Prevalence and Incidence of Diagnosed Chronic Rhinosinusitis in Alberta, Canada.

Importance: Reported prevalence rates of chronic rhinosinusitis (CRS) range from 1% to 12% worldwide. To facilitate appropriate health service delivery and resource allocation, it is important to improve the estimated burden of CRS to the health care system. Objectives: To assess the prevalence and incidence of diagnosed CRS in Alberta, Canada, from the perspective of the health care system and to evaluate the 10-year temporal trend and geographic variation of diagnosed CRS. Design, Setting, and Participants: From provincial-wide physicians' claim data, a CRS cohort was identified using a validated case definition. The population at the midpoint (2008-2009) of the study period (2 925 930) was used as the reference. The crude as well as age- and sex-standardized incidence and prevalence rates were calculated. The age-specific incidence and prevalence by sex were also assessed in each study year. Small-area variation analysis was conducted using extremal quotient, weighted coefficient of variation, χ2 statistic, systematic component of variation, and empirical Bayes variance estimate. Results: Of the 2 925 930 individuals in the study at midpoint (2008-2009), 1 451 261 (49.6%) were women, and the mean (SD) age was 45 (17) years. From fiscal year 2004-2005 to fiscal year 2013-2014, the mean age- and sex-standardized incidence of diagnosed CRS was 2.5 (range, 2.3-2.7) per 1000 population. The estimated prevalence based on age-specific incidence varied between 18.8 (95% CI, 18.7-18.9) and 23.3 (95% CI, 23.1-23.5) per 1000 population during 2004-2005 to 2013-2014, and no obvious growing trend was found. There was high geographic variation in the diagnosed incidence and prevalence of CRS (mean systematic component of variation, 19.4 and 12.3, respectively). Conclusions and Relevance: Although the incidence and prevalence rates of diagnosed CRS were lower compared with earlier published estimates obtained from population-based survey analysis, outcomes from this study may more accurately reflect the disease burden of CRS to the health care system. Given that the prevalence of CRS within a single province is expected to be uniformly distributed, the large geographic variation in diagnosed CRS indicates a potential gap in quality of care and justifies further investigation into the reasons for the variation.

Utilization Patterns of Topical Intranasal Steroid Therapy for Chronic Rhinosinusitis: A Canadian Population-Based Analysis.

Importance: Practice guidelines have provided a strong recommendation for the daily use of topical intranasal steroid therapy for patients with chronic rhinosinusitis (CRS). Deficiencies in utilization of intranasal steroid therapy may represent a gap in quality of care. Objective: To evaluate the utilization patterns of topical intranasal steroid therapy for CRS in the Canadian population. Design, Setting, and Participants: Retrospective review of a Canadian population-based health care administrative database. A validated case definition for CRS was applied, and the utilization of topical intranasal steroid therapy within this cohort was quantified during the 2014-2015 fiscal year. Interventions: Intranasal steroid spray for CRS. Main Outcomes and Measures: Primary outcome was the rate (per 100 patients) and quantity (per patient) of intranasal steroid spray utilization in patients with CRS. Secondary outcome was the geographic variation in the rate and quantity of intranasal steroid spray utilization for CRS. Results: A total of 19 057 adult patients with CRS were evaluated. The overall rate of intranasal steroid spray utilization was 20.1 per 100 patients with CRS (3821 of 19 057). In the 3821 patients with CRS who used an intranasal steroid spray during 2014 to 2015, the mean quantity of utilization was 2.4 U (1 U = 1 bottle per month) per patient (9314 U divided by 3821 patients with CRS). There was large geographic variation in both the rate and quantity of intranasal steroid spray utilization (P < .001 for both comparisons). Conclusions and Relevance: Topical intranasal steroid therapy continues to be underutilized for patients with CRS. Given the negative impact of low-quality medical care, outcomes from this study indicate a need to further evaluate factors leading to the underutilization of a recommended treatment in patients with CRS to improve overall health system performance.

A validated case definition for chronic rhinosinusitis in administrative data: a Canadian perspective.

BACKGROUND: Pharmacoepidemiological research using administrative databases has become increasingly popular for chronic rhinosinusitis (CRS); however, without a validated case definition the cohort evaluated may be inaccurate resulting in biased and incorrect outcomes. The objective of this study was to develop and validate a generalizable administrative database case definition for CRS using International Classification of Diseases, 9th edition (ICD-9)-coded claims. METHODS: A random sample of 100 patients with a guideline-based diagnosis of CRS and 100 control patients were selected and then linked to a Canadian physician claims database from March 31, 2010, to March 31, 2015. The proportion of CRS ICD-9-coded claims (473.x and 471.x) for each of these 200 patients were reviewed and the validity of 7 different ICD-9-based coding algorithms was evaluated. RESULTS: The CRS case definition of ≥2 claims with a CRS ICD-9 code (471.x or 473.x) within 2 years of the reference case provides a balanced validity with a sensitivity of 77% and specificity of 79%. Applying this CRS case definition to the claims database produced a CRS cohort of 51,000 patients with characteristics that were consistent with published demographics and rates of comorbid asthma, allergic rhinitis, and depression. CONCLUSION: This study has validated several coding algorithms; based on the results a case definition of ≥2 physician claims of CRS (ICD-9 of 471.x or 473.x) within 2 years provides an optimal level of validity. Future studies will need to validate this administrative case definition from different health system perspectives and using larger retrospective chart reviews from multiple providers.

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.