Estimated benefits of glycemic control in microvascular complications in type 2 diabetes

Ann Intern Med. 1997 Nov 1;127(9):788-95. doi: 10.7326/0003-4819-127-9-199711010-00003.


Background: The benefits of intensive glycemic control in patients with type 2 diabetes are not well quantified. It is therefore not clear which patients will benefit most from aggressive glycemic control.

Objective: To evaluate the efficacy of glycemic control in type 2 diabetes.

Design: Markov decision model.

Patients: Diabetic patients at a health maintenance organization.

Main outcome measures: Risks for developing blindness and end-stage renal disease; number of patients and patient-years needed to treat to prevent complications.

Results: For a patient in whom diabetes developed before 50 years of age, reducing hemoglobin A1c levels from 9% to 7% results in an estimated 2.3-percentage point decrease (from 2.6% to 0.3%) in lifetime risk for blindness due to retinopathy. The same change in a patient with diabetes onset at 65 years of age would be expected to decrease the risk for blindness by 0.5 percentage points (from 0.5% to < 0.1%). However, the Markov model predicts substantially greater benefit when moving from poor to moderate glycemic control than when moving from moderate to almost-normal glycemic control. Targeting less than 20% of the patients at one health maintenance organization for intensified therapy may prevent more than 80% of the preventable patient-time spent blind. The risks for end-stage renal disease and the risk reduction provided by improved glycemic control are lower than those for blindness.

Conclusions: This probability model, based on extrapolation from the experience with type 1 diabetes, suggests that patients with early onset of type 2 diabetes will accrue substantial benefit from almost-normal glycemic control. In patients with later onset, moderate glycemic control prevents most end-stage complications caused by microvascular disease. These results have important implications for informing patients and allocating health care resources.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Blindness / etiology
  • Blindness / prevention & control
  • Blood Glucose / metabolism*
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / complications*
  • Diabetes Mellitus, Type 2 / therapy
  • Diabetic Angiopathies / etiology
  • Diabetic Angiopathies / prevention & control*
  • Diabetic Retinopathy / etiology
  • Diabetic Retinopathy / prevention & control*
  • Glycated Hemoglobin / metabolism
  • Humans
  • Kidney Failure, Chronic / etiology
  • Kidney Failure, Chronic / prevention & control
  • Markov Chains
  • Middle Aged
  • Risk Factors
  • Sensitivity and Specificity


  • Blood Glucose
  • Glycated Hemoglobin A