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 (NCT0268216) 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 (FEV₁) 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.

Keywords:

• direct medical costs
• EQ-5D
• resource utilization
• utilities

Acknowledgments

Data within this manuscript were presented at the International Society for Pharmacoeconomics and Outcomes Research - 23rd International Meeting (poster: PRS19), the American Thoracic Society - 114th International Conference (poster: 10748), and at the European Respiratory Society International Conference 2018 (oral presentation). Editorial support (in the form of writing assistance, assembling tables and figures, collating author comments, grammatical editing and referencing) was provided by Emma Hargreaves and Elizabeth Jameson, PhD at Fishawack Indicia Ltd, UK, and was funded by GSK. This study was funded by GlaxoSmithKline (GSK; study number HO-16-16345). The funders of the study had a role in study design, data analysis, data interpretation, and writing of the report.

Abbreviation list

CI, confidence interval; CID, clinically important deterioration; CID+, with CID; CID-, without CID; COPD, chronic obstructive pulmonary disease; ED, emergency department; EQ-5D, EuroQol 5-dimensional scale; EuroQol, Euro quality-of-life; FEV₁, forced expiratory volume in 1 second; FP, fluticasone propionate; FVC, forced vital capacity; GBP, Great British Pounds; ICS, inhaled corticosteroid; ICU, intensive care unit; IPW, inverse probability-weighting; LABA, long-acting β₂-agonist; LAMA, long-acting muscarinic antagonist; mMRC, modified Medical Research Council; NHS, National Health Service; PPPY, per patient per year; QoL, quality of life; SAL, salmeterol; SGRQ, St George’s Respiratory Questionnaire; TORCH, TOwards a Revolution in COPD Health.

Ethics approval and informed consent

This article is based on a previously conducted study and does not involve any new studies of human or animal subjects performed by any of the authors. The study presented was an integrated post hoc analysis of a clinical trial conducted in accordance with the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use Good Clinical Practice guidelines and the principles of the Declaration of Helsinki. All participants provided written informed consent before participation in the studies considered in this analysis.

Data availability

The corresponding author had full access to all data. Anonymized individual participant data and study documents can be requested for further research from www.clinicalstudydatarequest.com.

Author contributions

All named authors meet the International Committee of Medical Journal Editors criteria for authorship for this manuscript, take responsibility for the integrity of the work as a whole, contributed to the writing and reviewing of the manuscript, and have given final approval of the version to be published. All authors had full access to all of the data in this study and take complete responsibility for the integrity of the data and accuracy of the data analysis. All authors were involved in the conception and design of the study and data analysis and interpretation. 

Disclosure

IN, NBG, and ASI are employees of GSK, and hold stock/shares in GSK. ASI is also an unpaid professor at McMaster University in Canada. MTD was employed by GSK at the time of this study. VFP and NR are employees of ICON Health Economics, who were contracted by GSK to conduct the study analysis. AB received consultancy fees from GSK and ICON Health Economics in relation to this study. AB and ICON employees were not paid for manuscript development. The authors report no other conflicts of interest in this work.

Supplementary materials

Table S1 Direct medical costs included in the CID analysis

Table S2 EQ-5D utility changes and health resource utilization by CID status