Interventions:
Both programmes were clearly and comprehensively reported. It was not clear whether the open programme was supposed to reflect standard diagnosis practice. Standard practice would have been the most appropriate comparator to adopt to accurately determine the cost-effectiveness of a new alternative. Other potential diagnosis programmes were discussed, in particular an approach from the UK that used a nurse-led community respiratory assessment unit offering spirometry and diagnostic support for primary care physicians. The authors stated that such an approach was not feasible in all settings.
Effectiveness/benefits:
The study reported positive predictive values (the percentage of participants who received spirometry that actually had the disease). There was no information on disease status on those that did not receive spirometry. The authors highlighted the problem of not accounting for false negatives, but stated that this would be more of a problem in the open programme since physicians were not specifically trained in that group. No evidence was supplied to support this assumption. A strategy that has a high positive predictive value may not necessarily result in a high detection rate, as many disease positive patients may be missed. In this case, more patients with the disease were identified through the open programme than the case-finding programme. Given the study data, from a cost-effectiveness point of view, the incremental cost per extra person identified with the disease was of interest. Ideally, information should be available on those who received spirometry and those who did not; the total health outcomes following treatment or no treatment for the population for the different screening strategies could be determined.
Costs:
The cost categories and results were clearly reported. The price year was not reported. The authors did not discuss the use of any cost-adjustment methods. The costs (and benefits) were not discounted, which was reasonable given the short time horizon.
The authors stated that the modest cost of approximately EUR 100 per new diagnosis of COPD had to be considered against the extreme costs of advanced disease, which may be avoided through early intervention. A thorough full economic evaluation would estimate the long-term outcomes, both health and health-care costs, from the different screening programmes for the population targeted. This would account for those identified and not identified, treated and not treated.
Analysis and results:
The diagnosis results were adequately reported and average cost for a diagnosis was reported, but it would have been useful to report the total costs per screening programme so that they could have been compared with the increase in the number of people identified as having the disease. Uncertainty around the diagnosis results were presented. The authors remarked that a possible limitation of their study was the fact that the findings may not have been generalisable, since they reflected local conditions applying to their specific setting.
Concluding remarks:
The outcomes of the study were inappropriate to measure the cost-effectiveness of the different screening programmes. The authors' conclusions should be used with caution.