Development and validation of a case definition to estimate the prevalence and incidence of cirrhosis in pan-Canadian primary care databases

Aims: To develop and validate case definitions to identify patients with cirrhosis and alcohol-related cirrhosis using primary care electronic medical records (EMRs) and to estimate cirrhosis prevalence and incidence in pan-Canadian primary care database, between 2011 and 2019. Methods: A total of 689,301 adult patients were included with ≥1 visit to a primary care provider within the Canadian Primary Care Sentinel Study Network between January 1, 2017 and December 31, 2018. Subsample of 17,440 patients was used to validate the case definitions. Sensitivity, specificity, predictive values were calculated with their 95% confidence intervals (CI) and then determined the population-level prevalence and incidence trends with the most accurate case definition. Results: The most accurate case definition included: ≥1 health condition, billing, or encounter diagnosis for International Classification of Diseases, Ninth Revision codes 571.2, 571.5, 789.59, or 571. Sensitivity (84.6; 95% CI: 83.1–86.%), specificity (99.3; 95% CI: 99.1–99.4%), positive predictive values (94.8; 95% CI: 93.9–95.7%), and negative predictive values (97.5; 95% CI: 97.3–97.7%). Application of this definition to the overall population resulted in a crude prevalence estimate of (0.46%, 95% CI: 0.45%–0.48%). Annual incidence of patients with a clinical diagnosis of cirrhosis nearly doubled between 2011 (0.05%, 95% CI: 0.04%–0.06%) and 2019 to (0.09%, 95% CI: 0.08%–0.09%). Conclusions: The EMR-based case definition accurately captured patients diagnosed with cirrhosis in primary care. Future work to characterize patients with cirrhosis and their primary care experiences can support improvements in identification and management in primary care settings.