CKD Severity Linked to Low BMD, Hip Fracture, and Mortality
The risk of dying following a hip fracture was 6.5 times higher for patients with severe CKD than for those with normal kidney function or mild CKD.
SAN DIEGO—Bone mineral density (BMD) can predict hip fracture in chronic kidney disease (CKD) patients, according to research findings presented at Kidney Week. Furthermore, end-stage renal disease (ESRD) patients who experience hip fracture have higher risks of early death compared with patients with normal kidney function or mild CKD.
Farsad Afshinnia, MD, of the University of Michigan in Ann Arbor, and his team examined bone densitometry results, clinical data, and laboratory values for 25,109 mostly Caucasian CKD patients (average age 61 years; 80% female) from the university's health system. More than 20,000 patients had stage 1 or 2 CKD; 4,223 had stage 3; 293, stage 4; and 83, stage 5. Deficient bone mineralization was defined as 2.5 or less standard deviations below the average peak bone mass of young healthy adults.
A higher proportion of stage 5 CKD patients (27.7%) had deficient mineralization in the hip than stage 1 or 2 patients (6.4%). Hip fracture also occurred in more stage 5 than stage 1 or 2 patients (9.6% vs. 1.9%). Having severe CKD (stage 4 or 5) was associated with more than twice the odds of deficient mineralization in the hip and more than 1.5 times the odds of hip fracture, compared with the earliest stages of CKD.
Of 544 patients with hip fracture, 22.4% died. When researchers adjusted for age and co-existing illnesses, they determined the risk of mortality after hip fracture was 6.5 times higher in stage 5 CKD patients (estimated glomerular filtration rate below 15 mL/min/1.73m2), compared with patients with normal kidney function or mild CKD (eGFR above 60 mL/min/1.73m2).
“Bone densitometry may have clinical utility in risk stratification and identification of patients at high risk of fracture and poor outcomes,” Dr. Afshinnia told Renal & Urology News. “A limitation of densitometry for CKD populations is its inability to differentiate osteoporosis from subtypes of renal osteodystrophy.” Upon identification of at-risk patients, clinicians should conduct individualized assessments and make clinical decisions based on patients' conditions, he suggested. “Further clinical studies are required to delineate the rule of densitometry along with other clinical and laboratory measures in the management of CKD patients.”