Use of electronic health data for the identification of cases and for the evaluation of healthcare consumptions and chronic kidney disease costs

Introduction Chronic kidney disease (CKD) is a common condition characterized by a gradual loss of kidney function and consequently increasing costs associated with the disease. Aims The aim was to use administrative databases and a pathology registry to characterize CKD patient according to their stage and to evaluate the burden of disease; to identify incident patients on dialysis; to investigate the impact of COVID-19 on mortality in CKD patients. Methods Data from a regional pathology registry and administrative databases were used to classify CKD patients into different disease progression subgroups (CT-PIRP classification) using the following 6 variables: age, sex, diabetes, glomerular filtration rate, proteinuria, phosphate level and different CKD stages (3a, 3b, 4, 5). Healthcare consumptions and costs were evaluated. Incident chronic dialysis patients were defined those seen regularly in outpatient clinics. The incidence and mortality of COVID-19 among CKD patients were estimated. Results The study cohort includes 7737 CKD patients, aged 73.2±11.6 years, 64.5% males, mostly stage 4 (3136, 40.5%) and 3b (2799, 36.2%). Average annual costs were significantly higher for CT-PIRP groups 2 and 3 (€7239 and €8825 respectively) and more than twofold higher for CKD stage 5 (€7,993) compared to stage 3a (€3,973). Both algorithms used to identify incident chronic dialysis patients had high sensitivity, 90.8% and 88.4%, high positive predictive value (84.0% and 82.0%) and high agreement (77.4% and 74.1%). The incidence of COVID-19 infection was 4.16%. COVID-19 hospitalized patients were the 95.5%, those on home isolation were the 3.6% and the 0.9% were asymptomatic. Compared to those without COVID-19, the overall excess mortality ranged between 34.4% and 56.3%. Conclusion Administrative databases are a powerful tool to describe the burden of CKD disease, in order to assess the interventions aimed at reducing the impact of CKD and improving the quality of care of CKD patients.