Albuminuria, glomerular filtration rate, and fracture among U.S. adults with and without type 2 diabetes

ABSTRACT Chronic kidney disease (CKD) and type 2 diabetes (T2D) are established risk factors for fracture. Albuminuria and reduced estimated glomerular filtration rate (eGFR), the most commonly used measures to diagnose CKD, may confer fracture risk through distinct mechanisms. Clarifying the associations of albuminuria, reduced eGFR, and T2D status with fracture risk and potential interactions between these exposures may improve fracture risk assessment. We performed a cross-sectional study of 20,034 participants 50 years or older in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2020. Albuminuria was defined by spot urine albumin-to-creatinine ratio >30 mg/g; reduced eGFR was defined as <60 mL/min/1.73m2. Outcomes were prevalent hip and any fracture—the composite of any hip, wrist, or spine fracture—ascertained using self-report of physician diagnosis. Mean age was 63 years; 53% were female, 9% were non-Hispanic Black, and 5% were Mexican-American. Participants reported 417 hip and 2,703 any fractures. After adjusting for demographic and clinical covariates, including osteoporosis diagnosis and treatment, albuminuria was associated with increased odds of hip fracture (OR 1.59, 95% CI: 1.13, 2.22), with no significant interaction by eGFR or T2D status. Neither reduced eGFR (OR 1.02; 95% CI: 0.73, 1.44) nor T2D status (OR 0.94; 95% CI: 0.63, 1.39) was associated with higher odds of hip fracture. Albuminuria, reduced eGFR, and T2D were not significantly associated with any fracture. In a subset of 7,005 participants with bone mineral density (BMD) measurements, additional adjustment for femoral neck BMD partially attenuated the association of albuminuria with hip fracture (OR 1.35; 95% CI: 0.72, 2.53). In conclusion, albuminuria is associated with hip fracture in adults with and without T2D, independent of eGFR.