Association of Albuminuria Within the Normoalbuminuric Range With All-Cause Mortality in People With Type 2 Diabetes.

AIMS: To investigate the independent association of albuminuria within the normoalbuminuric range with all-cause mortality in normoalbuminuric people with type 2 diabetes with and without chronic kidney disease (CKD).

MATERIALS AND

METHODS

This observational, prospective, multicentre, cohort study enroled 15,773 individuals with type 2 diabetes in 2006-2008. At baseline, albumin excretion rate (AER) and estimated glomerular filtration rate (eGFR) were assessed together with cardiometabolic risk profile, treatments, complications, and comorbidities. All-cause mortality was verified on 31 October 2015.

RESULTS

Of the 15,656 participants (99.3%) with valid information on vital status, 11,460 (71.2%) were normoalbuminuric, 9984 (87.1%) without and 1476 (12.9%) with CKD. Normoalbuminuric individuals were stratified into three (< 5, 5-15, and > 15 mg·day-1) or two (< 10 and 10-29 mg·day-1) AER subcategories. When adjusting for age, sex, eGFR, prior cardiovascular disease, cardiovascular risk factors, and treatments, mortality risk was higher in participants with AER 10-29 versus < 10 mg·day-1 (hazard ratio, 1.120 [95% confidence interval, 1.028-1.221], p = 0.009) and 15-29 versus < 5 mg·day-1 (1.243 [1.099-1.406], p < 0.0001). When stratifying by CKD status, the adjusted risk remained significantly increased only for AER 15-29 versus  < 5 mg/24 h in individuals with (1.404 [1.111-1.774], p = 0.005) and, to a lesser extent, without (1.167 [1.009-1.350], p = 0.038) CKD. A non-linear association was observed between AER as Log2 transformed continuous variable and mortality.

CONCLUSIONS

For the same level of kidney function, higher AER within the normoalbuminuric range was independently associated with all-cause mortality, thus supporting to the use of albuminuria-lowering drugs in people with type 2 diabetes and mildly elevated albuminuria.

TRIAL REGISTRATION: ClinicalTrials.gov, NCT00715481, retrospectively registered 15 July, 2008.