OBJECTIVE

To elucidate the association of glomerular filtration rate (GFR) at baseline with subsequent progression of albuminuria in individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a single-center retrospective cohort study of 6,618 Japanese adults with type 2 diabetes and urinary albumin-to-creatinine ratio of <300 mg/g, comprising 2,459 women and 4,159 men with a mean (± SD) age of 60 ± 12 years. The exposure was baseline estimated GFR (eGFR) (mL/min/1.73 m2), treated as a categorical variable and classified into five categories: ≥90, 75–90, 60–75, 45–60, and <45, as well as a continuous variable. The outcome was progression of albuminuria category (i.e., from normoalbuminuria to micro- or macroalbuminuria or from micro- to macroalbuminuria). Hazard ratios (HRs) for the outcome were estimated using the multivariable Cox proportional hazards model. In the analysis treating baseline eGFR as a continuous variable, the multivariable-adjusted restricted cubic spline model was used.

RESULTS

During the median follow-up period of 6.3 years, 1,190 individuals reached the outcome. When those with a baseline eGFR of 75–90 mL/min/1.73 m2 were considered the reference group, HRs (95% CIs) for the outcome in those with a baseline eGFR of ≥90, 60–75, 45–60, or <45 mL/min/1.73 m2 were 1.38 (1.14–1.66), 1.34 (1.14–1.58), 1.81 (1.50–2.20), or 2.37 (1.84–3.05), respectively. Furthermore, the inverse J-shaped curve was more clearly shown by the spline model.

CONCLUSIONS

This study of Japanese adults with type 2 diabetes suggests that both high and low GFRs are implicated in the pathogenesis of albuminuria progression.

ARTICLE HIGHLIGHTS

  • Glomerular hyperfiltration may induce kidney damage.

  • We asked whether glomerular filtration rate (GFR) is associated with subsequent development and progression of albuminuria in people with diabetes.

  • This retrospective cohort study of 6,618 adults with type 2 diabetes has shown that both an estimated GFR (eGFR) ≥90 mL/min/1.73m2 and an eGFR <75 mL/min/1.73m2 at baseline were risk factors for the subsequent category progression of albuminuria.

  • This study suggests that both a high and low GFR are implicated in the pathogenesis of albuminuria development and progression in people with diabetes.

This article contains supplementary material online at https://doi.org/10.2337/figshare.21399495.

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