The prevalence of chronic kidney disease in the general population in Romania: a study on 60,000 persons

Chronic kidney disease (CKD) is a major public health problem worldwide, due to its epidemic proportions and to its association with high cardiovascular risk. Therefore, screening for CKD is an increasingly important concept, aiming for early detection and prevention of progression and complications of this disease.

We studied the prevalence of CKD in the adult population of Iaşi, the largest county in Romania, based on the results of a national general health screening program from 2007 to 2008. The patients were tested for CKD with serum creatinine and urinary dipstick. We used two different methods to estimate the glomerular filtration rate (eGFR): the simplified Modification of Diet in Renal Disease (MDRD) and the CKD Epidemiology Collaboration (CKD-EPI) equations. Based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria, we defined CKD as the presence of either eGFR < 60 ml/min/1.73 m² and/or dipstick proteinuria. The classification of CKD by stage was also done according to the KDIGO criteria.

The study population included 60,969 people. The global prevalence of CKD was found to be 6.69% by the MDRD formula and 7.32% when using the CKD-EPI equation. The prevalence of CKD was much higher in women than in men: 9.09% versus 3.7%, by MDRD, and 9.32% versus 4.85%, by CKD-EPI. By age groups, the prevalence of CKD was 0.95% and 0.64% in persons aged 18–44 years old, 4.27% and 3.57% (45–64 years old), 13.36% and 15.34% (65–79 years old), and 23.59% and 34.56% (>80 years old), according to MDRD and CKD-EPI, respectively. By stages, the prevalence of CKD stage 3a (eGFR 59 to 45 ml/min/1.73 m²) was 5.72% by MDRD and 5.96% according to CKD-EPI, whereas the prevalence of stages 3b, 4, and 5 taken together (eGFR < 45 ml/min/1.73 m²) was 0.96% (MDRD) and 1.35% (CKD-EPI). Patients with CKD were significantly older (71.0 years versus 53.7 years) and had lower levels of serum Hb, total cholesterol, and glutamic pyruvic transaminase, and significantly higher serum creatinine and blood glucose, in comparison with the individuals without CKD. Impaired fasting glucose (106 mg/dl) was found in the CKD population, but not in non-CKD individuals.

Our study is one of the largest ever reported on the prevalence of CKD worldwide, the first one in Romania, and one of the very few of its kind in Europe (particularly in Eastern Europe). The study showed that the prevalence of CKD in our country is around 7%, which is lower than in other countries; however, this could be underestimated due to population selection bias. The prevalence is similar with the MDRD and the CKD-EPI equations; it increases with age and is much higher in women than in men. Impaired fasting glucose was detected in CKD patients, a finding that should probably raise the awareness of the high cardiovascular risk associated with CKD.