Iodine retention and thyroid dysfunction in patients on hemodialysis and continuous ambulatory peritoneal dialysis

Povidone-iodine is frequently used as an antiseptic in patients on chronic dialysis. In order to determine if the use of povidone-iodine affects thyroid function in these patients, we measured serum iodine and thyroid hormone levels in dialysis patients prior to and following discontinuation of topical povidone-iodine antiseptics. Serum inorganic iodine levels were elevated initially in nearly 90% of the patients (19 on hemodialysis, 12 on continuous ambulatory peritoneal dialysis [CAPD]). Following discontinuation of povidone-iodine, iodine levels over a 3-month period decreased modestly in patients on CAPD (n = 5) and were unchanged in patients on hemodialysis (n = 5). Total and free thyroxine levels were frequently low but did not correlate with protein-bound or inorganic iodine levels and did not change after discontinuation of povidone-iodine. Thyrotropin levels correlated significantly (r = .62, P less than .01) with inorganic iodine levels in patients on hemodialysis, but not for patients on CAPD. We conclude that abnormal thyroid function tests are common in dialysis patients but are not related to iodine retention or to the routine use of topical povidone-iodine-containing antiseptics.