Association of urinary albumin:creatinine ratio with incident frailty in older populations

Background The longitudinal relationship of albuminuria with incident frailty remains unknown. Therefore we aimed to evaluate the relation of albuminuria with the risk of incident frailty in older adults. Methods A total of 1115 participants >= 65 years of age (average age 80.3 years) who were free of frailty in the Chinese Longitudinal Healthy Longevity Survey were included. The outcome was incident frailty, defined as a frailty index >= 0.25 during follow-up. Cox proportional hazards models were used to assess the association of the urinary albumin:creatinine ratio (UACR) with frailty. Results During a median follow-up duration of 5.3 years, 295 (26.5%) participants developed incident frailty. Overall, the UACR was significantly positively associated with the risk of incident frailty (P for trend = 0.005), with a significantly higher risk of incident frailty in participants in the quartile 4 of UACR {>= 13.43 mg/g; hazard ratio [HR] 1.64 [95% confidence interval (CI) 1.13-2.37]} compared with those in quartile 1 (<0.73 mg/g). Consistently, when UACRs were assessed as clinical categories, compared with participants with UACR <10 mg/g, those with UACR >= 30 mg/g had a higher HR of incident frailty [HR 1.61 (95% CI 1.17-2.20)]. Accounting for the competing risk of death also did not substantially change the results. In addition, a stronger positive association between UACR and incident frailty was found in those with a higher high-sensitivity C-reactive protein level (hs-CRP) (P for interaction = 0.045). Conclusion Albuminuria was positively associated with the risk of incident frailty, particularly in those with higher hs-CRP, emphasizing the importance of managing both albuminuria and inflammation for primary prevention of frailty.