Is routine measurement of TSH in hospitalized patients necessary?

Abstract

TSH routine testing in hospitalized patients has low efficacy, but may be beneficial in a selected subgroup of patients. Our aim was to evaluate the efficacy of routine thyroid function tests among patients admitted to internal medicine departments. It is a retrospective study. A randomly selected cohort of hospitalized patients with abnormal thyroid-stimulating hormone (TSH) blood tests drawn as part of admission protocol. Patient data were collected from the electronic medical files and analyzed for its efficacy. TSH as a screening test was proven unnecessary in 75% (174) of the study population. Leading causes were non-thyroidal illness syndrome, drugs affecting the test results and subclinical disorders. TSH testing was found to be clinically helpful in only 9 patients; however, all of them had other clinical need for TSH testing. We found a clinically abnormal TSH in 20 patients, hypothyroidism in 11 patients and thyrotoxicosis in 9 patients. Low efficacy ascribed to TSH screening test by this study correlates with recent recommendations that indicate TSH screening in admitted patients only with accompanying clinical suspicion. Most probably, the majority of patients found by screening to have thyrotoxicosis have non-thyroidal illness or drug effects so the threshold for FT4 to diagnose overt thyrotoxicosis should be higher than that in ambulatory patients. In elderly patients, clinically relevant TSH disturbances are more frequent and are harder to diagnose, therefore, TSH screening in this group of patients might be beneficial.

Thyrotoxicosis in patients with COVID-19: the THYRCOV study

“…Noteworthy, the prevalence of hypothyroidism was low in this clinical setting with most of the cases being mild. The cost-effectiveness and diagnostic value of serum TSH measurement in hospitalized patients are controversial (13,14,15). As a matter of fact, an important derangement of hypothalamic-pituitary-thyroid axis takes place during critical illness, configuring the so-called non-thyroidal…”

Things We Do for No Reason™: Routine Thyroid-Stimulating Hormone Testing in the Hospital

“…Mild TSH abnormalities in hospitalized patients do not predict clinically significant thyroid disease. 4,11 The patient in the previously described clinical scenario has NTIS caused by acute on chronic illness and the effect of glucocorticoids. As the hospitalist suspected, the patient's AMS was caused by hypercapnia.…”

“…8 In many hospitals, TSH is included in emergency department laboratory panels and hospital admission order sets (sometimes as a preselected default), which can significantly influence prescriber ordering. 4,6,7,9 Hardwick et al conducted structured interviews with primary care providers to explore the factors contributing to high thyroid testing variability. Among the potential contributing factors identified were fear of a missed diagnosis, as well as the complexity and poor integration of electronic health records, which makes repeat testing easier than requesting outside records.…”

“…In all these cases, patients were either already on a medication known to affect thyroid function (eg, levothyroxine, amiodarone) or the pretest probability of thyroid-related illness was elevated because of clinical presentation. 4 Several institutions have implemented quality improvement (QI) initiatives to reduce inappropriate thyroid function testing without apparent compromise to clinical care. 14 Although none included balancing measures within their QI design, the implementation of simple appropriateness guidelines, for example, has been shown to reduce the frequency of TSH ordering by as much as 50%, which suggests significant overtesting.…”

“…Although most thyroid disease is mild and managed in the outpatient setting, inpatient thyroid testing is common, with evidence suggesting that 21%-100% of internal medicine admissions receive thyroid testing. [4][5][6][7]…”