Intermediate and long-term AKI outcomes in a public health system.

Background: Acute Kidney Injury (AKI) is frequent and is associated with adverse outcomes.

Aims: To analyze the impact of community-acquired and hospital-acquired AKI on in-hospital and five-year post-discharge kidney replacement therapy (KRT) requirement in the pre-COVID era.

Methods: We linked the regional health system database of 419,851 admissions to the regional KRT registry. We grouped all admissions into 3 categories: community-acquired AKI, where AKI was the primary diagnosis, and hospital-acquired AKI, where AKI was an additional diagnosis alongside another primary condition. Admissions without this code were grouped into a third category (no AKI). We excluded patients aged under 18 years old, those with previous KRT, and pregnant women. The study was approved by the ethics committee. Patients were followed up for five years after discharge.

Results: Community-acquired AKI accounted for 0.6% of all admissions, associated prolonged average hospital stays, and increased mortality rates. In-hospital KRT administration was required in 3.1% of cases, and after a mean follow-up time of 459 days, 7.2% of these patients began chronic KRT. Hospital-acquired AKI represented 6.1% of all admissions and was associated with the highest mortality rate (22.9% vs 14.4% in the community-acquired AKI group) and the longest average hospital stay (12.6 days vs 7.1 in the no AKI group). Only 0.5% of hospital-acquired AKI cases required KRT during the AKI episode, while 2% of these patients initiated chronic KRT after a mean follow-up time of 594 days.

Conclusions: AKI continues to be a frequent problem in clinical practice, negatively influencing patient morbidity and mortality, and increasing the risk of starting KRT in the medium-long term.