Model-based evaluation of the long-term cost-effectiveness of systematic case-finding for COPD in primary care.

Introduction: 'One-off' systematic case-finding for COPD using a respiratory screening questionnaire is more effective and cost-effective than routine care at identifying new cases. However, it is not known whether early diagnosis and treatment is beneficial in the longer term. We estimated the long-term cost-effectiveness of a regular case-finding programme in primary care.
Methods: A Markov decision analytic model was developed to compare the cost-effectiveness of a 3-yearly systematic case-finding programme targeted to ever smokers aged ≥50 years with the current routine diagnostic process in UK primary care. Patient-level data on case-finding pathways was obtained from a large randomised controlled trial. Information on the natural history of COPD and treatment effects was obtained from a linked COPD cohort, UK primary care database and published literature. The discounted lifetime cost per quality-adjusted life-year (QALY) gained was calculated from a health service perspective.
Results: The incremental cost-effectiveness ratio of systematic case-finding versus current care was £16 596 per additional QALY gained, with a 78% probability of cost-effectiveness at a £20 000 per QALY willingness-to-pay threshold. The base case result was robust to multiple one-way sensitivity analyses. The main drivers were response rate to the initial screening questionnaire and attendance rate for the confirmatory spirometry test.
Discussion: Regular systematic case-finding for COPD using a screening questionnaire in primary care is likely to be cost-effective in the long-term despite uncertainties in treatment effectiveness. Further knowledge of the natural history of case-found patients and the effectiveness of their management will improve confidence to implement such an approach.
Competing Interests: Competing interests: KKC reports grants from Pfizer China, outside of the submitted work. RS reports personal fees from Boehringer Ingelheim, personal fees from GSK, personal fees from Chiesi, personal fees from Takeda, personal fees from Novartis, personal fees from Polyphor, grants from CSL Behring, grants from Talecris, and personal fees from Dyax, outside of the submitted work. AMT reports grants from Linde REAL fund, grants from Alpha 1 Foundation, non-financial support from GSK, non-financial support from Boehringer Ingelheim, personal fees and non-financial support from Chiesi and personal fees and non-financial support from AZ, outside of the submitted work. SJ, PA, REJ, KKC, MM KJ, RR, DF, SS, AD, BGC, RS, JGA and SG report grants from NIHR, during the conduct of the study. Other authors declare no competing interests.
(© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. Published by BMJ.)