Long-term cost and utility consequences of short-term clinically important deterioration in patients with chronic obstructive pulmonary disease: results from the TORCH study

Abstract

Purpose: Clinically important deterioration (CID) in chronic obstructive pulmonary disease (COPD) is a novel composite endpoint that assesses disease stability. The association between short-term CID and future economic and quality of life (QoL) outcomes has not been previously assessed. This analysis considers 3-year data from the TOwards a Revolution in COPD Health (TORCH) study, to examine this question.

Patients and methods: This post hoc analysis of TORCH (NCT00268216) compared costs and utilities at 3 years among patients without CID (CID-) and with CID (CID+) at 24 weeks. A positive CID status was defined as either: a deterioration in forced expiratory volume in 1 second (FEV ₁) of ≥100 mL from baseline; or a ≥4-unit increase from baseline in St George’s Respiratory Questionnaire (SGRQ) total score; or the incidence of a moderate/severe exacerbation. Patients from all treatment arms were included. Utility change was based on the EQ-5D utility index. Costs were based on healthcare resource utilization from 24 weeks to end of follow-up combined with unit costs for the UK (2016 GBP), and reported as per patient per year (PPPY). Adjusted estimates were generated controlling for baseline characteristics, treatment assignment, and number of CID criteria met.

Results: Overall, 3,769 patients completed the study and were included in the analysis (stable CID- patients, n=1,832; unstable CID+ patients, n=1,937). At the end of follow-up, CID- patients had higher mean (95% confidence interval [CI]) utility scores than CID+ patients (0.752 [0.738, 0.765] vs 0.697 [0.685, 0.71]; difference +0.054; P<0.001), and lower costs PPPY (£538 vs £916; difference: £378 [95% CI: £244, £521]; P<0.001). The cost differential was primarily driven by the difference in general hospital ward days ( P=0.003).

Conclusion: This study demonstrated that achieving early stability in COPD by preventing short-term CID is associated with better preservation of future QoL alongside reduced healthcare service costs.