Thyroid evaluation of hospitalized psychiatric patients: the role of TSH screening for thyroid dysfunction.

The incidence and pattern of changes in thyroid function tests were studied in acutely hospitalized psychiatric patients and the cost effectiveness of a systematic screening program for thyroid dysfunction was estimated. Thyroid testing was performed on 1275 of 1424 (90%) admissions to the psychiatric wing of Strong Memorial Hospital between April 1, 1993 and March 30, 1994. Discharge samples were obtained in 232 patients who were hospitalized at least 2 days; 163 patients were admitted multiple times. Psychiatric diagnosis was coded using DSM-III-R criteria. TSH, T4, free T4, and T3 levels were measured within 48 h of admission. TSH values were most frequently abnormal (7.8%) and free T4 the least (1.3%). Admission and discharge thyroid tests were similar. Significant differences in the four parameters of thyroid function were present among the psychiatric groups. By analysis of variance every 1 microU/mL increase in TSH levels was associated with a 2.5% increase in length of stay (LOS) (95% confidence intervals: 0.21%, 4.75%), holding psychiatric diagnosis, age, and gender constant. For patients with elevated TSH levels, the average LOS was increased by 10.7 days (95% confidence intervals: 2.8, 18.7 days). It is concluded that patients hospitalized for psychiatric illness have an incidence of thyroid dysfunction at or slightly higher than the general population. However, patients with elevated TSH levels are hospitalized longer than those with normal or suppressed values.