Edmonton Quality Assessment Tool for Drug Utilization Reviews: EQUATDUR-2: the development of a scale to assess the methodological quality of a drug utilization review.

OBJECTIVE

The objective of this study was to develop an instrument that will assist in evaluating the methodological quality of drug utilization reviews (DURs) and studies of prescribing appropriateness.

DESIGN

An expert committee followed accepted steps for developing and testing new instruments. Consultations on content, face validity, and scoring of items were solicited from external experts. Seven raters tested an initial version; subsequently, a refined instrument was designed. The Edmonton Quality Assessment Tool for Drug Utilization Reviews (EQUATDUR-2) evaluates 3 domains: sample selection (1 item), data collection (1 item), and data analysis (3 items). Sixteen raters tested EQUATDUR-2 on a random sample of DURs.

MEASURES

The study measures were reliability-using random effects interclass correlation coefficients for ratings by individual raters (ICC2,1) and the mean of ratings (ICC2,k)-and variability between DUR quality levels and rater groups.

RESULTS

There were significant differences in methodological quality (P <0.001) and in mean scores comparing low-, moderate-, and high-quality DURs. Nonmethodologists' ratings exhibited significant variability (P = 0.03) and tended to be higher. Agreement varied for individual items (ICC2,1, 0.22 to 0.44; ICC2,k, 0.81 to 0.91) and for mean summary ratings (ICC2,1, 0.42 [95% CI, 0.28 to 0.61]; ICC2,k, 0.92 [95% CI, 0.86 to 0.96]). The average time to rate each DUR was 10.0 minutes (95% CI, 9.2 to 10.9).

CONCLUSIONS

EQUATDUR-2 is a succinct, self-administered instrument with evidence of validity and reliability. We recommend that > or =2 raters independently assess each DUR and resolve disagreements by consensus. EQUATDUR-2 will help clinicians and decision makers to evaluate the quality of DUR studies and provide a framework for enhancing rigor in the design, conduct, and reporting of DURs.