Dr Aftab Ahmad Consultant Diabetologist at Royal Liverpool University Hospital Regional Diabetes Network Lead

Dr Aftab Ahmad Consultant Diabetologist at Royal Liverpool University Hospital Regional Diabetes Network Lead

Today s Presentation HbA1c & diagnosing Diabetes What is Impaired Glucose & IGR? Implications of IGR! Can we manage it? Regional Diabetes Network s Role Is it cost effective to manage it?

WHO 2005 Recommendation 1. The previous (1999) WHO diagnostic criteria should not be changed. 2. The diagnostic cut-point for IFG (6.1 mmol/l) should not be changed. 3. HbA1c should not be adopted as a diagnostic test, as the challenges of measurement accuracy outweighed the convenience of its use.

2011 Recommendation By WHO 1. HbA1c can be used as a diagnostic test for diabetes providing that: stringent quality assurance tests are in place and assays are standardised to criteria aligned to the international reference values. and there are no conditions present which preclude its accurate measurement.

Recommendation By WHO 1. An HbA1c of 6.5% is recommended as the cut point for diagnosing diabetes. 2. A value of less than 6.5% does not exclude diabetes diagnosed using glucose tests.

Rationale for using HbA1c Similar relationship between HbA1C and risk of retinopathy as with FPG and 2-h PG.

Prevalence of diabetes-specific retinopathy ( moderate non proliferative retinopathy) by vigintiles* of distribution of FPG, 2-h PG and HbA1c from DETECT-2.

Prevalence of retinopathy by 0.5 mmol/l intervals for FPG and 2-h PG and by 0.5% intervals for HbA1c for any retinopathy and diabetes-specific retinopathy ( moderate NPDR) from DETECT-2

Advantages of using HbA1c The A1C has several advantages to the FPG and OGTT; including greater convenience (since fasting is not required), evidence to suggest greater preanalytical stability, and less day-to-day perturbations during periods of stress and illness.

Disadvantages of using HbA1c These advantages must be balanced by: greater cost, the limited availability of A1C testing in certain regions of the developing world, the incomplete correlation between A1C and average glucose in certain individuals. In addition,hba1c levels may vary with patients race/ethnicity

Other considerations for HbA1c HbA1C of 6.5% identifies 1/3rd fewer cases of undiagnosed diabetes than a FPG of 7.0 mmol/l. However greater practicality and wider application of a more convenient test (A1C) may increase the number of diagnoses made.

Criteria for the diagnosis of HbA1C 6.5% (48mmol/mol). OR FPG 7.0 mmol/l. Fasting is defined as no caloric intake for at least 8 h. OR 2-h plasma glucose 11.1mmol/L during an OGTT. OR diabetes In a patient with classic symptoms of hyperglycemia or hyperglycemic crisis, a random plasma glucose 11.1 mmol/l.

Criteria for testing for diabetes in asymptomatic adult individuals Testing should be considered in all adults who: are overweight (BMI=25) have one or more additional risk factors: physical inactivity first-degree relative with diabetes high-risk race/ethnicity (e.g., African American, Latino, Native American, Asian American, Pacific Islander) women who delivered a baby weighing.9 lb or who were diagnosed with GDM hypertension (blood pressure 140/90 mmhg or on therapy for hypertension) HDL cholesterol level 0.90 mmol/l and/or a triglyceride level 2.82 mmol/l women with PCOS A1C 5.7%, IGT, or IFG on previous testing other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans) history of CVD In the absence of the above criteria, testing at age 45 years. If results are normal, testing should be repeated at least at 3-year intervals.

Interpretation if two different tests are available and the results are discordant: the test whose result is above the diagnostic cut point should be repeated, and the diagnosis is made on the basis of the confirmed test. That is, if a patient meets the diabetes criterion of the A1C (two results 6.5%) but not the FPG (7.0 mmol/l), or vice versa, that person should be considered to have diabetes.

IGR

So what is IGR? (Prediabetes) Individuals with IFG and/or IGT have been referred to as having IGR or prediabetes, indicating; the relatively high risk for the future development of diabetes & CVD. IFG and IGT are associated with: obesity dyslipidemia high triglycerides Low HDL cholesterol, hypertension.

