Screening, diagnosis and classification of diabetes A. Prof Jonathan Shaw Associate Director Baker IDI Melbourne

Page 2: Baker IDI Identifying people at risk of developing type 2 diabetes Test everyone – mass screening Test people who have risk factors for diabetes Undertake large-scale, non-invasive, self completed screening, with a validated tool, followed by blood tests for those at high-risk –FINDRISK –AUSDRISK AUSDRISK Self-completed risk score Developed and validated on Australian data Calculates 5-yr risk of developing diabetes

Page 3: Baker IDI

Page 4: Baker IDI 1. Your age group? Under 35 years 0 pts 35 – 44 years 2 pts 45 – 54 years 4 pts 55 – 64 years6 pts 65 years or over 8 pts 2. Your gender? Female 0 pts Male 3 pts

Page 5: Baker IDI 3. Ethnicity/Country of birth: 3a. Are you of Aboriginal, Torres Strait Islander, Pacific Islander or Maori descent? No 0 pts Yes 2 pts 3b. Where were you born? Australia0 pts Asia2 pts Mid-East, N Africa2 pts S Europe 2 pts Other 0 pts

Page 6: Baker IDI 4. Have either of your parents, or any of your brothers or sisters been diagnosed with diabetes (type 1 or type 2)? No 0 pts Yes 3 pts 5. Have you ever been found to have high blood glucose (sugar) (e.g. in a health examination, during an illness, during pregnancy)? No 0 pts Yes 6 pts

Page 7: Baker IDI 6. Are you currently taking medication for high blood pressure? No 0 pts Yes 2 pts 7. Do you currently smoke cigarettes or any other tobacco products on a daily basis? No 0 pts Yes 2 pts

Page 8: Baker IDI 8. How often do you eat vegetables or fruit? Everyday 0 pts Not everyday 1 point 9. On average, would you say you do at least 2.5 hours of physical activity per week (eg 30 minutes a day on 5 or more days a week)? Yes 0 pts No 2 pts

Page 9: Baker IDI 10. Your waist measurement taken below the ribs (usually at the level of the navel)? For those of Asian or Aboriginal or Torres Strait Islander descent: Men Women < 90 cm < 80 cm 0 pts 90 – 100 cm 80 – 90 cm 4 pts >100 cm > 90 cm 7 pts For all others: Men Women < 102 cm < 88 cm 0 pts 102 – 110 cm 88 – 100 cm 4 pts > 110 cm > 100 cm 7 pts

Page 10: Baker IDI Your risk of developing type 2 diabetes within 5 years: ≤ 5: Low risk Approximately one person in every 100 will develop diabetes. 6-14: Intermediate risk For scores of 6-8, approximately one person in every 50 will develop diabetes. For scores of 9-14, approximately one person in every 20 will develop diabetes. 15 or more: High risk For scores of 15-19, approximately one person in every seven will develop diabetes. For scores of 20 and above, approximately one person in every three will develop diabetes.

Diagnostic criteria for diabetes

Page 12: Baker IDI Diagnostic thresholds should be defined by Their association with clinically meaningful abnormalities Level above which intervention is effective Associations with intermediate (metabolic) disturbances Normal limits of a healthy population –mean + 2SD –9?th percentile Bimodal distribution

Page 13: Baker IDI Cut-points for diabetes based on Identifying a glucose threshold for the presence of complications Bi-modal distribution of blood glucose

Page 14: Baker IDI Cut-points for diabetes based on Identifying a glucose threshold for the presence of complications Bi-modal distribution of blood glucose

Relative risk of CVD mortality by 2-hr glucose - DECODE Relative risk hour plasma glucose (mmol/l) <3.0 >14.5 Normal IGT Diabetes

Pima Egypt US - NHANES Range of FPG thresholds ADA. D Care 1997;20:

Limitations of associations with complications Thresholds have been based on micro- not macrovascular disease Estimates of threshold values are imprecise (variation between populations, wide limits of deciles) All data are cross-sectional – longitudinal analyses would be likely to give lower cut-points ‘Diabetic retinopathy’ occurs at non-diabetic glucose levels Studies need to have more cases of retinopathy, and be able to use more severe levels of retinopathy

Page 18: Baker IDI HbA 1C for DIAGNOSIS PROStable Time averaged Reproducible Fasting not required CONStandardisation essential Expensive Not freely available Problems with anaemia, haemoglobinopathies Poor QA schemes in many countries Few data available Cutpoint uncertain

Page 19: Baker IDI P revalence of Sickle cell disorders

Page 20: Baker IDI PLASMA GLUCOSE for DIAGNOSIS PRODM is disorder of raised glucose Time honoured Much data Allows international comparisons Accurate assay (?) CONBased on cross-sectional data in relatively small numbers of studies Major pre-analytical problems OGTT required – FPG inadequate Often poor QA

Page 21: Baker IDI Diabetes Care July 2009 Recommends using HbA1c as the preferred diagnostic test for diabetes at a cut-point of 6.5%

Classification of diabetes

Page 23: Baker IDI WHO reports on classification 1965, 1980, 1985, 1998, 2006

Page 24: Baker IDI POSSIBLE 2009 WHO CLASSIFICATION OF DIABETES MELLITUS 1.Type 1 diabetes (  -cell destruction) 2.Type 2 diabetes 3.Other specific types 4.Gestational diabetes mellitus 5.Undefined ADA, WHO, 1997

Classic Onset Type 1 Age of onset Usually under 30Usually Usually over 30 years (except for MODY) Present- ation Rapid onset of thirst, polyuria, weight loss Gradual onset of milder symptoms Often asymptomatic; may present with complications or gradual onset of symptoms. 85% obese. Part of Metabolic Syndrome. Ketonuria Usually presentMay be absentAbsent (except with severe stress eg infection, infarction) Anti-GAD antibodies Present in approx 80% at diagnosis C-peptide level Low or absent, but may be low-normal initially (remission phase) Normal-high (ie hyperinsulinemia) Treatment Insulin required urgently to prevent ketoacidosis Insulin required, but not urgently Healthy eating and exercise, may require oral agents, and/or insulin later Classic Onset Type 1Slow Onset Type 1 (LADA) Type 2 Absent

Page 26: Baker IDI Summary Screening –Begin with non-invasive score –Blood testing in those with a high score Diagnosis –HbA1c may become an accepted test –Clinical diagnosis requires confirmation with a 2 nd test Classification –Differentiation between type 1 and 2 increasingly difficult –For most patients, classification, and need for insulin can be determined on simple, clinical criteria

Page 27: Baker IDI Summary Screening –Begin with non-invasive score –Blood testing in those with a high score Diagnosis –HbA1c may become an accepted test –Clinical diagnosis requires confirmation with a 2 nd test Classification –Differentiation between type 1 and 2 increasingly difficult –For most patients, classification, and need for insulin can be determined on simple, clinical criteria

Page 28: Baker IDI Summary Screening –Begin with non-invasive score –Blood testing in those with a high score Diagnosis –HbA1c may become an accepted test –Clinical diagnosis requires confirmation with a 2 nd test Classification –Differentiation between type 1 and 2 increasingly difficult –For most patients, classification, and need for insulin can be determined on simple, clinical criteria

Page 29: Baker IDI Summary Screening –Begin with non-invasive score –Blood testing in those with a high score Diagnosis –HbA1c may become an accepted test –Clinical diagnosis requires confirmation with a 2 nd test Classification –Differentiation between type 1 and 2 increasingly difficult –For most patients, classification, and need for insulin can be determined on simple, clinical criteria

Some things are more complicated than screening and diagnosing diabetes!