Acute kidney injury not associated with worsening of chronic kidney disease
Once researchers accounted for patient characteristics, such as prehospitalization estimated glomerular filtration rate (eGFR) slope and level of proteinuria, an episode of acute kidney injury in the hospital did not predict subsequent decline in eGFR.
An association between mild to moderate acute kidney injury (AKI) and later worsening kidney function in patients with chronic kidney disease (CKD) was small after other covariables were considered, a study found.
To determine whether AKI was independently associated with trajectory of subsequent kidney function, researchers conducted a multicenter prospective cohort study among 3,150 U.S. patients with CKD. AKI was defined as a 50% or greater increase in inpatient serum creatinine level from nadir to peak. Kidney function trajectory was assessed using estimated glomerular filtration rate (eGFR) based on serum creatinine level (eGFRcr) or cystatin C level (eGFRcys) at annual study visits. Results were published July 11 by Annals of Internal Medicine.
During a median follow-up of 3.9 years, 433 participants had at least one occurrence of AKI, mostly stage 1 or 2 (92%). These patients had decreases in eGFRcr (−2.30 mL/min/1.73 m2; 95% CI, −3.70 to −0.86 mL/min/1.73 m2) and eGFRcys (−3.61 mL/min/1.73 m2; 95% CI, −6.39 to −0.82 mL/min/1.73 m2) after AKI. However, in fully adjusted models, the decreases were −0.38 (95% CI, −1.35 to 0.59) mL/min/1.73 m2 for eGFRcr and −0.15 (95% CI, −2.16 to 1.86) mL/min/1.73 m2 for eGFRcys, so the confidence intervals included the possibility of no effect. Estimates of changes in eGFR slope after AKI determined by creatinine level (0.04 mL/min/ 1.73 m2 per year; 95% CI, −0.30 to 0.38 mL/min/ 1.73 m2 per year) or cystatin C level (−0.56 mL/min/ 1.73 m2 per year; 95% CI, −1.28 to 0.17 mL/min/1.73 m2 per year) also included the possibility of no effect.
The study authors concluded that based on the results, any independent association between mild to moderate AKI and more rapid subsequent CKD progression would be small, although they did note that there were few cases of severe AKI.
“Our results suggest that much of the kidney disease observed after AKI may already be present before AKI,” the researchers wrote. “Thus, efforts focused on ameliorating the effects of the AKI episode may have only a small effect on overall CKD burden. A better strategy may be to focus on flattening the eGFR slope and treating proteinuria before the AKI episode. However, a diagnosis of AKI does present an opportunity to identify high-risk patients and implement evidence-based interventions to slow CKD progression.”