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The CDA Expert Committee has published a revised set of evidence-based Clinical Practice Guidelines in 2008. These were published in the Canadian Journal of Diabetes, Sept 2008, Vol 32, Suppl 1. DIAGNOSIS . Or Casual PG >=11.1 mmol/L + symptoms of diabetes Or 2hPG in a 75-g OGTT >=11.1 mmol/L A confirmatory lab glucose must be done in all cases on another day in the absence of unequivocal hyperglycemia accompanied by acute metabolic decompensation Screening for diabetes using an FPG should be performed every 3 years in individuals >=40 years of age. FPG is the recommended screening test. A 2hrPG in a 75-g OGTTis indicated when FPG is 6.1 to 6.9 (and may be indicated when FPG is 5.6 to 6.9 mmol/L and suspicion of IGT is high) i.e: those in high risk groups such as:
Dysglycemias: IGT (Post Prandial Glucose 7.8-11) and IFG (Fasting Glucose 6.1-7.0) are different conditions. IGT is caused primarily by Insulin Resistance and the pathology is decreased glucose uptake by muscle. It tends to occur in younger individuals. IFG involves pancreatic insufficiency and liver overproduction of glucose, patients tend to be older. The Fumagata study has shown that IGT is more predictive of Macrovascular (Cardiovascular) disease than IFG. Individuals with IGT have cardiovascular disease risks very close to diabetics. Of those with IFG; 1/3 are normal, 1/3 have IGT and 1/3 have diabetes on OGT. Those with IFG (FBS 5.7 to 7.0) should have a 75 gm oral glucose tolerance test with a 2 hr PC glucose since the DECODE study has shown that the Fasting Glucose test misses many people who would be diagnosed with Diabetes on the 2 hr PC sample. The evidence suggests that IFG should be defined as Fasting Glucose of 5.7 to 6.9. A fasting glucose of 5.7 equates to a post prandial glucose of 7.8 and a post prandial glucose of 7.8 increases the relative risks of cardiovascular disease by 1.5. In the Kumamato study, those with an A1C >6.5 had progression of disease. Incidence of Retinopathy increases with Fasting Glucose greater than 6.5. In the DECODE study, increased risk of MI and mortality were seen with Post Prandial Glucose levels over 10. Glycemic Control: Both FBS & PPG correlate with the risk of complications. TARGETS: A1c <7% Pre meal Glucose 4-7 mmol/L Post Prandial 5-10 mmol/L (5-8.0 mmol/L if A1c targets are not being met Kumamato study: Retinopathy & Nephropathy start at A1C 7% UKPDS: 1% decrease in A1c reduced any endpoint by 21% Deaths by 21% All Cause Mortality 14% ACCORD study showed increase in death in the intensive control arm with target A1C <6% Normoglycemia may not be an appropriate goal in those at risk of severe hypoglycemia. PHARMACOLOGIC MANAGEMENT OF TYPE 2 DIABETES
Initial use of combinations of sub maximal doses of antihyperglycemic agents produces more rapid & improved glycemic control compared to monotherapy at maximal doses. When combining agents, classes with different mechanisms of action should be used. How we reach target may be less important than the need to achieve that target.
Incidence of hypoglycemia increases as glucose targets fall. Repeated hypoglycemia leads to defective counter regulation and hypoglycemic unawareness. These defects are reversible with avoidance of hypoglycemia. Metformin, Acarbose, DPP-4 and Thiazolidenediones are associated with no significant hypoglycemia. Secretagogues & Insulin associated with more hypoglycemia. Elderly more at risk. The initial agent should be Metformin. In the elderly Sulphonylureas should be used with caution and Gliclazide (Diamicron) or Glimepiride (Amaryl) is preferable to Glyburide. Treatment of Hypoglycemia:15 gm Carbohydrate; wait 15 minutes to retreat.
Lipids and Macrovascular Disease: 80% of Diabetics will die of macrovascular disease. In 1998, Steve Haffner showed that the diabetic who has not had a heart attack has the same risk as a non diabetic who has had a heart attack; we therefore classify diabetics in the very high risk category. The risk reduction benefit of lipid lowering in diabetics is even greater than in non diabetics. In the Heart Protection Study 6000 of subjects were diabetic and statin treatment gave a 25% reduction in cardiovascular events. In the CARDS study 10 mg atorvastatin reduced CV events by 40% in diabetics with normal LDL. The Helsinki Heart Study showed significant risk reductions with fibrates. The VA-HIT study showed a 24% event reduction with fibrates and the DAIS showed reduced progression of atherosclerosis with fibrates. FIELD study showed non significant benefit with Fibrate. First choice is statin. Lipids should be measured at diagnosis of diabetes & annually. Lipid Goals: Most diabetics are considered at high risk for cardiovascular disease.
Start treatment with a statin if LDL>2.0 Start treatment with a fibrate if Trig >10 Early aggressive treatment to goal including several agents if necessary In view of HPS & CARDS data, consider statin treatment in those over 40 or with clinical evidence of vascular disease even if LDL <2. Normal Triglyceride is <1.5, Fibrate if >10 to decrease risk of pancreatitis. Blood Pressure: Goal <130/80
Renal Function: Screening for CKD should be done with creatinine and Glomerular Filtration Rate (eGFR) calculated and ACR (Albumen/Creatinine Ratio) normal <2 for men and <2.8 for women. Urine Albumen/Creatinine should be done within 5 years for Type 1 and at diagnosis for Type 2, then annually. Those with ACR >60 mg/mmol, or eGFR <30 ml/min should be referred to a Nephrologist. Diabetes with ACR >2 for men, >2.8 for women should be on ACE or ARB. Thiazide diuretic for salt & water retention Consider stopping ACE/ARB/DIURETIC for acute illness or dehydration Avoid pregnancy while on ACE/ARB. Pregnancy: Pre-Pregnancy A1C should be <7%. Discontinue oral agents and start intensive insulin pre-conception. Glyburide or Metformin may be used if insulin refused. Ketosis should be avoided. Try to maintain pre-pregnancy body mass. GDM: should be screened with 50gm OGTT between 24 & 28 weeks gestation. If 1 hr PG >10.3 diagnose GDM If 1 hr PG 7.8-10.2 do 75 gm OGTT Screen at first pre-natal visit if high risk (e.g. BMI >30) Diagnostic Criteria at 75 gm OGTT Fasting >5.3 1 hr PC >10.6 2 hr PC >8.9 if any two of these are exceeded, diagnose GDM, if 1 is high IGT of pregnancy 6 weeks post partum follow up with OGTT and Lipids Remember GDM is high risk for subsequent development of Type 2 Diabetes Mellitus.
Changes from 2003 Guidelines
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