T3 Syndrome Associated with Risk for Cardiovascular Complications

Clinical Journal of the American Society of Nephrology. 2015.10(6):975-982.

It has been reported that there is a direct association between low triidothyronine (T3) syndrome and cardiovascular mortality in patients receiving hemodialysis. However, according to Tae Ik Chang, MD, and colleagues, there are few data on low T3 syndrome in patients on peritoneal dialysis. The researchers conducted a prospective, observational study designed to assess the association between low T3 syndrome and cardiovascular mortality, including sudden death, in a large cohort of incident peritoneal dialysis patients.

The study included 447 euthyroid patients who initiated peritoneal dialysis between January 2000 and December 2009. At baseline, measurement of thyroid hormones was performed. During a median of 46 months of follow-up, both all-cause and cause-specific deaths were recorded. Based on tertile of T3 levels, the researchers compared the survival rate among the three groups.

In Kaplan-Meyer analysis, patients with the lowest tertile of T3 levels were significantly associated with higher risk of all-cause and cardiovascular mortality, including sudden death (P<.01 for trend). In Cox analyses, following adjustment for well-known risk factors (inflammation and malnutrition), T3 level was a significant predictor of all-cause mortality (per 10-unit increase, adjusted hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.78-0.94; P=.002), cardiovascular death (per 10-unit increase, adjusted HR, 0.84; 95% CI, 0.75-0.98; P=.01), and sudden death (per 10-unit increase, adjusted HR, 0.69; 95% CI, 0.56-0.86; P=.001).

There was also an independent association between higher T3 level and lower risk of sudden risk (per 10-unit increase, adjusted HR, 0.71; 95% CI, 0.56-0.90; P=.01). This association remained significant even after accounting for competing risks of death from other causes.

“T3 level at the initiation of [peritoneal dialysis] was a strong independent predictor of long-term [cardiovascular] mortality, particularly sudden death, even after adjusting for well-known risk factors. Low T3 syndrome might represent a factor directly implicated in cardiac complications in [peritoneal dialysis] patients,” the researchers concluded.