The early natural history of albuminuria in young adults with youth-onset type 1 and type 2 diabetes.

AIMS: To determine among adolescents and young adults with youth-onset type 1 diabetes and type 2 diabetes the rates and risk factors for albuminuria regression and progression.

METHODS: Data from SEARCH, a longitudinal observational study of youth-onset type 1 diabetes (N = 1316) and type 2 diabetes (N = 143) were analyzed. Urine albumin:creatinine ratio (UACR) was measured from random urine specimens at baseline and follow-up visits (mean 7 years later). Albuminuria regression was defined as halving of baseline UACR when baseline UACR was ≥30 μg/mg; progression was defined as doubling of baseline UACR when follow-up UACR was ≥30 μg/mg, respectively. Multivariable regression assessed risk factors associated with low-risk albuminuria category (combined persistently-low albuminuria and regression) versus moderate-risk albuminuria category (combined persistently-high albuminuria and progression).

RESULTS: Albuminuria progression was more common in type 2 diabetes versus type 1 diabetes (15.4% versus 6.0%, p<0.001). Moderate-risk albuminuria was associated with increasing HbA1c (adjusted OR (aOR) = 1.3, 95% CI 1.1-1.6) and lack of private health insurance (aOR = 2.7, 95%CI 1.1-6.5) in type 1 diabetes; and African American race (OR = 4.6, 95% CI 1.2-14.2), lower estimated insulin sensitivity score (aOR = 2.1, 95% CI 1.4-3.3), baseline UACR (aOR = 3.2, 95% CI 1.7-5.8), and follow-up estimated glomerular filtration rate (eGFR) (10-unit increase aOR = 1.3, 95% CI 1.0, 1.5) in type 2 diabetes.

CONCLUSIONS: In the first decade of diabetes duration, kidney complications in type 2 diabetes are significantly more aggressive than in type 1 diabetes and may be associated with less modifiable risk factors including race, insulin sensitivity, and eGFR. Early interventions may help reduce long-term kidney complications.