Incidence and Outcome of Acute Kidney Injury In Hospitalized Children


 Background: Acute kidney injury (AKI) is now increasingly common in hospitalized children with adverse short and long term outcomes. The objective of this study is to know the incidence, etiology and short term outcome of AKI in developing nation.Methods: This prospective observational study is done in pediatric wards and pediatric intensive care unit (PICU) of tertiary center of eastern Nepal, between age group 2 months to 14 years. AKI is defined according to pRIFLE criteria.Results: From May 2015 to March 2016 942 patient enrolled in Pediatric wards and PICU are evaluated. The incidence of AKI was 5.9% and 21.76% in PICU. AKI was commonest among cases having infectious etiology compromising 73.2% (n=41), 16.1%(n=9) due to primary renal disease , 5.35%(n=3) secondary to congenital heart disease, and 5.35% due to other causes. Inotropes was required in 55.4% (n=31) cases, nineteen(33.9%)required mechanical ventilator while 3 (5.36%) underwent hemodialysis. Out of 56 AKI patients 71.4% (n=40) improved and 28.6% (n=16) expired. Patient with AKI had significant longer duration of hospital stay as compared to Non AKI (7 day vs 3 days , P< 0.001). Mortality was high in AKI patient who required mechanical ventilation, inotropes (p<0.001) and AKI Injury and Failure stage(p=0.003) .Conclusion: The incidence of AKI is high in pediatric patients. Patients with AKI increases the duration of hospital stay and mortality is more in patients requiring mechanical ventilation and inotropes.

Conclusion: The incidence of AKI is high in pediatric patients. Patients with AKI increases the duration of hospital stay and mortality is more in patients requiring mechanical ventilation and inotropes.

Background
Acute kidney injury (AKI) is associated with signi cant morbidity and mortality in hospitalized children (1). Studies of AKI in pediatric patients show that the causes and incidence of AKI depend on country's level of development, the hospital's level of complexity and the de nitions used. About 5% of all patients admitted to hospitals and 30% of those admitted to intensive care units develop acute kidney injury (AKI) and frequently need renal replacement therapy (2). Hospital and pediatric intensive care unit (PICU)acquired pediatric AKI (pAKI) rates appear to have increased due to increasing use of more invasive management and higher illness severity of critically ill children (3). Single-center studies from the 1980s and 1990s report hemolytic uremic syndrome (HUS), other primary renal causes, sepsis, and burns as the most prevalent causes leading to pAKI where as latest studies reveal a dramatic shift in the epidemiology of pAKI, with the most common causes being renal ischemia, nephrotoxin use, and sepsis (4). Recently a standardized AKI consensus de nition and staging was proposed by the Acute Dialysis Quality Initiative, namely, the RIFLE criteria (Risk, Injury, Failure, Loss, End-Stage Renal Disease). Patients with RIFLE class R were indeed at high risk of progression to class I or class F (5,7,8). Despite signi cant improvements in therapeutics, the mortality and morbidity associated with AKI remain high (6). In developing countries like ours we have limited data about incidence of AKI in hospitalized children. There is marked paucity of reports about etiology behind development of AKI as well as its outcome. Detection of the incidence, etiological pro le and outcome of AKI is important for starting preventive and therapeutic modalities (7).

