title: Elevated blood urea nitrogen and medical outcome of psychiatric inpatients.
abstract: 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.
authors.affiliation: Zucker Hillside Hospital, North Shore - Long Island Jewish Health System, 75-59 263rd Street, Glen Oaks, NY, 11004, USA, pmanu@nshs.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Manu
authors.forename: Zainab
authors.initials: Z
authors.lastname: Al-Dhaher
authors.forename: Sameer
authors.initials: S
authors.lastname: Khan
authors.forename: John M
authors.initials: JM
authors.lastname: Kane
authors.forename: Christoph U
authors.initials: CU
authors.lastname: Correll
mesh_terms: D000367:Age Factors; D000368:Aged; D053099:Azotemia / Q000097:blood* / Q000453:epidemiology; D001806:Blood Urea Nitrogen; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D006801:Humans; D007297:Inpatients; D008297:Male; D001523:Mental Disorders / Q000097:blood* / Q000453:epidemiology; D008875:Middle Aged; D063868:Patient Outcome Assessment; D010360:Patient Transfer / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D012189:Retrospective Studies