This study investigates the association between kidney stones and the risk of osteoporotic fracture in patients with chronic kidney disease (CKD). The introduction provides background on how CKD patients have a higher risk of osteoporotic fracture compared to the general population, and how bone mineral density alone has limitations in predicting fracture risk. The authors hypothesize that the occurrence of kidney stones could indicate calcium dysregulation and be a risk factor for poor bone health and fracture in CKD patients.
The methods describe a retrospective study design using medical records from over 2000 patients with stable stage 3-4 CKD treated at a single center in Korea from 2007-2017. Patients with primary hyperparathyroidism, liver disease, cancer, infection, or major trauma were excluded. Of the remaining 2282 patients, 113 had kidney stones. Propensity score matching created groups with 226 patients each, balanced for demographic and clinical factors. Outcomes were osteoporotic fracture incidence and time to first fracture.
The results showed osteoporotic fractures occurred in 29% of CKD patients with kidney stones compared to 14% without, corresponding to rates of 5.6 vs 2.6 per 100 patient years. The fracture risk was 2.5 times higher with kidney stones. In adjusted models, kidney stones remained an independent predictor of fracture, with a hazard ratio of 2.3. There was a synergic effect between kidney stones and more advanced CKD stage on fracture risk.
The authors conclude that kidney stones are significantly associated with osteoporotic fracture risk in CKD patients, even after adjusting for conventional risk factors like age, sex, smoking, and steroid use. This suggests kidney stones could be a clinical indicator of disordered calcium regulation and skeletal effects. The study is limited by the retrospective design, small number of stone formers, lack of data on fracture history, bone density, and stone composition.
Overall, this is an interesting study highlighting a potential connection between kidney stones and fracture risk in CKD patients. The methods are appropriate and the analysis is clear. The results support considering kidney stones as a risk factor for osteoporotic fracture in CKD. Prospective research is needed to confirm the relationship and underlying mechanisms. This study provides insight on an under-recognized factor that may contribute to fracture risk assessment in CKD patients.
Original Article – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6374417/