A Computable Phenotype for Autosomal Dominant Polycystic Kidney Disease

Background: A computable phenotype is an algorithm used to identify a group of patients within an electronic medical record system. Developing a computable phenotype that can accurately identify Autosomal Dominant Polycystic kidney disease (ADPKD) patients will assist researchers in defining patients eligible to participate clinical trials and other studies. Our objective was to assess the accuracy of a computable phenotype using ICD (International Classification of Diseases) 9 and 10 codes (ICD-9/10) to identify patients with ADPKD. Methods: We reviewed four random samples of approximately 250 patients based on ICD-9/10 codes from the EHR from the Kansas University Medical Center database: patients followed in nephrology clinics who had ICD-9/10 codes for ADPKD (Neph+), patients seen in nephrology clinics without ICD codes of ADPKD (Neph-), patients who were not followed in nephrology clinics with ICD codes for ADPKD (No Neph+), and patients not seen in nephrology clinics without ICD codes for ADPKD (No Neph-). We reviewed charts and determined ADPKD status based on internationally accepted diagnostic criteria for ADPKD. Results: The computable phenotype to identify patients with ADPKD who attended nephrology clinics has a sensitivity of 98.7% (95% confidence interval (95% CI); 96.4-99.7), and a specificity of 84.1% (95% CI; 79.5-88.1). For those who did not attend nephrology clinics the sensitivity was 97.1% (95% CI; 93.3-99.0), and a specificity was 82.0% (95% CI; 77.4-86.1). Conclusion: A computable phenotype using the ICD-9/10 codes can correctly identify most patients with ADPKD and can be utilized by researchers to screen healthcare records for ADPKD patient cohorts with acceptable accuracy.