Aortic calcification and lower bone mineral density (BMD) are significantly more common among recurrent kidney stone formers (KSFs) than among non-stone formers, researchers found.
The finding suggests that vascular calcification (VC) “may be an underlying mechanism explaining reported associations between nephrolithiasis and cardiovascular disease,” according to a report published online ahead of print in the Clinical Journal of the American Society of Nephrology.
Linda Shavit, MD, of the Adult Nephrology Unit, Shaare Zedek Medical Center in Jerusalem, Israel, and colleagues conducted a retrospective study that included 57 KSFs and 54 healthy age- and gender-matched controls selected from a list of potential living kidney donors. Both groups had a mean age of 47 years. The researchers used computed tomography (CT) to assess abdominal aortic calcification (AAC) and vertebral bone mineral density (BMD). AAC is considered a strong predictor of cardiovascular (CV)-related morbidity or death, the researchers explained.
The prevalence of AAC was similar in the KSFs and controls (38% and 35%, respectively), but AAC severity score was significantly higher in the KSFs than controls and average CT BMD was significantly lower in KSFs (159 vs. 194 Hounsfield units).
In multivariate analysis, KSFs had higher AAC scores and lower CT BMD compared with non-stone forms, according to the investigators. The association between AAC score and hypercalciuria among stone formers was not statistically significant.
“Although our study cannot prove causality,” the authors wrote, “this is the first study to our knowledge to provide controlled evidence for a possible role of vessel calcification and associated osteoporosis in CV morbidity among KSFs. Our findings may serve as a useful basis for future prospective trials exploring the potential benefit of therapeutically targeting the bones and cardiovascular system in KSFs as part of their routine management to mitigate CVD morbidity and mortality.”
The researchers acknowledged some study limitations, including the retrospective collection of demographic and clinical variables. “Therefore, we cannot exclude known or unknown confounding factors entirely as an explanation for our results.” In addition, the control group consisted of potential living kidney donors, who may be “healthier” than the general population, they noted.