ADA s Categories of increased risk for diabetes (prediabetes) FPG 5.6 mmol/l to 6.9 mmol/l (IFG) OR 2-h glucose in OGTT 7.8-11.0 mmol/l (IGT) OR A1C 5.7 6.4% (6.0%-6.5% by WHO)

ADA/WHO position on IGR Diabetes and lesser forms of glucose intolerance, impaired glucose tolerance (IGT) and impaired fasting glucose (IFG), can now be found in almost every population in the world and epidemiological evidence suggests that, without effective prevention and control programmes, the burden of diabetes is likely to continue to increase globally.

Implication of IGR Studies show a strong, continuous association between HbA1C and subsequent diabetes. In a systematic review of 44,203 individuals from 16 cohort studies; those with an HbA1C between 5.5 and 6.0% had a substantially increased risk of diabetes with 5-year incidences ranging from 9 25%. An HbA1C range of 6.0 to 6.5% had a 5-year risk of developing diabetes between 25 to 50% and relative risk 20 times higher compared with an A1C of 5.0%.

ADA s PREVENTION/DELAY OF TYPE 2 DIABETES Patients with IGT, IFG, or an A1C of 5.7 6.4% (IGR) should be referred to an effective ongoing support program targeting: weight loss of 7% of body weight increasing physical activity to at least 150 min per week of moderate activity. Follow-up counseling appears to be important for success. Based on the cost-effectiveness of diabetes prevention, such programs should be covered by third-party payers.

ADA s PREVENTION/DELAY OF TYPE 2 DIABETES Metformin therapy for prevention of type 2 diabetes may be considered in those with IGR, especially for those with: BMI >35 kg/m2, age 60 years, women with prior GDM. At least annual monitoring for the development of diabetes in those with prediabetes is suggested.

Regional Diabetes Network s Role Standardise management plans across the region. Develop & help implement pathways. Support CCGs strategic visions. Develop local solutions for local problems. IGR pathway is a prime example.

Merseyside IGR Pathway Identify High Risk Patients (Box 1) HbA1c < 42 mmol/mol 42-47 mmol/mol 48 mmol/mol (without symptoms) 48 mmol/mol (with symptoms) h/o GDM No h/o GDM IGR Repeat HbA1c within 2 weeks 48 mmol/mol Clinical/lifesty le review (Box 2) normoglyca emia Register of IGR & h/o GDM Diabetes Mellitus Healthy lifestyle advice Clinical/life style review (Box 2) North Mersey Pathway Self care (Box 3) IGR education (Box 4) Lifestyle referral (Box 5)

Merseyside IGR Pathway < 42 mmol/mol Identify High Risk Patients 42-47 mmol/mol h/o GDM No h/o GDM HbA1c IGR normoglycaemia Register of IGR & h/o GDM Healthy lifestyle advice Clinical/lifestyle review Register of IGR & h/o GDM Self care IGR education Lifestyle referral

BMI. 28 (or >24.5 in South Asians) Stage 1 Hypertension. Increased waist circumference. Family h/o T2 DM. H/o GDM Box-1 Individual Risk Factors

Box-2 CVD risk assessment Measurements Lifestyle assessments Pharmacological review Preconception counselling Annual HbA1c & above.

Box-3 & 4 Self Care & IGR education Local resource will be developed

DETECTION AND DIAGNOSIS OF GESTATIONAL DIABETES MELLITUS (GDM) Screen for undiagnosed type 2 diabetes at the first prenatal visit in those with risk factors, using standard diagnostic criteria. In pregnant women not previously known to have diabetes, screen for GDM at 24 28 weeks gestation, using a 75-g 2-h OGTT and the diagnostic cut points in Table 6. Screen women with GDM for persistent diabetes at 6 12 weeks postpartum, using a test other than A1C. Women with a history of GDM should have lifelong screening for the development of diabetes or prediabetes at least every 3 years. Women with a history of GDM found to have prediabetes should receive lifestyle interventions or metformin to prevent diabetes.