Missed Opportunities for Chronic Kidney Disease Recognition in Irish Primary Care: A Nationwide Electronic Health Record Study

Objectives: To examine chronic kidney disease (CKD) diagnostic coding in Irish primary care using electronic health records (EHRs). Methods: This retrospective cohort study used EHR data from 592,888 active patients across 66 Irish primary care practices. Adults aged ≥20 years meeting laboratory-based CKD criteria were identified. CKD coding was defined by the presence of an ICD-10 or ICPC-2 diagnosis code. Coding rates were evaluated overall and by CKD stages, comorbidities, and practices. Results: Among 19,382 adults with laboratory-confirmed CKD (median age 76 years; 55.7% female), 14.6% had a documented CKD diagnosis code. Coding increased with disease severity, from 4.8% in stages 1-2 to 19.6% in stages 3-5, and varied by comorbidity burden, with only 10.1% of patients without major cardiometabolic comorbidities coded. Substantial practice-level variation was observed, with over half of practices (34/61) recording coding rates below 10%, while four exceeded 40%. Most patients (85.4%) remained uncoded throughout follow-up. Conclusions: This first nationwide study of CKD coding in Irish primary care network demonstrates substantial under-coding despite laboratory evidence, with marked variation between practices. Improving coding consistency and completeness may enhance CKD recognition, support earlier intervention, and improve patient outcomes.