A trial of thyroxine in acute renal failure

Background. Acute renal failure (ARF) remains a serious medical problem wit h a high mortality rate. Efforts to shorten the course of ARF might reduce this mortality. Since thyroxine has been shown in experimental models to sh orten the course of ARF, we designed a trial to determine if a defined cour se of thyroxine would alter the course or change the mortality of clinical ARF. Methods. A prospective, randomized, placebo-controlled, double-blind trial of thyroxine was carried out in patients with ARF. End points were the perc entage requiring dialysis, the percentage recovering renal function, time t o recovery, and mortality. Results. Fifty-nine patients were randomized to receive either thyroxine or placebo. The groups were well matched in terms of basal and entry creatini nes, age, sex, APACHE II scores at entry, and percentage oliguric. Baseline thyroid functions, including T-3, T-4, rT(3), and thyroid stimulating horm one (TSH) levels, were equal between the two groups and typical of patients with euthyroid sick syndrome. Thyroxine resulted in a progressive and sust ained suppression of TSH levels in the treated group, but had no effect on any measure of ARF severity. Mortality was higher in the thyroxine group th an the control group (43 vs. 13%) and correlated with suppression of TSH. Conclusions. In contrast to the beneficial effects seen in experimental ARF , thyroxine has no effect on the course of clinical ARF and could have a ne gative effect on outcome through prolonged suppression of TSH. Critically i ll euthyroid sick patients should not be replaced with thyroid hormone.