Geographic Variation of Endoscopic Sinus Surgery in Canada: An Alberta-Based Small Area Variation Analysis

Objective With an estimated 10,000 to 15,000 endoscopic sinus surgery (ESS) cases performed in Canada each year, identifying potential unwarranted practice patterns is important. The objective of this study is to examine the rates and geographic variation of ESS in the province of Alberta, Canada. Study Design Small area variation analysis. Setting Province of Alberta, Canada. Subjects and Methods The National Ambulatory Care Reporting System database was searched to identify all patients who received ESS between April 1, 2010, and March 31, 2013, in Alberta, Canada. The annual adjusted rates of ESS per 1000 people were calculated for each Alberta health zone and health status area. Geographic variations were evaluated with the extremal quotient, weighted coefficient of variation, and systematic component of variance. Chi-squared-test was used to quantify the significance of variation of the adjusted ESS rates across regions. Results The annual adjusted rate of ESS was 0.33 per 1000 people in Alberta, Canada. The mean extremal quotient for health status areas was 6.9, indicating a 7-fold difference between the highest and lowest regions. The mean coefficient of variation was 41.0, and the mean systematic component of variance was 10.5, which demonstrates very high variation. Conclusion This study observed very high geographic variation in the rates of ESS across the province of Alberta. Given the negative impact of unwarranted surgical variation on quality of care, outcomes from this study indicate a need to further evaluate the delivery of care for ESS in Canada to improve overall health system performance.