The quality of pharmacoeconomic evaluations of age-related macular degeneration therapeutics: a systematic review and quantitative appraisal of the evidence

Aim To appraise the quality of published pharmacoeconomic studies of therapeutic interventions for age-related macular degeneration (AMD). Methods Systematic review of the literature and evaluation of study quality using the Quality of Health Economic Studies instrument. A systematic search of the English-language literature for economic studies of therapeutic interventions for AMD from 1990 to March 2008 was performed. Results A total of 3637 articles were initially identified. Only 24 met eligibility criteria and were rated using the Quality of Health Economic Studies. The mean quality overall rating was 61.6, with quality scores ranging from 18 to 92. There was a higher mean quality score in the studies designed as clinical trials versus observational type designed studies (mean=74.7(11.4), 52.6 (16.5) respectively, p=0.002) and studies in which the statistical analyses were clearly presented versus studies in which the statistical analyses were not so clear (mean=74.3 (12.3), 53.1 (16.1) respectively, p=0.004). Interestingly, government funded studies exhibited a similar mean quality score to studies that were funded by industry (mean=71.0 (15.1), 61.7 (18.5) respectively, p=0.25). A general linear model was fitted using those independent variables which were significantly associated with quality score. The variables 'study design' and 'statistics presented clearly' were found to be jointly significant and explained nearly 70% of the variation in the dependent variable (R-2=0.68). Conclusions Our analysis reveals that the methodological quality of the health economic analysis of AMD therapeutic interventions in the literature is suboptimal. There is considerable variation in methodological rigour between the articles, and we have identified several attributes that are predictive of study quality.