Nutrition and urinary calcium stone formation in northwestern India: a case control study

Protocol-based metabolic evaluation in high-risk patients with renal stones in North India

CONTEXT

Renal calculus disease has a lifetime recurrence rate of 80%. Protocol-based metabolic evaluation in high-risk subjects for recurrent renal stones reveals abnormalities in a large subset of subjects. However, such information is not available in Indian subjects.

AIMS

To evaluate the abnormalities by a protocol-based metabolic evaluation in patients at a high risk for recurrent renal stones.

SETTINGS AND DESIGN

Prospective, academic tertiary care center.

MATERIALS AND METHODS

Fifty North Indian patients (38 males and 12 females; mean age 38 ± 10.2 years) with recurrent or bilateral renal stones were evaluated. All subjects underwent a protocol-based evaluation involving estimation of serum total calcium, phosphorus, creatinine, albumin, iPTH, 25(OH)D(3), 1,25(OH)(2)D(3), and a calcium load test. Estimation of daily urinary excretion of volume, oxalate, calcium, uric acid, and citrate, and urinary acidification studies were performed.

STATISTICAL ANALYSIS USED

Descriptive statistics and t-test.

RESULTS

An underlying disorder was detected in 48 (96%) patients. Almost half had two or more metabolic abnormalities. The metabolic abnormalities detected were: Hypercalciuria 26 (52%) patients, renal hypercalciuria 16 (32%), absorptive hypercalciuria 6 (12%), unclassified hypercalciuria 4 (8%), hyperoxaluria 27 (54%), hyperuricosuria 9 (18%), distal renal tubular acidosis 4 (8%; 2 complete and 2 partial), primary hyperparathyroidism 3 (6%), and hypocitraturia 14 (n=18, 77%). In two patients, the etiology could not be detected.

CONCLUSIONS

Protocol-based metabolic evaluation reveals metabolic abnormalities in majority of patients with nephrolithiasis. The spectrums of metabolic abnormalities are different in Indian subjects as compared to the western population.

Haematuria and urolithiasis in patients with haemophilia

Recurrent haematuria was present in 18 of 474 moderate and severe haemophiliacs, the cause of which was found to be urolithiasis in six patients (33%). The prevalence of urolithiasis in haemophiliacs was found to be significantly higher than that reported from the general population, i.e. 4.5 of 10 000 population under 40 yr of age (odds ratio (OR) 23.4; 95% CI 18.2-28.7; lambda2 test P < 0.01). Even when this prevalence was corrected for gender bias, i.e. male : female (5 : 1), the significance of the present findings remain (OR 17.6; 95% CI 13.8-21.5; lambda2 test P < 0.01). In developing countries, severe and moderately severe haemophiliacs may be at a higher risk of urolithiasis because of prolonged recumbency necessitated by recurrent joint bleeds and inadequate replacement therapy.