Twenty years of real-world data to estimate chronic kidney disease prevalence and staging in an unselected population

Chronic kidney disease (CKD) represents a global public health burden, but its true prevalence is not fully characterized in the majority of countries. We studied the CKD prevalence in adult users of the primary, secondary and tertiary healthcare units of an integrated health region in northern Portugal (n = 136 993; representing ∼90% of the region’s adult population). Of these, 45 983 (33.6%) had at least two estimated glomerular filtration rate (eGFR) assessments and 30 534 (22.2%) had at least two urinary albumin:creatinine ratio (UACR) assessments separated by at least 3 months. CKD was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines as a persistent decrease in eGFR (<60 ml/min/1.73 m(2)) and/or an increase in UACR (≥30 mg/g). The estimated overall prevalence of CKD was 9.8% and was higher in females (5.5%) than males (4.2%). From these, it was possible to stratify 4.7% according to KDIGO guidelines. The prevalence of CKD was higher in older patients (especially in patients >70 years old) and in patients with comorbidities. This is the first real-world-based study to characterize CKD prevalence in a large, unselected Portuguese population. It probably provides the nearest estimate of the true CKD prevalence and may help healthcare providers to guide CKD-related policies and strategies focused on prevention and on the improvement of cardiovascular disease and other outcomes.