Background and objectiveDiabetes mellitus is the leading cause of chronic kidney disease (CKD) in our country. The objective was to estimate the global prevalence and by health areas of CKD in the diabetic population of Extremadura. MethodsObservational, longitudinal retrospective study in the diabetic population attended in the Extremadura Health System in 2012−2014. A total of 90,709 patients ≥18 years old were studied. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI). The presence of CKD was was defined as follows: an eGFR <60ml/min/1.73m2 in a time period≥of three months or the presence of renal damage, as evaluated by an urine albumin-creatinine ratio (UACR) ≥30mg/g, with or without reduced eGFR, also in a time period ≥ of three months. ResultsThe overall prevalence of CKD was 15.6% (17.5% in women and 13.7% in men) and it was higher in the province of Cáceres (17.0%) than in Badajoz (14.8%, p<0.001), with the lowest prevalence in the Navalmoral de la Mata health area (13.0%) and the highest in Plasencia (17.8%, p<0.001). The prevalence of CKD defined without the need for confirmation of the sustainability of kidney damage or decreased eGFR was 26.1% (29.3% in women and 22.9% in men), which represents an overestimation of the prevalence of 67%. ConclusionsThe prevalence of CKD in Extremadura's diabetic population is lower than usually referred to and differs significantly between its health areas.