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Diabetes & Its Relevance to Retinopathy Screening

Diabetes & Its Relevance to Retinopathy Screening. Dr John Doig Consultant Diabetologist DRS Clinical Lead Forth Valley. Diabetes & Its Relevance to Retinopathy Screening. What is diabetes Diagnosis Types of Diabetes Treatment Complications Acute metabolic Macrovascular Microvascular

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Diabetes & Its Relevance to Retinopathy Screening

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  1. Diabetes & Its Relevance to Retinopathy Screening Dr John Doig Consultant Diabetologist DRS Clinical Lead Forth Valley

  2. Diabetes & Its Relevance to Retinopathy Screening • What is diabetes • Diagnosis • Types of Diabetes • Treatment • Complications • Acute metabolic • Macrovascular • Microvascular • Managing Risk Factors

  3. What is Diabetes Mellitus • Diabetes = excessive production of urine • mellitus = honeyed • Life-long illness associated with various complications • Blindness • Heart disease • Kidney disease • Damage to the feeling in the limbs (peripheral neuropathy).

  4. Diabetes Mellitus • characterised by high blood sugar levels, disturbances of carbohydrate, fat and protein metabolism • absolute lack or a relative deficiency in insulin action and/or insulin secretion • Prevalence increasing • Scottish Survey 2001 = 2.1 % • Forth Valley 2006 = 4.1 % • Some practices = 5.0 %

  5. Management of Diabetic Patient • Main Issues • Diagnosis • Glycaemic Control • Screening • Microvascular Complications • Macrovascular Complications • Diabetes related issues / Education • Driving, Work, Pregnancy • Injection sites, Diet, Monitoring

  6. Diagnosis • Symptoms • Osmotic Symptoms & Fatigue • Weight loss / gain • Infection • Neuropathic Symptoms • Visual Upset • Cardiovascular symptoms

  7. Diagnosis: Diagnostic Criteria Fasting Plasma Glucose >7.0 (on 2 occasions*) Random Plasma Glucose >11.1 (on 2 occasions*) (1 occasion if symptomatic) Fasting Plasma Glucose 6.1 - 6.9 = IFG 2 hr post 75g glucose 7.8 - 11.1 = IGT 2 hr post 75g glucose > 11.1 = DM

  8. Type I Young < 35 Thin + weight loss Rapid onset Ketonuria Autoimmune B Cell failure Insulin Dependent Type 2 Older > 35 Overweight Onset months Strong FH Complications Insulin resistance Late B Cell failure Hyperinsulinaemia Metabolic syndrome Cardiovascular Disease Type of Diabetes

  9. Other types of Diabetes • Gestational • Drug induced • Steroids, Atypical Neuroleptics • Metabolic • Haemachromatosis, Cushings, Acromegaly • Pancreatic disease • MODY (Genetic) • Stress hyperglycaemia

  10. Treatment • Diet • Oral Hypoglycaemic Agents • Sulphonylureas • Biguanides • Alpha 1 glucosidase inhibitors • Thiazolidinediones(Glitazones or Insulin sensitisers) • Exenatide GLP-1 agonists • DPP4 Inhibitors Gliptins • Insulin • Soluble, Biphasic, Intermediate / Long acting

  11. Acute Metabolic Complications • Diabetic Ketoacidosis • Hyper Osmolor Nonketotic Coma • Lactic Acidosis • Hypoglycaemia

  12. Hypoglycaemia • Common side effect of Insulin or Sulphonylureas • Does not occur with Metformin, Acarbose or TZD’s • Minor hypos often go unreported (Self treated) • Severe hypos occurs in 25-30 % of patients each year • Coma occurs in ~ 10 % of patients each year

  13. Causes of hypoglycaemia

  14. Risk factors for severe hypoglycaemia • Insulin treatment regimen Intensified High insulin doses • Impaired awareness of hypoglycaemia Acute (Preceding hypoglycaemic episodes) Chronic (Central autonomic failure) • Long duration of diabetes • Increasing age of patient • Sleep, Excessive alcohol consumption

  15. Morbidity of hypoglycaemia • CNS Coma and Convulsions Transient motor deficits Permanent brain damage Cerebral Oedema • CVS Arrhythmia Myocardial ischaemia Stroke • Fractures, Vitreous haemorrhage

  16. Treatment of hypoglycaemia • Treated immediately by oral glucose 10-20 g • If unable to swallow then • Intravenous glucose 50ml 20% • Intravenous glucose 25ml 50 % • Subcutaneous glucagon 1 mg • Patients usually recover within minutes • Failure to do so may be due to cerebral oedema • On recovery encourage consumption of complex carbohydrate • Identify cause & take appropriate action / patient to contact diabetes care team.

