Pediatric Acute Kidney Injury Cases Increased Tenfold Over Past 25 Years

Hospitalizations complicated by acute kidney injury (AKI) surged among patients in pediatric units or children’s hospitals over the past 25 years, a large retrospective study indicated.

Among more than 24.3 million discharges, hospitalizations involving AKI increased tenfold, rising from 15.7 per 10,000 discharges in 1997 to 168.7 in 2022. Rates of AKI requiring dialysis (AKI-D) more than doubled over the same period, growing from 2.4 to 5.5 per 10,000 discharges.

National weighted annual incidence of AKI cases jumped from 6,318 to 63,923, while AKI-D cases increased from 981 to 2,075, reported Alexander Kula, MD, MHS, of Ann and Robert H. Lurie Children’s Hospital of Chicago, and colleagues in JAMA Network Open.

However, in-hospital mortality among pediatric patients with AKI improved significantly, dropping from 1,814.0 to 643.4 per 10,000 hospitalizations between 2003 and 2022. Mortality for patients requiring dialysis remained stable at approximately 25%.

Rising AKI rates should not be viewed “solely as worsening care,” cautioned Laura Rangel Rodriguez, MD, of Cincinnati Children’s Hospital Medical Center, and David Selewski, MD, of Arkansas Children’s Hospital in Little Rock, in an accompanying commentary.

“Children with complex congenital heart disease, malignant neoplasms, transplants, and critical illness are surviving longer and being exposed to therapies and physiologic stressors that increase the risk of kidney injury,” they wrote. “Increasing AKI rates may therefore reflect both improved case identification and the growing medical complexity of contemporary pediatric hospital care.”

Kula’s team agreed that heightened recognition and coding changes partly explain the surge in AKI cases, though they noted this wouldn’t fully explain the rise in dialysis cases.

“The increase in AKI-D incidence may be a reflection of changes in the wider availability of dialysis devices and protocols suitable for infants or changes in physician practice patterns regarding willingness to initiate dialysis in increasing numbers of patients with AKI,” the researchers noted. “It could also be secondary to an increase in the severity of AKI stemming from an increase in disease severity, multiple organ dysfunction, and requirement for technology use in hospitalized pediatric patients.”

Implications of the findings go beyond hospitalization, Rangel Rodriguez and Selewski added. “Survivors of AKI and AKI-D face increased risks of chronic kidney disease, hypertension, recurrent AKI, and cardiovascular complications. Recognition of these long-term consequences has prompted increasing emphasis on post-AKI surveillance and longitudinal follow-up in children and neonates.”

Ultimately, healthcare systems must build sustainable approaches to patient education, transition planning, and outpatient nephrology care as the pool of AKI survivors expands, they advised.

“These challenges are further amplified by workforce shortages in pediatric nephrology and highlight the need for robust neonatal and pediatric critical care nephrology programs,” the editorialists added. “Ensuring adequate resources for pediatric critical care nephrology and neonatal critical care nephrology programs is critical to continue to move the bar in this field.”

For the study, the researchers analyzed data from the Healthcare Cost and Utilization Project Kids’ Inpatient Database (KID), a population-based sample of pediatric unit and children’s hospital admissions released every 3 years.

AKI and dialysis usage were identified using ICD-9-CM codes for KID releases from 1997 to 2012 and ICD-10-CM codes for releases from 2016 to 2022.

Across 24,344,876 included discharges, an estimated 253,138 hospitalizations were complicated by AKI. The estimated mean age was 6.9 years, and 46.9% were male.

In 1997, the three most common primary diagnoses among AKI hospitalizations were malignancy (7.5%), cardiovascular conditions (6.7%), and hematologic or immune conditions (2.2%). By 2022, the top primary diagnoses were cardiovascular conditions (3.3%), malignant neoplasms (2.4%), and complex medical technology dependence (1.3%).

Over time, a higher proportion of AKI-related hospitalizations occurred at large hospitals and academic teaching centers. Across all survey years, hospitalizations with AKI consistently had longer lengths of stay.

Because KID lacks patient-level tracking, some hospitalizations within a given survey year may represent readmissions of the same individual, the authors acknowledged as a study limitation.

“Future research should focus on testing the association of demographic and/or hospitalization covariables with AKI and AKI-D,” they concluded. “AKI should remain a priority for ongoing research and therapeutic innovation.”