Methods
This prospective observational study was carried out from May 2015 to March 2016 in Pediatric wards and PICU of B.P. Koirala Institute of Health Sciences, Dharan, Nepal, in children from 2 months to 14 years. The patients excluded were (i)children with chronic kidney disease( II) congenital renal anomaly (iii) known AKI at admission. The study is approved by Institutional review board of BPKIHS. Informed assent was taken from parents. Con dentiality of data was made.
Children admitted in paediatric ward or PICU were screened for the presence of AKI by using a predesigned screening form during a one year period, according to the criteria of the pRIFLE. Urine output was measured on patients who were on risk of AKI and those admitted in intensive care unit. The predesigned screening proforma included SIRS/sepsis, shock, dehydration, CCF and use of nephrotoxic agent as risk factor for development of AKI. Serum level of creatinine was estimated by autoanalyzer by modi ed Jaffes method at admission thereafter every 24 hr for critically ill children. In patient, who were not critically ill but having risk factor the level were determined at admission and every 48 hour till resolution.
The mean eCCl was taken as 120ml/min/1.73m 2. Patient having AKI were labelled as Risk, Injury, or Failure based on eGFR or urine output criteria whichever was severe according to pRIFLE scale. The progression of AKI was recorded along with treatment received during the management. eGFR (ml/min/1.73m 2 )was calculated by Schwartz formulas as shown(9). eGFR= k * length(cm)/serum creatinine(mg/dl) This study considered 95% con dence interval and 80% power for sample size estimation. According to literature review the incidence of AKI is 4-6%, taking incidence as 5% the sample size came out to be 860.
All the data collected were entered in MS excel and SPSS version 11.5 and used for data analysis.
Descriptive analysis: Percentage (%), Proportion, Mean, Median, Standard Deviation, Interquartile range, Range were calculated along with Graphical and tabular presentation were made. Chi square test was applied to nd out signi cant association between categorical data and. Mann-Whitney U test was applied for comparing nonparametric numerical data with categorical data. Kruskal-Wallis H test was applied for comparing hospital days according to pRIFLE scale. p value less than 0.05 was considered statistically signi cant.

Results
During the study period 942 patients admitted in pediatric ward and PICU ful lled the criteria and were evaluated. Out of 942 patient 56 patient develop AKI according to pRIFLE criteria accounting for 5.9%.
AKI was commonest among cases having infectious etiology compromising 73.2% (n=41), 16.1% (n=9) due to primary renal disease, 5.35%(n=3) secondary to congenital heart disease, and 5.35% due to other causes.   Mortality was high in AKI patient who required mechanical ventilation and inotropes which was statistically signi cant. Renal replacement therapy was provided to 3 patient ( 2 peritoneal dialysis and 1 hemodialysis) who were in failure. Two of the patients who went RRT were expired. The need of mechanical ventilation, Inotropes , PICU admission was higher in AKI injury and failure group which is statistically signi cant. The mortality in AKI in children too has been reported to vary widely from 16 % to 43.8 % [4,8,10,[16][17][18][19] According to literature the mortality of AKI varied from 14.5 to 37% with more mortality in critically ill patient (2,12,13). In our study mortality among AKI patient was 28.6 %( n=16  (12) The median duration of hospital stay was 9 (6-13) days for patients with AKI compared to 7 (5-10) days for those without AKI (P=0.02). Here total hospital length of stay was lower than other studies because mortality among cases which were in Injury or Failure was high. Though the hospital LOS increased from Risk to Injury and failure it wasn't statistically signi cant (p value 0.763). The length of stay also differed due to etiology of AKI. In our study patients with acute gastroenteritis who develop Injury and Failure, improved more quickly after correction of dehydration and length of stay was short.
The present study has some limitations. Only short term outcomes of study subjects were examined. Children with AKI may have long term residual renal injury. Neonates and infants upto 2 months were excluded in this study since their susceptibility and etiology of AKI is considerably different from older infants and children. Urine output criteria for de ning AKI were used only in the critically ill patient, and having prede ned risk factor may have led to under-reporting in the incidence of AKI. A potential limitation of our study is that it assumed a baseline creatinine clearance (eCCl) of 120 mL/min/1.73 m2 for all patients, as the baseline creatinine levels were unknown for most patients.

Conclusion
This prospective study provides data on the incidence of AKI in hospitalized children. Incidence of AKI is high in pediatric patient including non-critically ill children and associated with risk factors shock, sepsis and dehydration. Infectious etiology was the commonest cause of AKI followed by primary renal disease. They had longer duration of hospital stay and mortality was high among AKI patient who need mechanical ventilation, inotropes and AKI Injury and Failure.