Elevated free thyroxine and free triiodothyronine probably caused by high-dose biotin intake in a patient with Graves' disease: a case report.

Biotin is a water-soluble vitamin that acts as a cofactor for carboxylase, and is often used as a component in several immunoassays. We present a case of a 46-year-old male with Graves' disease (GD) who revealed elevated free thyroxine (FT4) and free triiodothyronine (FT3) levels after high-dose biotin intake. Levels of these hormones had been within the reference range when he was on thiamazole 5 mg/day for 7 years; however, the levels increased from 1.04 to 2.20 ng/dL and from 3.05 to 9.84 pg/mL for FT4 and FT3, respectively, after he started taking biotin 72 mg/day. Despite these high levels, his symptoms and the other laboratory results, including the thyroid-stimulating hormone level, did not suggest GD relapse. His thyroid hormone data was decreased and returned within the reference range immediately after the laboratory assays for FT3 and FT4 had been coincidentally changed from those containing streptavidin-biotin complexes to biotin-free ones. Biotin interference, which is caused by high-dose biotin intake and immunoassays using some form of streptavidin-biotin complex, is sometimes clinically problematic, giving high or low results. To our knowledge, this is the first case report of a patient with GD on high-dose biotin receiving high thyroid hormone level results that were initially misunderstood as an aggravation of the disease; there are some reports of misdiagnosis of hyperthyroidism due to biotin administration. Unexpected fluctuations in thyroid function test results in patients with GD should be checked for biotin intake, immunoassays and the limiting concentration of biotin to avoid misdiagnosis of relapse.

Comprehensive efficacy of ipragliflozin on various conditioned type 2 diabetes compared with dipeptidyl peptidase-4 inhibitors and with both agents, based on a real-world multicenter trial.

AIMS: The effects of ipragliflozin, the first sodium-glucose co-transporter 2 inhibitors (SGLT2i) launched in Japan in 2014, and with dipeptidyl peptidase-4 inhibitors (DPP-4i) on glycemic control and metabolic changes were investigated comprehensively on various conditioned type 2 diabetes (T2DM) by evaluating various clinical parameters in a real-world setting. MATERIALS AND METHODS: A total of 101 patients with T2DM aged 20-80 years with 7.0% ≤ HbA1c < 10.0% were followed in this 52-week, open-label, prospective, real-world, multicenter study. RESULTS: HbA1c decreased significantly in all groups. In ipragliflozin using groups, body weight, waist circumference, blood pressure, HOMA-IR, AST, ALT, γ-GTP, uric acid and leptin levels decreased, in contrast, HDL-cholesterol, total ketone bodies, blood urea nitrogen, creatinine, RBC, hemoglobin and hematocrit levels increased, however, in DPP-4i sole group, no significant trends were observed in these parameters. Change in leptin positively correlated with insulin, while change in total ketone bodies inversely correlated with ALT in ipragliflozin using groups. Fasting active gastric inhibitory polypeptide levels decreased in ipragliflozin sole group. Glucagon showed no changes. No significant safety concerns were observed in this study. CONCLUSIONS: Ipragliflozin is useful and safe, showing some contrastive effects on several clinical parameters which are not shown with DPP-4i, resulting several clinical benefits. The co-administration of ipragliflozin and a DPP-4i has a better clinical outcome than either single-agent therapy.