Predictors of renal replacement therapy and mortality in children with chronic kidney disease

Objectives:

To study the epidemiology of chronic kidney disease (CKD) in children, and to look for risk factors to predict renal replacement therapy (RRT) and mortality.

Methods:

This is a retrospective cohort study conducted at King Abdulaziz University Hospital, Jeddah, Saudi Arabia between 2006 and 2014, where the files of 1,000 children with CKD were reviewed. We determined the effect of consanguinity and hypertension, and being a Saudi indigene on mortality and RRT. We compared children with congenital versus non-congenital causes of CKD.

Results:

The mean±standard deviation age at presentation was 4.9±4.3 years. The median duration of follow up was 1.5 (interquartile range [IQR]: 0.4-4.0) years. Only 9.7% of children received RRT, and 8.3% died. The underlying etiology for CKD was congenital in 537 children. The congenital CKD group presented at a younger age group (3.5±4.0 versus 6.6±3.9 years, p<0.0001), had more advanced stages of CKD (p<0.0001), higher rates of consanguinity (75.4% versus 47.1%, p<0.0001), and RRT (p<0.004) than children with non-congenital CKD. Risk factors for RRT among children with CKD include being a Saudi indigene (relative risk [RR]=1.49, 95% confidence interval (CI): 1.01-2.21), and hypertensive (RR=5.29, 95% CI: 3.54-7.91). The risk factor for mortality was hypertension (RR=2.46, 95% CI: 1.66-3.65).

Conclusion:

Congenital causes of CKD represent the main etiology of CKD in children living in the western province of Saudi Arabia. Significant risk factors for RRT include congenital CKD, Saudi nationality, and hypertension. Hypertension is also a predictor of mortality in children with CKD.Chronic kidney disease (CKD) is defined as abnormalities of kidney structure or function, present for more than 3 months with implications for health.1 Children with CKD who are on renal replacement therapy (RRT) have higher mortality rate, which is at least 30-fold higher than their age-matched peers.2 Epidemiological information on the incidence and prevalence of pediatric CKD in children is currently limited,3 particularly in developing countries. Furthermore, most of the available epidemiological data are from end-stage kidney disease (ESKD) registries, and information on the earlier stages of pediatric CKD is still lacking.4 The early stages of CKD in the pediatric population are in most cases asymptomatic, and are therefore under-diagnosed and under-reported.4 Direct comparisons of the incidence and prevalence rate of pediatric CKD are complex since each pediatric CKD registries uses different definition; some depend on the estimated glomerular filtration rate (eGFR), while others use serum creatinine levels. The incidence in Europe was consistent between 11-12 per million of the age-related population (pmarp) for CKD stages 3-5, and 8 pmarp for CKD stages 4-5.4 Data available on the exact prevalence of various kidney diseases in the Arab world is very limited. Most of the data come from small studies and are of limited generalizability.5 In Kuwait, the mean incidence was found to be as high as 38 pmarp, while the prevalence was as also high at 329 pmarp in 2003.6 An incidence of 11 pmarp and a prevalence of 51 pmarp has been reported in Jordanian children.7 The epidemiological data of CKD in children is very scarce in Saudi Arabia. One study from Asir reported that the mean annual incidence of CRF of 15.6 per million children, the mean annual incidence of ESRF is 9.2 per million children, and congenital anomalies of the urinary system constitute the most common cause of chronic renal failure (CRF).8 Another study from Jeddah reported similar results.9 All these studies enrolled a small number of children (less that 100). In the light of a limited data available regarding the epidemiology of CKD in children in Saudi Arabia, we performed a retrospective study to examine the risk factors for RRT and mortality among children with CKD.