Temperature in the Hospitalized Patient

BACKGROUND:  Human body temperature and its variations are believed to be linked to clinical diagnoses. However, most of the available data stems from healthy individuals, with no large-scale studies addressing body temperature among inpatients. The focus of our report is to determine the role of measurement site, age, and gender on body temperature among hospitalized patients. METHODS: This is a retrospective analysis of a total of 695,107 temperature readings from 16,245 patients hospitalized over 1-year period at a tertiary medical center, ages 0 to 105 years, 50% female, with measurements sites: rectal, monotherm, axillary, oral, temporal, and tympanic. The average temperature (Tave) per patient and per site of measurement was used in all calculations. The data was analyzed with EXCEL and MATLAB. Descriptive statistics, Student's T-test, and Pearson's correlation were used, where appropriate, with statistical significance set at p<0.05. FINDINGS: Tave from all measurement sites was 98.13 /-0.48 (SD) F (36.74 /-0.27 C) with positively skewed normal distribution. Tave varied by site of measurement, in decreasing order highest-to-lowest being rectal, monotherm, axillary, oral, temporal, and tympanic, all of which were higher than the available reported averages for healthy subjects. Tave from most measurement sites decreased as patients' age increased. On average and when including all per-person Tave readings from all measurement sites, women had a slightly lower body temperature (98.19 /-0.47 F (36.77 /-0.26 C)) compared to men (98.22 /-0.49 F (36.79 /-0.27 C)) which reached statistical but likely no physiological significance. Subgroup analysis demonstrated that the gender-based difference is highest among younger adults, with similar results available from outpatient studies. Finally, we found differences in Tave between the ICUs, listed from highest-to-lowest: Neuro ICU, Pediatric ICU, Surgical ICU, Cardiac ICU, Medical ICU. However, there was no difference between all ICUs and non-ICU patients. CONCLUSIONS: Our data demonstrates the various trends of average body temperatures in a hospitalized patient. It quantifies variability in body temperature, based on gender, age, location of the patient, and method of measurement.  It confirms trends previously identified among healthy subjects are preserved in the inpatient setting. To our knowledge, ours is the first study that evaluates the temperatures of all hospitalized patients at a large tertiary medical center. Funding: None Declaration of Interest: None of the authors of this manuscript have a conflict of interest related to this manuscript. Ethical Approval: Institutional Review Board (IRB) approval for exemption was obtained prior to initiating the study. All data was collected retrospectively.