Abstract
AIMS/INTRODUCTION: Diabetic kidney disease is characterized by increased albuminuria and/or a reduced glomerular filtration rate (GFR). We analyzed secular changes in the prevalence of albuminuria and reduced estimated GFR (eGFR) in Japanese patients with type 2 diabetes, and identified factors associated with these changes. MATERIALS AND METHODS: Using 1996, 2001, 2006 and 2014 cohort data from the Japanese serial cross-sectional studies conducted at Shiga University of Medical Science, secular changes in the prevalence of diabetic kidney disease (albuminuria and/or reduced eGFR), patient characteristics and their associations were analyzed. RESULTS: The prevalence of microalbuminuria and macroalbuminuria decreased over time, whereas the prevalence of moderately reduced eGFR (30-60 mL/min/1.73 m(2) ) and severely reduced eGFR (<30 mL/min/1.73 m(2) ) increased. Severely reduced eGFR was observed mainly in the patients with macroalbuminuria, regardless of year. Conversely, the prevalence of moderately reduced eGFR increased in the patients without macroalbuminuria. Both macroalbuminuria and moderately reduced eGFR without macroalbuminuria in the 2014 cohort were refractory to the recently recommended intensive therapy. Finally, we showed that obesity accompanied by vascular dysfunction was a risk factor for the development of albuminuria, and that age-dependent arterial stiffness was associated with reduced eGFR without macroalbuminuria in the 2014 cohort. CONCLUSIONS: During the past 20 years in Japan, the prevalence of albuminuria declined, whereas that of reduced eGFR increased. Additionally, obesity- and high age-related vascular damage seems to be associated with macroalbuminuria and reduced eGFR without macroalbuminuria, respectively.