Aim: To determine regional risk factors associated with worsening of diabetic kidney disease (DKD). Methods: We conducted a retrospective longitudinal study using four-year records of a specific health examination among participants with National Health Insurance in Toyooka City (n=5,169 at baseline). Results: A survival analysis with a 20 % increase in the serum creatinine level set as an endpoint revealed that both diabetes mellitus and hypertension are significantly associated with a worsening renal function. Among people with diabetes, an increased HbA1c value or decreased HDL cholesterol levels were associated with worsening of DKD. For those with a high HbA1c (≥8 %), lack of medical treatment for diabetes was associated with a particularly elevated risk. For those with diabetes without macroalbuminuria, reduced HDL cholesterol levels were significantly associated with worsening of DKD. Conclusion: Data from a specific health examination revealed regional risk factors associated with worsening of DKD among participants with National Health Insurance.