Moderate chronic kidney disease in women is associated with fracture occurrence independently of osteoporosis.

BACKGROUND

Chronic kidney disease (CKD) is associated with increased risk of fragility fracture but whether this is independent of osteoporosis is unclear.

METHODS

We conducted a retrospective cross-sectional study of 1,702 female patients referred for dual-energy X-ray absorptiometry (DXA) scanning (Lunar IDXA) between September 2006 and April 2007. Estimated glomerular filtration rate (eGFR; ml/min/1.73 m(2)) by Modification of Diet in Renal Disease was calculated within 1 year (median interval 4 weeks) of the DXA scan. The independent association of self-reported fracture occurrence with eGFR category was assessed using multivariate logistic regression.

RESULTS

Mean age (SD) was 61.7 (10.8) years; mean eGFR (SD) was 68.8 (12.2). The percentages of subjects with an eGFR of 75-89, 60-74, 30-59 and <30 was 34, 45, 20 and 0.8%, respectively. Forty-seven percent had osteoporosis. Mean T scores for the above eGFR categories were -2.2, -2.3, -2.5 and -3.0, respectively (p trend <0.001). Osteoporosis was significantly associated with eGFR on univariate analysis but not following adjustment for age. The percentage of patients with a fracture (29%) and with multiple prior fractures (3.5%) was higher at lower eGFR (p < 0.001, χ(2) test). The adjusted odds ratios (95% confidence interval) of any prior fracture for eGFR 75-89, 60-74 and 30-59 were 1.0 (reference), 1.2 (0.9-1.6) and 1.4 (1.0-1.9), respectively, adjusting simultaneously for age, T score, risk factors and treatment for osteoporosis.

CONCLUSION

Moderate CKD is a significant independent predictor of fracture occurrence.