#4177 PREVALENCE OF UNRECOGNIZED CHRONIC KIDNEY DISEASE IN THE LOLLAND-FALSTER HEALTH STUDY: A POPULATION-BASED STUDY IN A RURAL-PROVINCIAL AREA OF DENMARK
Authors: Mannheimer Ebba , Jørgensen Morten , Hommel Kristine , Kamper Anne Lise , Feldt-Rasmussen Bo , Hornum Mads 
Published: June 2023

Abstract

Background and Aims
In order to improve renal and cardiovascular outcome in patients with chronic kidney disease (CKD), it is important to identify patients with CKD in early stages of the disease. Given the asymptomatic nature of early-stage CKD, the majority of the CKD patients are living with an unrecognized condition. There is limited knowledge about the Danish prevalence of CKD stage 1-4. Moreover, previous studies have shown association between CKD and low socio-economic status. This study aims to increase the insights into prevalence and risk factors of CKD in a population living in a part of Denmark where income and life expectancy is below the national average.

Method
Data was derived from The Lolland-Falster Health Study (LOFUS) which is a population and household-based prospective cohort study at Lolland-Falster, a mixed rural-provincial area in Denmark. Data was obtained between 2016 and 2020 from questionnaires, clinical- and paraclinical evaluation. CKD was defined according to KDIGO classification (single test) as urinary albumin-to-creatinine ratio (UACR) &gt;30 mg/g and/or estimated glomerular filtration rate (eGFR) &lt;60 ml/min/1.73 m2. Univariate and multiple logistic regression models were used to evaluate potential risk factors for CKD.

Results
The study included 16,142 adult individuals. Characteristics of the population are reported in Table 1. The median age was 58.6 years (IQR 44.7-68.6) and 53% of the population were women. The overall CKD prevalence was 17.7% and was higher in women than in men (19.2% versus 16.0%, p-value &lt; 0.001). Of the 2856 participants with CKD, 71.1% had CKD based on elevated UACR, 19.0% had CKD based on reduced eGFR and 9.9% had CKD based on reduced eGFR combined with elevated UACR. Among the participants with CKD, 31.8% had CKD stage 1, 39.2% had stage 2, 28.0% stage 3, and 1.1% had CKD stage 4-5. Less than 2% (n = 207) of the total population had a self-reported kidney-related diagnosis which correspond to only 4.5% of the individuals with CKD identified in the study. Among those with CKD stage 3-5, more than 27% did not report any kidney-related diagnosis. In univariate analyses, female sex (OR 1.25, 95% CI 1.15 – 1.35), age above 55 years (OR 3.55, 95% CI 3.01 – 4.20), BMI &gt; 25 kg/m2 (OR 1.02, 95% CI 1.02 – 1.03), diabetes (OR 3.38, 95% CI 2.89 – 3.95), hypertension (OR 3.34, 95% CI 3.06 – 3.65), cardiovascular disease (OR 2.28, 95% CI 1.86 – 2.79) and current or former smoking (OR 1.27, 95% CI 1.17 – 1.39) were all risk factors for CKD. In a multiple regression analysis, all risk factors but BMI were independent risk factors for CKD.

Conclusion
CKD is common in the LOFUS cohort with a prevalence of nearly 18%. Less than 5% are aware of their condition and therefore our data indicate a high rate of unrecognized CKD. Comorbidities such as hypertension, diabetes, and cardiovascular disease are strongly associated with CKD. In contrast to earlier findings, overweight and obesity did not seem to increase the risk of CKD in our study, when adjusted for other comorbidities. Our findings could be used to develop strategies for early identification of CKD patients, particularly in populations living in socio-economically disadvantaged areas.