Elevated blood urea nitrogen and medical outcome of psychiatric inpatients

Peter Manu, Zainab Al-Dhaher, Sameer Khan, John M. Kane, Christoph U. Correll

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)111-120
Number of pages10
JournalPsychiatric Quarterly
Issue number1
StatePublished - Mar 2014
Externally publishedYes


  • Age
  • Blood urea nitrogen
  • Medical outcome
  • Predictive value
  • Psychiatric inpatients

ASJC Scopus subject areas

  • Psychiatry and Mental health


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