The epidemic of pre-diabetes: the medicine and the politics

Summary box

• Clinical context—Attempts to tackle the increasing prevalence of diabetes have focused on identifying and treating people at risk of developing the disease

• Diagnostic change—The definition of people at risk has expanded from impaired glucose tolerance to include people with raised fasting glucose or glycated haemoglobin (HbA_1c) concentrations and cut-off points have been lowered

• Rationale for change—People in all the above categories have a raised diabetes risk, although prediction is poorer for fasting glucose and HbA_1c than for impaired glucose tolerance

• Leap of faith—Treatment of people in newly defined categories will improve mortality and morbidity

• Impact on prevalence—The expanded categories increase the prevalence of pre-diabetes by twofold to threefold

• Evidence of overdiagnosis—New definitions result in over 50% of Chinese adults having pre-diabetes

• Harms from overdiagnosis—A label of pre-diabetes bring problems with self image, insurance, and employment as well as the burdens and costs of healthcare and drug side effects

• Limitations of evidence—No studies have examined the effect of lifestyle or drug interventions in newly added subcategories

• Conclusion—Diabetes prevention requires changes to societies and therefore a concerted global public health approach. Diagnoses and thresholds for clinical application may unrealistically burden societies in exchange for limited value