Elevated Blood Urea Nitrogen and Medical Outcome of Psychiatric Inpatients
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- Manu, P., Al-Dhaher, Z., Khan, S. et al. Psychiatr Q (2014) 85: 111. doi:10.1007/s11126-013-9274-2
Elevated blood urea nitrogen (BUN) is associated with increased severity of illness and mortality, but its predictive value has not been studied in patients admitted to free-standing psychiatric hospitals. To determine the clinical outcome of psychiatric inpatients with elevated BUN on admission and to create a quantitative method of using BUN for predicting deteriorations requiring transfers of psychiatric inpatients to a general hospital we conducted a retrospective cohort study of 939 adults consecutively admitted to a free-standing psychiatric hospital in 2010. Transfer to a general hospital was used as a proxy marker for poor medical outcome. The score Age (years) plus BUN (mg/dL) was used in sensitivity analyses to identify patients with medical deterioration in derivation (N = 523) and validation (N = 414) samples. Fifty-two (5.5 %) patients had admission azotemia (BUN >25 mg/dL). Medical deteriorations requiring emergency transfer to a general hospital occurred in 24 (46.2 %; 95 % confidence interval = 32.6–49.8 %) of azotemic patients and 112 (12.6 %; 95 % confidence interval = 10.4–14.8 %) of those with normal BUN (p < 0.0001). Age + BUN ≥90 identified 51 transferred patients and had positive and negative predictive values of 39.8 and 89.5 %, respectively, in the entire sample. We conclude that psychiatric inpatients with BUN >25 mg/dL or Age + BUN ≥90 are at risk for medical deterioration. Free-standing psychiatric hospitals should develop models of care requiring frequent, scheduled medical follow-up and enhanced monitoring for this vulnerable populations.