Association between serum uric acid level and outcome in intensive care unit, an ancillary analysis of the FROG-ICU cohort (URIC-ICU).

Background: There is increasing evidence that elevated serum uric acid (SUA) levels are associated with increased risk of AKI. However, very little data is available on SUA levels in the ICU setting. We aimed at studying the level of SUA in ICU patients and its association with patient outcomes and incidence of acute kidney injury (AKI).

Methods: We conducted an ancillary study using the prospective FROG-ICU cohort. We selected patients with SUA measurement at inclusion. The primary endpoint was 90-day mortality. The secondary endpoints were 1-year mortality, occurrence of AKI, and MAKE at day 30. To better characterize the association between SUA and outcomes, we performed a propensity score matching analysis and a subgroup analysis of patients with unaltered glomerular filtration rate (GFR) at admission.

Results: A total of 1741 patients were included with a median SOFA score of 7 [5-10] and a median SUA value of 175 µmol/L [113-273]. Higher SUA at admission (>175 µmol/L) was significantly associated with 90-day mortality after adjustment, OR: 1.43 CI_95% [1.11-1.82], and with every secondary endpoint. This association remained significant after propensity score matching. The association between SUA and AKI and mortality was also significant in the subgroup of patients with unaltered GFR at admission.

Conclusions: Patients admitted to the ICU displayed a low level of SUA compared to the general population. Higher SUA level was associated with increased 90-day mortality, increased incidence of AKI, even among patients without altered GFR on admission, suggesting a possible role of uric acid in the worsening of renal function.

Study registration: ClinicalTrials.gov under number NCT01367093 (https://clinicaltrials.gov/study/NCT01367093?term = NCT01367093&rank = 1).