Clinical utility of an ultrasensitive thyroglobulin assay in the follow-up of patients with differentiated thyroid cancer: can the stimulation test be avoided in patients with an intermediate recurrence risk?

SUMMARY: Serum thyroglobulin (Tg) measurement during suppression with levothyroxine (LT4) using an ultrasensitive assay (OnT4-Tg) has been proposed as a replacement of TSH-stimulated Tg measurement (OffT4-Tg) in management of patients with differentiated thyroid cancer (DTC). The aim of this study is to evaluate the capacity of an ultrasensitive Tg assay in predicting an OffT4-Tg > 2.0 ng/mL based on the OnT4-Tg in patients with DTC and an intermediate recurrence risk. We analysed 101 patients with DTC and an intermediate (n = 92) or high risk of recurrence (n = 9) who were treated with total thyroidectomy and ablation with 131I, and followed for an average of 6 years. OnT4-Tg was undetectable in 64 of 101 patients; OffT4-Tg was #x003C; 2.0 ng/mL in 61 of these 64 patients, all with negative imaging results. Furthermore, 37 of 101 patients had detectable OnT4-Tg; 32 of these 37 patients also presented OffT4-Tg > 2.0 ng/mL, and only 3 of these 32 patients had metastases detected by neck ultrasound. Considering a cutoff point of 0.1 ng/mL for OnT4-Tg, the assay had a sensitivity of 91%, specificity of 92%, positive predictive value (PPV) of 86% and the negative predictive value (NPV) of 95% when predicting an OffT4-Tg > 2.0 ng/mL (biochemical disease). The use of an ultrasensitive Tg assay allows prediction of which patients will remain disease-free even if they are at an intermediate risk of recurrence, and to decrease the need for stimulated Tg assays in two-thirds of these patients.

The impact of vitamin D levels on glycemic control and bone mineral density in postmenopausal women with type 2 diabetes.

OBJECTIVES: Whether glycemic control contributes to a decreased number of fractures or favorably impacts bone density in patients with type 2 diabetes mellitus (T2DM)has not been well established. Vitamin D (25 (OH) D3) deficiency appears to be related to glycemic control in patients with T2DM. The aim of this study was to determine the relationship between 25 (OH) D3 levels, glycemic control, bone mineral density (BMD), and the development of osteoporotic fractures (OPF) in postmenopausal women with T2DM. METHODS: We reviewed the charts of 110 postmenopausal women diagnosed with T2DM. Glycosylated hemoglobin A1c (HbA1c) values over the previous 5 years were recorded and an average was obtained. Based on these values,the patients were divided into three groups: optimal,suboptimal, and poor control. Bone mineral density and 25(OH) D3 levels were also recorded. RESULTS: In the group of patients with poorly controlled T2DM, 25 (OH) D3 levels were not significantly lower in comparison with the optimal control group 19.29 ± 7.70 vs 17.26 ± 6.93 (p = 0.53). No statistically significant linear relationship between HbA1c and 25 (OH) D3 levels( r(s) = −0.17, p = 0.06) was established. The frequency of osteoporosis and osteopenia was not significantly different between groups. The group with optimal glycemic control had an increased number of OPF events (p = 0.04). CONCLUSIONS: We do not appreciate a significant relationship between 25 (OH) D3 levels and glucose control or OPF. Therefore, more studies are needed to identify the specific effect of 25 (OH) D3 in T2DM physiopathology.

Evidence of a linkage between neurocardiogenic dysfunction and reactive hypoglycemia.

OBJECTIVE: Reactive hypoglycemia is a common medical problem whose pathophysiology is not completely understood. The objective of this study was to investigate the prevalence of autonomic nervous system abnormalities in patients with reactive hypoglycemia compared with controls. METHODS: Six women, mean age 31 +/- 5 years, with reactive hypoglycemia, and 5 healthy controls women aged 24 +/- 4 years were studied. We investigated the heart rate variability and blood pressure changes after an upright tilt with and without an isoproterenol infusion. A positive result was defined as syncope or presyncope associated with bradycardia, hypotension or both. RESULTS: In response to the orthostatic stress alone or in conjunction with a 4 micrograms isoproterenol infusion, 5 of 6 patients had a positive test as did one of the five control subjects. Patients had a baseline hyperadrenergic tone, with a sympathetic to parasympathetic ratio of 2.3 +/- 0.8 under basal conditions and 10.1 +/- 4.1 during the isoproterenol infusion, compared to 0.7 +/- 0.3 (p = 0.06) and 0.5 +/- 0.1 (p < 0.01) respectively, in the control group. CONCLUSION: Patients with reactive hypoglycemia may be at the extreme end of a spectrum of normal biologic variability, they may have an hyperadrenergic tone and, after a provocative stimulus, sympathetic nerve firing and or synaptic release of NE may not be sufficient to maintain an adequate vascular tone. Alternatively, the vascular response to NE may be impaired. An excessive and paradoxic vasovagal or parasympathetic response was not observed.