CKD in children

Chronic kidney disease (CKD) in children is defined as a kidney disease associated with reduced glomerular filtration rate (GFR). According to the reduction of GFR, it is divided into four stages, the last of which, terminal, require renal replacement therapy. The average incidence and prevalence of CKD in Serbia are 14.3 and 96.1 per million children, respectively. The most common causes of pediatric CKD are congenital kidney diseases. The main manifestations of untreated CKD are anemia, metabolic acidosis, growth retardation, arterial hypertension, and renal osteodystrophy. Treatment of CKD is expensive and requires a multidisciplinary approach. The most common causes of death are cardiovascular complications and infections. In terminal stage, the optimal replacement of kidney function is kidney transplantation.

Our results showed that prevalence of CKD stages 2–4 is 2.4 times greater that the prevalence of CKD stage 5. The actual proportion could be higher than the value we found as CKD is often asymptomatic in its early stages and therefore is underdiagnosed and underreported. Furthermore, it is certain, that our data underestimated the true morbidity of CRF in adolescents, as some of these patients maught be cared and followed by adult nephrologists. On the other hand, the prevalence rate for end stage renal disease (ESRD) patients in this study may be partially overestimated related to the addition of data from patients ages 20–24 to the prevalent group due to their longer follow up in pediatric center and delayed transfer to the adults centers. Turkish and Belgian authors reported even lower CKD 2-4/CKD 5 patients’ ratio (2.06 and 1.71 respectively). Nevertheless, the comparison of epidemiology of CRF in children is rather difficult due to the methodological differences in case definitions. With median annual incidence of 14.3 pmarp and point prevalence of 96.1.pmarp we are comparable to those reported by other European countries, such as France, Italy, Belgium, and Turkey.

Unlike to non-terminal CKD, ESRD is better defined and recognized. According to the data from literature, pediatric ESRD constitute only a few percent of the total ESRD patient population. In Serbia, adjusted incidence and prevalence rates of ESRD in adults in 2008 were 179.9 and 599.06 per million of total population (pmtp), respectively while in the same period corresponding number for children were 2.03 pmtp and 9.7 pmtp. Thus, pediatric ESRD constituted 1.6 % of the total ESRD patients in Serbia. Compared to the the data from other pediatric studies, with ESRD incidence of median 5.7 pmarp (IQR 4.2-9.4) Serbia belongs to the same category as the Netherlands (5.8 pmarp), Belgium (6.2 pmarp), and France (7.5 pmarp). The highest incidence rates for children were reported from the United States, New Zealand, and Austria, at 14.8, 13.6, and 12.4 per million population, respectively, while lowest was found in Japan. Median prevalence of CKD 5 of 62.2 pmarp (IQR 49.0-71.5) in this study is comparable to data from majority European countries as reported by ADR from the USRDS for 0–19 age group in 2003, but higher than the overall point prevalence (33.6 pmarp) for age group 0-14 in 2007, as recently reported by ESPN/ERA-EDTA.