Register-based predictors of adherence among new statin users in Finland.

BACKGROUND: Although register-based studies on statin adherence are increasing, for administrative data, little is known about the explanatory power of the predictors that explain adherence. OBJECTIVE: The aim was to explore the ability of variables in administrative data to predict statin adherence in an unselected, universally insured population and, especially, to explore dispensation delay (time elapsed between prescription and dispensation) and out-of-pocket costs as explanatory factors. METHODS: Statin initiators who were aged 45 to 75 years in 2000-2004 (n = 247, 051) were identified in the Finnish Prescription Register. First-year statin adherence was measured as the proportion of days covered (PDC). The effect of variables related to patient, health care, and payment was assessed with multivariable logistic regression. The C statistic was used to evaluate the explanatory power of different models. RESULTS: Overall, 54.6% of the cohort had good adherence (PDC ≥ 80%). The explanatory power of all the models was low (C = 0.666 for the full model). The multivariable models, including only payment variables, had a greater explanatory power (C = 0.627) than models with only patient (C = 0.602) or health care (C = 0.548) variables. A shorter dispensation delay and lower out-of-pocket costs predicted better adherence. Of other patient-related variables, age, presence of acute coronary syndrome, and use of cardiovascular medications were significant predictors of adherence. Type of statin and the prescriber's workplace were also significantly associated with adherence. CONCLUSIONS: Models based on administrative data do not provide useful prediction of statin adherence. Of the individual predictors, long dispensation delay may serve as a practical tool for identifying patients at risk of poor adherence. Increases in out-of-pocket costs predict nonadherence.

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.