Ratio of urine albumin to creatinine attenuates the association of dementia with hip fracture risk

Context: Microvascular disease is a leading cause of cognitive impairment. Approximately 50% of people with a hip fracture have cognitive impairment.

Objective: We tested the hypothesis that microvascular diseases of the brain (lacunar infarcts and white matter disease [WMD]), kidney (albuminuria [≥30 mg/g creatinine] and albumin creatinine ratio [ACR]), and eye (retinal vascular disorders) attenuate the association of cognitive impairment with hip fracture risk.

Setting: The Cardiovascular Health Cognition Study.

Patients: Three thousand, one-hundred six participants (mean age, ∼ 79 y; 8.84 y median follow-up) with cognitive testing. Subsets received ACR testing (n=2389), brain magnetic resonance imaging scans (n= 2094), and retinal photography (n= 1098).

Main Outcome Measure: Incident hip fracture.

Results: There were 488 participants (16%) with mild cognitive impairment (MCI) and 564 (18%) with dementia. There were 337 incident hip fractures, of which 19% occurred in participants with MCI and 26% in participants with dementia. Adjusted hazard ratios (HR) and 95% confidence interval for hip fracture in participants with MCI were 2.45 (1.67-3.61) and for dementia 2.35 (1.57-3.52). With doubling of ACR, the HR for fracture was attenuated in participants with dementia compared with participants with normal cognition [interaction HR 0.70 (0.55-0.91)]. No such effect was found in participants with MCI. Albuminuria, lacunar infarcts, WMD, and retinal vascular disease (RVD) did not modify the association of dementia or MCI with hip fracture risk.

Conclusions: ACR attenuates part of the risk of hip fracture in people with dementia, suggesting that these disorders share a common pathogenesis.