Thyroid stimulating hormone testing in ED evaluation of patients with atrial fibrillation and various psychiatric diagnoses.

BACKGROUND: Previous studies of thyroid stimulating hormone (TSH) levels in Emergency Department (ED) patients largely have centered on patients with atrial fibrillation (AF). In our ED patients with AF as well as patients with Psychiatric diagnoses (psych) are screened. The purpose of the present study was to compare TSH levels in the 2 groups. Our hypotheses were that an abnormal TSH and/or AF predicted the need for hospital admission and that TSH is more likely decreased in AF and increased in psych patients. METHODS: Our goal in the study was to compare the use of TSH testing in two ED populations, AF vs. psych patients. The study was a cross sectional cohort of AF vs. psych patients who had TSH levels drawn in the ED over a two year period. Our laboratory ranges were used to determine high vs. low TSH. Two chart examiners collected data after a training process. Charts were reviewed extracting demographic data, TSH levels, outcome (admit vs. discharge), history of AF, thyroid disease, psych diagnoses, presence of CHF, diabetes, hypertension. We compared AF vs. Psych groups using chi square and t-tests for parametric data. Odds ratios were calculated for comparisons between the 2 groups. For non-parametric data Mann Whitney U was used. A logistic regression was performed with the outcome of admission vs. discharge to find predictors of hospital admission. Kappa was calculated for inter-rater agreement. An a priori power analysis showed 80% power with 2 groups of 100 with an absolute difference of 20% between the 2 groups. RESULTS: 252 patients were included, 101 with AF and 152 Psych. Demographics differed in age only with AF patients being older. Mean TSH for AF vs. 2.4 for AF, 2.9 for psych (NS) with no differences in percentages with high or low TSH in the 2 groups. Fifty-three patients had abnormal TSH levels (21%), 27% of AF and 17% of Psych patients (NS). There were significant differences in incidence of CHF, DM, HTN, and tachycardia with more in the AF group (P < 0.001). Significantly more of the psych patients had a history of hypothyroidism (OR 2.28). Our logistic regression showed that taking into account demographics including age, the only predictors of admission were the presence of CHF (aOR 18.6) and having a diagnosis of AF (aOR 4.0). CONCLUSION: There were no differences in TSH levels between the 2 groups. Twenty-one percent had an abnormal level. CHF and AF predicted hospital admission on regression analysis. Many with these AF or Psych diagnoses had abnormal ED TSH levels that could be useful in diagnosis, maintenance, or continuous treatment for their conditions diagnoses.