No Increased Fracture Rate with Decreasing eGFR
ST. JOHN'S, NEWFOUNDLAND—A new analysis suggests there is no association between lower estimated glomerular filtration rate (eGFR) and non-traumatic hip-, vertebral- or wrist-fracture rates. This contradicts earlier studies showing a four-fold higher fracture rate with end-stage renal disease (ESRD).
A team from the Foothills Medical Centre, Calgary, Alberta, analyzed data from the Alberta Kidney Disease Network and the Alberta health and Wellness database. They found that, among 1,815,943 adults without pre-existing ESRD or an eGFR below 15 ml/min/1.73 m2, fracture rates were similar at all eGFR levels.
“Although I think these results are intriguing—they're quite different from the other existing observational studies and different than what you might think—they are not definitive and require prospective confirmation,” noted Meghan Elliott, MD, a nephrology trainee who led the study and presented the results at the Canadian Society of Nephrology's 2012 annual meeting.
A study known as FRACTURE (Fracture Risk Assessment in Chronic kidney disease, prospective Testing Under Real world Environments) was launched in 2010 to rigorously study this relationship. The investigators are following more than 200 patients with stages 3-5 chronic kidney disease to assess development of, and risk factors for, bone disease and fractures (BMC Nephrol 2010;11:17).
The Calgary database analysis was based on comparing eGFRs of 15-29, 30-44, 45-59, and 60 and over, in patients aged 18-64, 65-74, 75-84, and 85 years and older. Moreover, the team analyzed not only hip and vertebral fractures, which are commonly included in such studies, but also wrist fractures “because they have been used as a measure of fragility, or non-traumatic, fractures in the general population,” Dr. Elliott said.
The researchers' examination of the baseline characteristics indicated that, as expected, individuals with lower eGFRs had higher median ages and were more likely to have diabetes, hypertension or heart failure, or to have had a heart attack, than those with higher eGFRs.
After adjusting for confounding factors, the team found no significant changes in rates of non-traumatic hip, vertebral, or wrist fracture with decreasing eGFRs in either men or women within each age group. The researchers observed significant changes between age groups, however.
The investigators also compared patients with an eGFR above 60 and those with lower eGFR levels. They found no increase in the rates of hip, wrist or vertebral fractures.