Clinical implications of subclinical hypothyroidism in continuous ambulatory peritoneal dialysis patients

Despite the high prevalence of subclinical hypothyroidism in patients with chronic kidney disease, little is known about the clinical features and implications of this disorder in end-stage renal disease patients. This study aimed to investigate the clinical implications of subclinical hypothyroidism in continuous ambulatory peritoneal dialysis (CAPD) patients.

This is a cross-sectional study with 51 stable patients who were maintained on CAPD for more than 3 months. A thyroid function test with blood sampling and echocardiography were conducted. Subclinical hypothyroidism was defined as a thyrotropin (TSH) level over 5 mIU/l and normal free T(4).

Of the 51 patients, subclinical hypothyroidism was detected in 14 (27.5%). Among those with subclinical hypothyroidism, only 4 (28.6%) patients had autoimmune thyroiditis. Patients with subclinical hypothyroidism had lower left ventricular ejection fractions (LVEF; 61.5 vs. 70.0%, p = 0.002) and lower fractional shortening at endocardial levels (endoFS; 33.9 vs. 40.0%, p = 0.009) compared to those with normal TSH levels. In addition, logTSH was inversely associated with LVEF (r = -0.361, p = 0.009) and endoFS (r = -0.320, p = 0.022). In a multivariate linear regression, adjusted for age, diabetes, previous coronary artery disease and logCRP (C-reactive protein), logTSH was an independent correlate with LVEF (beta = -0.388, p < 0.001).

This study suggests that subclinical hypothyroidism is common and might be implicated in cardiac dysfunction in CAPD patients.