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Risk factors for nephrolithiasis in patients with familial idiopathic hypercalciuria
Nicolas Lerolle1, Brigitte Lantz, Françoise Paillard
1Service de Néphrologie A, Hôpital Tenon, Paris, France.
Insights
Idiopathic hypercalciuria significantly increases kidney stone risk. Higher urine calcium and uric acid levels, along with age, are key risk factors for stone formation in affected families.
Area of Science:
- Nephrology
- Urology
- Genetics
Background:
- Idiopathic hypercalciuria affects approximately 40% of nephrolithiasis patients.
- Familial predisposition to kidney stones is common, but risk factors within these families are not well understood.
Purpose of the Study:
- To investigate the frequency and risk factors for kidney stone formation in hypercalciuric patients within families.
- To identify independent predictors of nephrolithiasis in subjects with familial idiopathic hypercalciuria.
Main Methods:
- Prospective study of 216 subjects from 33 families with idiopathic hypercalciuria.
- Collected data on demographics, medical history, and 24-hour urine composition.
- Utilized multivariate logistic regression to determine independent risk factors for stone formation.
Main Results:
- Nephrolithiasis prevalence was significantly higher in hypercalciuric subjects (46%) compared to normocalciuric subjects (11%).
- Independent risk factors for nephrolithiasis included older age, increased urine calcium excretion, and elevated uric acid excretion.
- A progressive increase in stone risk was observed with higher levels of hypercalciuria.
Conclusions:
- A significant dose-effect relationship exists between calciuria and kidney stone disease in familial hypercalciuria.
- Elevated uric acid excretion and age are associated with increased stone formation risk, likely due to dietary factors and cumulative exposure.
- These findings highlight the importance of monitoring urinary calcium and uric acid levels in individuals with a family history of kidney stones.
Purpose:
About 40% of patients with nephrolithiasis have idiopathic hypercalciuria, sometimes associated with a family history of kidney stones. In these families, little is known about the frequency of, and risk factors for, stone formation among hypercalciuric patients. We therefore conducted a prospective study of 216 subjects from 33 families with idiopathic hypercalciuria.
Materials And Methods:
We recorded the age, weight, and history of calcium stones in all subjects, and measured 24-hour urine volume and excretion of calcium, uric acid, sodium, magnesium, urea, citrate, phosphate, and sulfate on a nonrestricted diet. We performed a more complete metabolic evaluation in many of the hypercalciuric subjects (calciuria/weight >0.1 mmol/kg/d). Multivariate logistic regression analysis was performed to identify independent risk factors for stone formation.
Results:
The prevalence of self-reported nephrolithiasis was 46% (61/132) in hypercalciuric subjects and 11% (7/63) in normocalciuric subjects (P <0.0001). In multivariate analysis, age (odds ratio [OR] per 10 years of age = 1.3; 95% confidence interval [CI]: 1.1 to 1.6), urine calcium excretion (OR = 1.3 per mmol/d increase; 95% CI: 1.2 to 1.5), and uric acid excretion (OR = 3.3 per mmol/d increase; 95% CI: 1.4 to 7.5) were independent risk factors for nephrolithiasis. The risk of nephrolithiasis increased progressively with greater levels of hypercalciuria.
Conclusion:
We found a significant dose-effect association between calciuria and stone disease in patients with familial hypercalciuria. Other factors associated with stone formation included higher uric acid excretion, probably reflecting higher food intake, and age, probably reflecting the length of exposure to hypercalciuria and hyperuricosuria.