High prevalence of unrecognized chronic kidney disease in the Lolland-Falster Health Study: a population-based study in a rural provincial area of Denmark

Chronic kidney disease (CKD) affects 10-15% globally and is a marked independent risk factor for cardiovascular disease. Prevalence estimations are essential for public health planning and implementation of CKD treatment strategies. This study aimed to estimate the prevalence and stages of CKD in the population-based Lolland-Falster Health Study, set in a rural provincial area with the lowest socioeconomic status in Denmark. Additionally, the study characterized participants with CKD, evaluated the overall disease recognition, including the awareness of CKD and compared it with other common conditions. Cross-sectional data were obtained from clinical examinations, biochemical analyses, and questionnaires. CKD was defined as albuminuria (urine albumin-creatinine ratio ≥30 mg/g), estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m², or by a diagnosis in the National Patient Register. Patient awareness was assessed by self-reported CKD, and overall disease recognition by either a registered hospital diagnosis or self-reported CKD. Among 16 097 adults (median age 58.6 years), CKD prevalence was 18.0% (n = 2903), with 70.1% identified by albuminuria, 28.4% by reduced eGFR, and 1.5% by a registered diagnosis alone. Of those with CKD, 98.8% had stages 1-3 (eGFR ≥30 ml/min/1.73 m²), and 1.2% had stages 4-5 (eGFR <30 ml/min/1.73 m²). Female sex, comorbidities, smoking, and low socioeconomic parameters were independently associated with CKD. Patient awareness of CKD was 4.4%, compared to >50% for hypertension and >80% for diabetes, and the overall CKD recognition (self-reported or registered diagnosis) was 7.1%. Thus, in this population-based study, CKD was highly prevalent but poorly recognized, indicating great potential for preventing CKD progression and related complications.