utilization was associated with an annual median (25th-75th) excess cost per SSc-ILD patient compared with those without ILD of AUD$1192 (807-1212), P<0.001. Increasing ILD severity was associated with significantly more healthcare utilization and costs with an annual excess cost per patient with severe ILD compared with mild ILD of AUD$2321 (645-1846), P<0.001. ILD severity and the presence of coexistent PAH were the main determinants of overall healthcare cost above median for this SSc-ILD cohort (OR 5.1, P<0.001, and OR 2.6, P=0.01, respectively). Furthermore, SSc-ILD patients reported worse physical HRQoL compared with those without ILD [34.3 (10.5) vs 39.1 (10.8), P<0.001], with a progressive decline with increasing ILD severity (P=0.002). SSc-ILD places a large burden on the healthcare system and the patient through poor HRQoL in addition to incremental healthcare resource utilization and associated direct cost.