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Insulin resistance is not coupled with defective insulin secretion in primary hyperparathyroidism
Author(s) -
Tassone F.,
Procopio M.,
Gianotti L.,
Visconti G.,
Pia A.,
Terzolo M.,
Borretta G.
Publication year - 2009
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2009.02804.x
Subject(s) - medicine , primary hyperparathyroidism , quantitative insulin sensitivity check index , endocrinology , insulin resistance , insulin , body mass index , blood pressure , diabetes mellitus , hyperparathyroidism , insulin sensitivity
Aims An increased frequency of both impaired glucose tolerance and Type 2 diabetes mellitus (DM) has been reported in primary hyperparathyroidism (pHPT), thus we sought to investigate insulin sensitivity and insulin secretion in a large series of pHPT patients. Subjects and methods One hundred and twenty‐two consecutive pHPT patients without known DM were investigated [age (mean ± sd ) 59.3 ± 13.6 years, body mass index (BMI) 25.7 ± 4.2 kg/m 2 ; serum calcium 2.8 ± 0.25 mmol/l; PTH 203.2 ± 145.4 ng/l]. Sixty‐one control subjects were matched, according to the degree of glucose tolerance, in a 2 : 1 patient:control ratio. Fasting‐ and oral glucose tolerance test‐derived estimates of insulin sensitivity and secretion were determined by means of the quantitative insulin sensitivity check index (QUICKI) and the insulin sensitivity index (ISI) composite. Results Both the QUICKI and ISI composite were lower in pHPT patients than control subjects ( P < 0.03 and P < 0.05, respectively) after adjusting for age, systolic blood pressure and BMI. Conversely, all insulin secretion estimates were significantly increased in pHPT patients than in control subjects ( P < 0.04 and P < 0.03, respectively) and after adjusting for age, systolic blood pressure and BMI. Log serum calcium levels were negatively associated with the QUICKI and log ISI composite ( R = −0.30, P = 0.001; R = −0.23, P = 0.020, respectively) in pHPT patients. Serum calcium levels significantly and independently contributed to impaired insulin sensitivity in multivariate analysis (QUICKI as dependent variable: β = −0.31, P = 0.004, R 2 = 0.15; log ISI composite as dependent variable: β = −0.29, P = 0.005, R 2 = 0.16). Conclusions Our study confirms a reduction in both basal and stimulated insulin sensitivity in primary hyperparathyroidism, in spite of increased insulin secretion. Moreover, our data show for the first time a significant relationship between hypercalcaemia and insulin sensitivity in this condition.