SUB-CLINICAL THYROID DYSFUNCTION DOES NOT AFFECT SIX MONTH MORTALITY IN ELDERLY PATIENTS AFTER HIP FRACTURE: A PROSPECTIVE LONGITUDINAL STUDY

Abstract

Mortality after hip fractures in the elderly is one of the most important patient outcome measures. Sub-clinical thyroid dysfunction is common in the elderly population. This is a prospective study of 131 elderly patients with a mean (SD) age of 82.0 (8.9) years (range: 61–94) admitted consecutively to our trauma unit. The aim of the study was to determine the prevalence of sub-clinical thyroid dysfunction in an elderly cohort of patients with hip fracture and to determine if this affects the one year mortality.

There were three times more women (n=100) than men (n=31) in this cohort. All patients underwent surgical treatment for the hip fracture. The prevalence of sub-clinical hypothyroidism (TSH > 5.5 mU/L) was15% (n=20) and of sub-clinical hyperthyroidism (TSH < 0.35 mU/L) was 3% (n=4). Overall 18% (n=24) of patients had a subclinical thyroid dysfunction. The twelve month mortality was 27% (n=36).

Age, gender, heart rate at admission, pre-existing Coronary Heart Disease, ASA grade and presence of overt or subclinical thyroid dysfunction were analysed for association with twelve month mortality using a forward stepwise logistic regression analysis. Only ASA grade was found to significantly affect mortality at twelve months (c2 = 3.98, df = 1, p =.046). The presence of sub-clinical hypo or hyper – thyroidism was not associated with a higher mortality (p = 0.278).

We conclude that sub-clinical thyroid dysfunction does not affect the one year mortality in elderly patients treated surgically for hip fracture.