April - June 2006, Volume 2, Issue 2

Fica SV, Lazar A, Albu A, Barbu C, Grigorescu M

The impact of hyperthyroidism on glycemic control in patients with diabetes mellitus

Acta Endo (Buc) 2006, 2 (2): 203-212
doi: 10.4183/aeb.2006.203

Aim: to evaluate the impact of hyperthyroidism on glycemic control among patients with diabetes mellitus (DM).\r\nResearch design and methods: This retrospective study included patients with hyperthyroidism and DM admitted in Endocrinology, Nutrition Diseases and Diabetes Department of Elias University Emergency Hospital. We evaluated 37 patients (35 women/ 2 men), with a mean age of 54.7?15.3 years and duration of diabetes 8.1?7.49 years; 20 patients with Graves diseases (54%), 10 with toxic multinodular goiter (27%), 5 with autonomous hyperfunctioning adenoma (13%) and 2 with amiodarone induced hyperthyroidism (5.4%). Clinical data were recorded for all our patients, as well as thyroid ultrasound exploration, laboratory analyses (glycosylated hemoglobin, free thyroxine FT4, triiodothyronine T3, thyroid stimulating hormone TSH).\r\nResults: Diabetes control was achieved with: insulin in 23 (62%) patients, antidiabetic oral agents in 9 (24%) and solely diet in 5 patients (13.5%). Hyperthyroid patients had a mean value of glycosylated hemoglobin of 9.3%?2.4% (poor glycemic control) versus 7.2%?1.6% after the treatment of hyperthyroidism. Among insulin-treated patients, the average need of insulin in hyperthyroid status was 0.72 u/kg versus 0.55 u/kg when the patients became euthyroid (p<0.01). We found a significant association between type 1 diabetes mellitus and Graves&#8217; disease compared to toxic multinodular goiter (80% vs 50%, p<0.01).\r\nConclusions: The presence of hyperthyroidism aggravates glycemic control of the patients with diabetes mellitus and increases insulin need in insulin-treated patients. Once the thyroid function was stable, the insulin need decreased significantly (p<0.01). Hyperthyroidism should be radically treated to obtain a good glycemic control. Type 1 diabetes is significantly associated to Graves&#8217;s disease by an autoimmune mechanism.

Keywords: diabetes mellitus, hyperthyroidism, Graves&#8217; disease, glycemic control

Correspondence: Simona Fica, M.D. Department of Endocrinology, &#8220;Carol Davila&#8221; University of Medicine and Pharmacy, Elias Hospital, 17, Marasti Av, Bucharest, Romania, tel: 0040213161614, e-mail:simonafica@yahoo.com