PP208 - 24-HOUR URINARY MINERAL EXCRETION AT INTENSIVE CARE UNIT ADMISSION AND LENGTH OF STAY

PP208

24-HOUR URINARY MINERAL EXCRETION AT INTENSIVE CARE UNIT ADMISSION AND LENGTH OF STAY

M. Galvis Pedraza^1,*, T. van Zutphen¹, I. J. Riphagen², H. Buter³, L. F. Beumeler⁴, E. C. Boerma¹

¹Department of Sustainability & Wellbeing, Faculty Campus Fryslân, University of Groningen, ²Certe Medical Diagnostics & Advise, Certe Medical Diagnostics & Advise, ³Department of Intensive Care, Frisius Medical Center, ⁴Research Group Digital Innovation in Healthcare and Social Work, NHL Stenden University of Applied Sciences, Leeuwarden, Netherlands

Rationale: Micronutrient disturbances are common in intensive care unit (ICU) patients. Urinary mineral excretion may reflect early metabolic and renal responses in ICU settings, but its association with ICU length of stay (LOS) remains unclear. We aimed to assess whether 24-hour urinary mineral excretion at ICU admission is associated with ICU LOS, independent of systemic inflammation.

Methods: Exploratory analysis of 79 adults admitted to a mixed ICU at a tertiary teaching hospital in the Netherlands. Twenty-four-hour urinary sodium and potassium were quantified by ion-selective electrode analysis; calcium, magnesium and inorganic phosphate were colorimetrically measured during ICU admission. ICU LOS was recorded in hours. Descriptive statistics were applied. Data were analysed using a reduced negative binomial regression model adjusted for C-reactive protein (CRP); predictors were standardised per 1 SD.

Results: Median 24-hour urine excretion (mmol/24 hour) was 55 [39 - 69] for sodium, 66 [57 - 79] for potassium, 1.8 [1.1 – 3.0] for calcium, 27.0 [24.5 – 33.0] for inorganic phosphate and 4.33 [3.63 – 6.23] for magnesium. In the adjusted model, higher 24-hour urinary potassium excretion was associated with shorter ICU LOS (rate ratio [RR] 0.72, 95% CI 0.55 – 0.95; p = 0.019). The excretion of magnesium showed a similar inverse association (RR 0.77, 95% CI 0.59 – 1.00, p = 0.050). Associations for remaining minerals were not statistically significant. CRP was positively associated with ICU LOS (RR 1.42, 95% CI 1.17 – 1.74; p < 0.001).

Conclusion: The mineral excretion over 24-hours at ICU admission showed selective associations with ICU LOS after adjustment for CRP. Higher urinary potassium excretion was associated with shorter ICU stay, with a weaker pattern for magnesium, suggesting that early renal handling of some minerals may reflect clinically relevant underlying processes in critical illness.

Disclosure of Interest: None declared