Introduction: Thyroid function tests (TFT’s) incorporating Thyroid Stimulating Hormone (TSH) and Free Thyroxine (fT4) are some of the most commonly ordered investigations in Geriatric wards. The cost of such clinical practice is currently costing Medicare $203 million per year with an average growth of 6.2% per annum. (1)
Aim: To analyze current practice and determine if TFT’s (TSH and fT4 testing) are related to any trends in clinical efficiency, health outcomes and cost effectiveness for both patients and the health service.
Method: Retrospective study of 329 admissions between 1st January 2018 to 30th June 2018 were studied. 10 variables were analysed and 4 outcomes were measured. Partition modelling was used to identify variables which could significantly affect outcomes and chi square analysis was utilized to determine statistical significance.
Results: Total of 329 admissions met inclusion criteria (mean age 80.2, SD = 9.6, male = 45%, n = 148). 219 had TFT’s tested at some stage during their admission, of which, 0.45% (n = 1) were positive for true hypothyroidism (TSH > 4.5 mU/L and fT4 <7 pmol/L) while 10% (n = 22) resulted in subclinical hypothyroidism (TSH > 4.5 mU/L but fT4 within normal range). Of the positive tests, 42% already had a diagnosis of hypothyroidism, and only 13.6% stimulated a change in management. Overall, only 0.30% of the cohort was deemed to have benefited from TFT screening within the 6-month study period.
Conclusion:
Our recommendation is that TFT’s as a routine screening test in an inpatient setting are not a cost effective measure. Number needed to diagnose was 330 tests, resulting in $11,484 per patient with hypothyroidism. Emphasis should be placed on history and clinical examination, prior to ordering further investigations to confirm or rebuke a clinical diagnosis, as opposed to routine screening.