Low Baseline Creatinine Reduces the Likelihood of Nephrology Consultation in Stage 3 AKI

Background: Acute kidney injury (AKI) is common among hospitalized patients and significantly affects clinical outcomes. Previous studies suggest that inpatient nephrology consultation improves outcomes in patients with AKI. We analyzed consult rates for Kidney Disease: Improving Global Outcomes (KDIGO) stage 3 AKI to determine nephrology consult rates and to explore reasons for lack of consultation. Methods: This single-center, retrospective cohort study included adults admitted in 2019 with in-hospital KDIGO stage 3 AKI. Baseline creatinine was defined as the lowest creatinine within six months of admission. High nephrotoxin exposure was determined based on the current Nephrotoxic Injury Negated by Just-in-Time Action (NINJA) definition as ≥3 nephrotoxins on one day or ≥3 days of intravenous vancomycin or aminoglycoside. Patients were stratified into high and low baseline creatinine, and Chi-squared analysis was used to investigate rates of renal consultation, nephrotoxin exposure, and in-hospital mortality. Results: Among 634 patients with stage 3 AKI, the nephrology consultation rate was 54%. The most significant factor influencing consult rates was peak creatinine; 81% of patients with peak creatinine greater than the median of 3.25 mg/dL had a nephrology consultation compared to 27% of patients below the median (p<0.001). Similarly, 74% of patients with a baseline creatinine above the median of 0.7 mg/dL had a nephrology consult versus 38% less than the median (p<0.001). Females, elderly, and patients with a history of malignancy were statistically more likely to have baseline creatinine below the median. Neither rates of in-hospital mortality (25% vs. 23%, p=NS) nor high nephrotoxin exposure (32% vs. 35%, p=NS) were different in patients above and below median baseline creatinine. Conclusion: Rates of renal consultation were low among patients with stage 3 AKI (54%), and this was exacerbated in patients with a baseline creatinine of 0.7 mg/dL or below (38%), who were more likely to be elderly females. There was no significant difference between those above and below median baseline creatinine for in-hospital mortality or nephrotoxin exposure, suggesting that patients with low baseline creatinine and stage 3 AKI are an underrecognized patient subset with equally poor outcomes and equal need for nephrology consultation.