Increasing frequency of acute kidney injury amongst children hospitalized with nephrotic syndrome

Abstract

Background: Nephrotic syndrome (NS) is among the most common kidney diseases seen in children. The major complications of NS include infection, acute kidney injury (AKI), and thromboembolism (TE). The objective of this study was to analyze long-term trends in the epidemiology of major complications of pediatric NS.

Methods: We used the Healthcare Cost and Utilization Project Kids' Inpatient Database for the years 2000-2009 to perform an analysis of U.S. hospitalizations of children diagnosed with NS with or without infection, AKI or TE.

Results: The frequency of NS hospitalizations complicated by AKI increased by 158 % between 2000 and 2009 (p < 0.001). The frequency of NS hospitalizations with infection and TE remained stable overall. Pneumonia was the most common infectious complication while peritonitis decreased by 50 % (p < 0.001). Importantly, development of any of these major complications of NS resulted in ∼2-3-fold increases in both hospital charges and length of stay.

Conclusions: It is concerning that the frequency of AKI in children hospitalized with NS has more than doubled in the past decade. Strategies to prevent or initiate earlier treatments for complications of NS could have a major impact on both morbidity and health care expenses.

Fig. 1

Infections are the most common acute complication among pediatric nephrotic syndrome (NS) hospitalizations in the US, but acute kidney injury (AKI) is increasingly common. We used logistic regression to analyze trends in frequency of hospitalizations of (NS) with all complications, NS with infection, NS with acute kidney injury (AKI), and NS with thromboembolism (TE). The frequency of hospitalizations for NS with any complication went from 20.8 % in 2000 to 22.3 % in 2009 (p=0.11), with AKI increasing from 3.3 % in 2000 to 8.5 % in 2009 (p<0.001*). The frequency of NS hospitalizations complicated by infection (p=0.11) and TE (p=0.8) remained stable

Fig. 2

Trends in the frequency of common infections in pediatric nephrotic syndrome (NS) hospitalizations. We used logistic regression to analyze trends in frequency of NS hospitalizations with specific infections. The most common infectious complication of NS was pneumonia, followed by bacteremia/sepsis, peritonitis, UTI, and cellulitis. The frequency of NS hospitalizations with peritonitis decreased from 5.0 % in 2000 to 2.5 % in 2009 (p<0.001*). The proportion of infections due to pneumonia (p=0.47), bacteremia/sepsis (p=0.39), UTI (p=0.47), and cellulitis (p=0.38) was stable

Fig. 3

Acute kidney injury (AKI) is increasingly prevalent among toddlers, children, and adolescents hospitalized for nephrotic syndrome (NS) in the US. We analyzed the frequency of NS hospitalizations with AKI by age and also analyzed their trends using logistic regression. From 2000 to 2009, the frequency of NS hospitalizations complicated by AKI in 1–5 year olds increased significantly from 1.8 to 3.4 % (p=0.03*), from 3.0 to 7.8 % (p=0.02**) in 6–9 year olds, and 4.2 to 13.1 % (p=<0.001***) in 10–18 year olds. The frequency of AKI in children <3 months (p= 0.81) and 3–12 months (p=0.28) hospitalized with NS, did not change over the study period