Systematic Review of Cost-Effectiveness Research of Stroke Evaluation and Treatment

To the Editor: Holloway and colleagues’ review of cost-effectiveness studies in stroke evaluation and treatment 1 may have inadvertently introduced major biases by the selection criteria used for inclusion of studies. They decided to include only studies that used quality-adjusted life-years (QALYs) as the indicator of health effect. The justification for this criterion is not given. By doing this, cost-effectiveness studies that used indicators such as lives saved or strokes avoided are excluded, and the authors do not provide information on study exclusions to allow the reader to assess the potential bias created. The review is biased in two ways. First, the use of QALYs is inappropriate in many areas of stroke evaluation and management where measures of diagnostic accuracy, patient satisfaction, or reduction in symptoms are of relevance. It is noteworthy that the review excluded consideration of the most effective intervention for stroke management—organized stroke care and rehabilitation—for which reviews of cost-effectiveness studies have been performed. 2,3 Thus, the review is biased in describing the range of cost-effectiveness studies in stroke. Second, the review provides biased estimates of costeffectiveness. To illustrate this bias, consider the use of anticoagulation for patients with nonvalvular atrial fibrillation. The cost-effectiveness studies they present show that warfarin dominates among highand medium-risk patients but in low-risk patients has a very high cost per QALY. The authors concluded that anticoagulation was the preferred option for all but the low-risk patients. A cost-effectiveness study comparing anticoagulation only, anticoagulation or aspirin, or aspirin only that reported cost per stroke prevented was excluded but comes to remarkably different conclusions. 4 In this study, the cost per stroke prevented (which may arguably be a more relevant outcome than a QALY to most patients and doctors) was substantially lower for the aspirin-only regimen at US$1300 (Table). The most effective treatment is anticoagulation for those who can tolerate it and aspirin for the remainder, as this prevents 1300 strokes a year if complications are low, and even in complications are high still prevents more strokes than simply giving everyone aspirin— but this approach ignores the higher costs involved in anticoagulation. If complications of anticoagulation are high, which tends to be the case in older patients, the aspirin only policy is the most cost-effective option. I hope the authors of this review will consider updating it by using more appropriate inclusion criteria and thereby arriving at more relevant decisions to aid clinicians and policy makers.