Bones of contention: Predicting and preventing fractures in patients receiving peritoneal dialysis

Low bone density is common among those individuals receiving peritoneal dialysis. While cross-sectional studies support an association between low bone mineral density (BMD) and prevalent fracture, relying on bone density alone, particularly at the lumbar spine and in those with high degrees of hyperparathyroidism may underestimate fracture risk. Commonly used risk calculators in the general population have been shown to perform reasonably well in those receiving dialysis although they do not include any risk factors for high turnover bone disease that may play a role in increased fracture risk. The best options for decreasing fracture risk in patients receiving peritoneal dialysis are unclear. The evidence for bisphosphonates is limited to small studies of BMD, and concerns about drug accumulation have limited their use. Denosumab is more commonly used and has some evidence for improvement in BMD but carries with it a high risk of hypocalcaemia requiring rigorous prophylaxis. More research is needed to explore practical methods to identify those at risk of fracture and determine the efficacy of antiresorptive and anabolic therapies to decrease this risk.

Magnesium and Fracture Risk in the General Population and Patients Receiving Dialysis: A Narrative Review

Purpose of Review

Magnesium is an essential mineral for bone metabolism, but little is known about how magnesium intake alters fracture risk. We conducted a narrative review to better understand how magnesium intake, through supplementation, diet, or altering the concentration of dialysate magnesium, affects mineral bone disease and the risk of fracture in individuals across the spectrum of kidney disease.

Sources of Information

Peer-reviewed clinical trials and observational studies.

Methods

We searched for relevant articles in MEDLINE and EMBASE databases. The methodologic quality of clinical trials was assessed using a modified version of the Downs and Black criteria checklist.

Key Findings

The role of magnesium intake in fracture prevention is unclear in both the general population and in patients receiving maintenance dialysis. In those with normal kidney function, 2 meta-analyses showed higher bone mineral density in those with higher dietary magnesium, whereas 1 systematic review showed no effect on fracture risk. In patients receiving maintenance hemodialysis or peritoneal dialysis, a higher concentration of dialysate magnesium is associated with a lower concentration of parathyroid hormone, but little is known about other bone-related outcomes. In 2 observational studies of patients receiving hemodialysis, a higher concentration of serum magnesium was associated with a lower risk of hip fracture.

Limitations

This narrative review included only articles written in English. Observed effects of magnesium intake in the general population may not be applicable to those with chronic kidney disease particularly in those receiving dialysis.