Calcium supplementation and kidney stone risk in osteoporosis: a systematic literature review.

OBJECTIVES: This paper aims to examine the risk of nephrolithiasis in patients with osteoporosis and calcium supplementation.

METHODS: This work is based on the systematic review of studies retrieved by a sensitive search strategy in Medline and Embase (1991-2010), and the Cochrane Central register of Controlled Trials (CENTRAL) up to 2010. The abstracts of the annual scientific meetings of the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) (2008-2010) were also examined. The selection criteria were the following: patients with osteoporosis, on calcium supplementation alone or associated with other treatments for osteoporosis. We measured the likelihood of developing kidney stones, renal colic, changes in urinary sediment and serum parameters. We selected systematic literature reviews, randomised clinical trials (RCT) and cohort studies.

RESULTS: We included 10 studies, 8 RCT and 2 cohort studies of moderate quality. All patients had osteoporosis (>8.000 patients), they were mostly women with a mean age of 50-70 years. Daily calcium doses varied from 120 mg up to 1.500 mg, and treatment duration from 3 days to 3 years. Changes in urinary sediment were found, but in general they were not clinically relevant. No cases of nephrolitiasis were found in more than a half of the included studies. In total there were 3 cases of kidney stone, 2 urinary tract calcifications, 16 cases of nephrolithiasis or urolithiasis, 4 of haematuria and 5 patients reporting kidney pain.

CONCLUSIONS: According to our results, calcium supplements in the treatment of osteoporosis alone or in combination with another type of treatment does not significantly increase the risk of nephrolithiasis or renal colic.