The oral glucose tolerance test reveals a high frequency of both impaired glucose tolerance and undiagnosed Type 2 diabetes mellitus in primary hyperparathyroidism.

AIMS: To evaluate the frequency of impaired glucose tolerance (IGT)and undiagnosed diabetes mellitus together with the indices of insulin resistance (IR) in primary hyperparathyroidism (pHPT). METHODS: Out of 105 consecutive pHPT patients (F/M 78/27, asymptomatic/symptomatic 68/37, age (mean +/- s.d.) 60.7 +/- 12.7 years,body mass index 25.2 +/- 3.8 kg/m2, ionized calcium (iCa) 1.49 +/- 0.16 mmol/l,parathormone 200.4 +/- 233.9 pg/ml),59 without known diabetes mellitus and controls (n = 60) underwent an oral glucose tolerance test (OGTT, 75 g os). As indices of IR, homeostasis model assessment (HOMAIR)or OGTT data (insulin sensitivity index composite (ISI comp)) were evaluated. RESULTS: In pHPT the prevalence of IGT (mean, 95% confidence intervals (CI), 40.7%, 27.8-53.6) was higher than in controls (25.0%, 13.7-36.3, P < 0.03). Similarly,the prevalence of undiagnosed diabetes mellitus was higher in pHPT(15.3%, 5.8-24.7) than in controls (5.0%, 0-10.7, P < 0.05). Moreover,the prevalence of IGT and undiagnosed diabetes was higher in pHPT than that previously reported in the general population of Northern Italy(8.5% and 3.2%, respectively). The indices showed that insulin resistance was higher in pHPT than in controls: HOMAIR (median, 95% CI,2.6, 2.5-3.9 vs. 1.7, 1.6-2.5, respectively; P < 0.003); ISI comp (3.5, 3.4-4.6 vs. 5.1, 4.9-7.2, respectively; P < 0.002). CONCLUSIONS: Our data in a large and modern day pHPT series, with a preponderance of asymptomatic patients, confirm increased insulin resistance and pre-valence of IGT and undiagnosed diabetes.

Left ventricular hypertrophy in primary hyperparathyroidism. Effects of successful parathyroidectomy.

OBJECTIVE: The association between primary hyperparathyroidism (PHPT) and increased mortality mainly from cardiovascular disease is still debated. The increased mortality previously reported in PHPT was not confirmed in a recent population based study. A high prevalence of left ventricular (LV) hypertrophy was, however, reported in this disease. Although arterial hypertension is regarded as the principal factor, the pathogenesis of LV hypertrophy in PHPT is complex and not completely defined, moreover the effects of successful parathyroidectomy (PTX) are not fully elucidated. The aims of this study were: to ascertain the prevalence of LV hypertrophy in a series of patients with PHPT in comparison to a control population, to seek for relationship between biochemical markers of disease, blood pressure (BP) levels and LV measurements and to evaluate the effects of successful PTX on LV hypertrophy during short-term follow-up. SUBJECTS AND DESIGN: Forty-three patients affected by active PHPT (16 males and 27 females, mean age 60.2 +/- 12.7 years) and 43 controls age- and sex-matched with the same prevalence of arterial hypertension were studied in a case-control analysis. Each subject underwent a M- and 2D mode echocardiographic evaluation and repeated BP measurement. In 21 PHPT submitted to surgery the echocardiographic measurement was repeated 6 months after successful PTX. MEASUREMENTS: Serum concentrations of parathyroid hormone (PTH), total-(Ca) and ionized calcium (iCa), phosphate, creatinine, total alkaline phosphatase (TALP) were measured in patients with PHPT at diagnosis and six months after PTX in the subgroup operated on; BP values were measured in three different occasion; mono and 2D echocardiographic evaluation was performed in control subjects and patients with PHPT either before and after PTX. RESULTS: LV hypertrophy, measured by LV mass index (LVMI), was present in 28/43 PHPT patients (65.1%) and in 15/43 (34.8%) controls, P < 0.05; among hypertensive subjects, 21/21 (100%) PHPT patients and 13/21 (61.9%) controls P < 0.05 were hypertrophic while among normotensive subjects, these figures were 7/22 (31.8%) for PHPT patients and 2/22 (9%) for controls, P = 0.67. At multiple regression analysis in a model including biochemical parameters and BP values, serum PTH levels were associated with LVMI values as the strongest predicting variable (0.46, P < 0.02). Six months after PTX, LVMI decreased (137.8 +/- 37.3 vs 113.0 +/- 28.5, P < 0.05) without changes in mean BP values and ratio of hypertensive patients. CONCLUSION: The present data confirm the high prevalence of LV hypertrophy in primary hyperparathyroidism also in a group of patients with an asymptomatic clinical presentation. The correlation between PTH values and left ventricular mass index suggests an action of the hormone in the pathogenesis of LV hypertrophy confirmed also by the decrease of left ventricular mass index after the reduction of PTH levels. The reversal of left ventricular mass index after parathyroidectomy could affect mortality in primary hyperparathyroidism. An echocardiographic study could be suggested in the clinical work-up of primary hyperparathyroidism in order to evaluate heart involvement and the response to successful parathyroidectomy.