Sponsorship-related outcome selection bias in published economic studies of triptans: systematic review.

Background: Economic studies funded by the pharmaceutical industry are more likely to report favorable results and recommendations for the sponsor's product than are studies funded by nonindustry establishments.

Purpose: To determine whether clinical outcome data obtained from the same meta-analyses are used differently in various economic studies of oral triptans and whether there is an association between the study sponsorship and the choice of clinical outcome measure.

Data Sources: Economic studies of triptans were identified by updating a previously published systematic review.

Study Selection: Twelve studies that used the same meta-analyses as the source of clinical outcome data were identified.

Data Extraction: Two independent reviewers extracted the essential data from the identified studies.

Data Synthesis: In the 12 appraised studies, 9 alternative measures of effectiveness were derived from the same meta-analyses. Eleven studies were industry-related, and in these the selected clinical outcome consistently favored the sponsor's product. Also the reported results suggested that the sponsor's product was more cost-effective than the competitors' products.

Limitations: The cost-effectiveness of triptans is dependent on both the definition of clinical effectiveness and the treatment-related costs. Only bias related to the selection of the clinical outcome measure has been taken into account in this review.

Conclusions: The results of published economic studies of triptans are conflicting and biased. There is a tendency to select clinical outcome measures that support the sponsor's product. This leads to concern about the possible poor applicability of these results in decision making.