Abstract BACKGROUND AND AIMS Acute kidney injury (AKI) affects up to one in five hospitalized patients and is independently associated with high morbidity and mortality. Additionally, patients have an increased risk for developing chronic kidney disease (CKD) after AKI. The combined impact of short- and long-term consequences and the high incidence of AKI results in a significant financial burden. Adequate intervention and follow-up might reduce the clinical impact of AKI, however the evidence for this remains inconclusive. The aim of this prospective cohort study was to evaluate whether nephrology consultation had an impact on patient follow-up and clinical outcome after AKI. METHOD All patients, admitted to VU medical centre in Amsterdam between October 2018 and April 2019, were screened for AKI by an automatic warning system integrated into the hospital's electronic patient record. This warning system sent a signal if serum creatinine would rise >27 µmol/L in 48 h or increased by a factor of at least 1.5 within 7 days (KDIGO criteria for AKI). The nephrology or internal medicine resident would then assess eligibility. Exclusion criteria were: a rise in serum creatinine that did not represent an actual AKI, admittance to the intensive care unit at the time of the signal, admission for kidney transplantation and patients that died before consultation was possible. After identification, nephrology consultation was provided. For the least severe AKI cases (KDIGO stage 1), this was done by telephone after review of the patient record, and for severe AKI cases (KDIGO stage 2 and 3) by full clinical review. Patients were grouped according to adherence (consult or no consult) to this protocol. Adequate follow-up was defined as a specific post-AKI referral to a nephrologist or general practitioner after hospital discharge. Recovery of serum creatinine and 6-month mortality were used as primary measures of clinical outcome. RESULTS A total of 371 cases of possible AKI were identified by the warning system. Of those case, 218 cases were eligible for inclusion. In 160 cases, nephrology consultation was performed (consult group). In 58 cases, there was no consult (no-consult group). The average age was 67.4 years. The consult and no-consult groups were similar at baseline (mean age, male/female, incidence of hypertension and diabetes), besides a higher incidence of CKD in the consult group (79% versus 64%; P = 0.034). The consult group had a significantly larger percentage of severe AKI cases (stage 2 or 3 in 29.4% of cases versus 12.1%; P = 0.021). Treatment was initiated in 93.1% of consult cases and in 70.6% of no-consult cases (P < 0.001) and there was a more profound decrease in the serum creatinine level from peak till 6 months (–33.7% versus –19.4%; P = 0.033)). All-cause mortality (34.1% versus 27.6%; P = 0.510), post-AKI follow-up (83% versus 73.2%; P = 0.116) and median serum creatinine value at six months (119 µmol/L versus 100 µmol/L; P = 0.334) did not differ between the consult and no-consult group. A 6-month serum creatinine was only available for 50% of cases in both groups. CONCLUSION When compared with cases of generally less severe AKI in which nephrology consultation was not performed, cases with nephrology consultation were associated with higher rates of treatment of AKI, faster recovery of kidney function and similar mortality. The data are in line with earlier non-randomized research which concluded that nephrology consultation can be linked to improved outcome in AKI. Before any definitive conclusions can be drawn, these associations should be found replicable in a randomized multi-centre setting and cost-effectiveness and feasibility should be analysed.