Published in:
01-10-2012 | Nephrology – Original Paper
Urinary calcium excretion and insulin resistance in patients with acromegaly
Published in: International Urology and Nephrology | Issue 5/2012
Login to get accessAbstract
Background
Renal complications in acromegaly include glomerular hyperfiltration, insulin resistance, hypercalciuria and urolithiasis. The aim of this study was to investigate whether urinary calcium (UCa) excretion is a direct consequence of growth hormone secretion or secondary to hyperfiltration and/or insulin resistance.
Methods
We performed a cross-sectional study of 58 patients diagnosed with acromegaly. Demographic data were obtained, serum analysis was performed, including insulin-like growth factor (IGF)-1, and 24-h urine collection, to measure urinary protein excretion, UCa and phosphate excretion, as well as fractional excretion of sodium and potassium. We also calculated the homeostasis model assessment of insulin resistance (HOMA-IR).
Results
Patients were predominantly male (60.3%), and their mean age was 45.9 ± 14 years. Hypercalciuria was present in 24% of patients. Patients with higher HOMA-IR had higher IGF-1 levels, a trend toward higher body mass index and higher UCa excretion. In univariate analysis, UCa excretion was associated with HOMA-IR (r = 0.472, P = 0.001), phosphaturia (r = 0.457, P = 0.001), IGF-1 (r = 0.398, P = 0.002) and creatinine clearance (r = 0.394, P = 0.001). HOMA-IR and phosphaturia were independently associated with UCa excretion. No independent associations were found between phosphaturia and HOMA-IR or IGF-1.
Conclusions
The present study revealed an association between hypercalciuria and insulin resistance in patients with acromegaly. Further studies are required to fully understand the pathogenesis of these abnormalities in patients with acromegaly.