  17. Macrovascular Complications • Coronary Artery Disease • Peryipheral Vascular Disease • Cerebro Vascular Disease • Hyperlipidaemia • Hypertension • Obesity

  18. 20 15 10 5 0 0 1 2 3 4 4.75 Relative Risk = -32% (95% CI -45, -15) p=0.001 Cumulative Hazard for Any CVD Endpoint CARDS Placebo 189 events Atorvastatin 134 events Cumulative Hazard (%) Years Placebo 1410 1334 1275 992 621 287 Atorva 1428 1372 1337 1040 663 306

  19. 5 p<0.0001 Hazard ratio 1 12% decrease per 10 mm Hg decrement in BP 0 . 5 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0 1 6 0 1 7 0 Updated mean systolic blood pressure UKPDS 36. BMJ 2000; 321: 412-19 All Cause Mortality

  20. HOT: Events in relation to target blood pressure. Diabetic patients

  21. 5 p<0.0001 Hazard ratio 1 14% decrease per 1% decrement in HbA1c 0 . 5 0 5 6 7 8 9 1 0 1 1 Updated mean HbA1c UKPDS 35. BMJ 2000; 321: 405-12 All Cause Mortality

  22. Cardiovascular Disease Prevention • Improved cardiovascular risk with: • Improved glycaemic control (Metformin) • Improved BP control (Target < 140/80) • Addition of long acting ACEI if high risk • Lipid reduction • All secondary preventative measures • Aspirin, B Blocker

  23. Microvascular Complications • Diabetic Retinopathy • Diabetic Nephropathy • Microalbuminuria • Macroalbuminuria • Renal impairment • Diabetic Neuropathy • Sensory - Ulceration, Neuroarthropathy • Motor – Foot deformity • Autonomic – GI upset, Hypotension, ED

  24. Diabetic Eye Disease • Diabetic eye complications major cause of visual loss. • Most important preventable cause of blindness in Europe. • Accounts for about 90 % of blindness in diabetic patients. • St. Vincent Declaration 5 year targets 1989 • Incidence of blindness due to diabetes should be reduced by one third or more. • Duration of diabetes is the most important predictor.

  25. Prevalence of Retinopathy • In young persons with duration less than 5 yrs rare • In patients > 30 yrs with duration 5 yrs 20 % • Duration 10 yrs 40-50 % • Duration 20 yrs 90 % • Approx 30% of diabetic population have DR • Prevalence of visual impairment in UK ? 2-5 %?

  26. Diabetic Retinopathy • Approx 10-15 % of patients progress to sight threatening retinopathy • Pre proliferative retinopathy • Proliferative retinopathy • Vitreous haemorrhage • Maculopathy • Other sight threatening disease more common in diabetes • Cataract • Macular Degeneration • Glaucoma

  27. Risk Factors for Diabetic Retinopathy • duration of diabetes • poor glycaemic control • raised blood pressure • increasing number of microaneurysms • microalbuminuria and proteinuria (nephropathy) • raised triglycerides and lowered haematocrit • pregnancy

  28. Modifiable Risk Factors for Prevention of DR • Glycaemic Control • 1.7 % reduction in HbA1c (8.9% vs 7.2%) • 76 % risk reduction for developing DR • 43 % risk reduction for retinopathy progression • Blood Pressure Control • Smoking

  29. Evidence For Good Control • 1993 DCCT HbA1c 8.9 vs. 7.2 % • Reduced risk of developing: • Retinopathy 76 % • Microalbuminuria 39 % • Clinical neuropathy 60 % • 1998 UKPDS HbA1c 7.9 vs. 7.0 % • Reduced risk of: • Retinopathy 21% • Microalbuminuria 33% • Myocardial Infarction 16 %

  30. UKPDS Blood Pressure Control Study in 1148 Type 2 diabetic patients a tight blood pressure control policy which achieved blood pressure of 144 / 82 mmHg (vs 154/87) gave reduced risk for any diabetes-related endpoint 24% p=0.0046 diabetes-related deaths 32% p=0.019 stroke 44% p=0.013 heart failure 56% p=0.0043 microvascular disease 37% p=0.0092 retinopathy progression 34% p=0.0038 deterioration of vision 47% p=0.0036

  31. 1 5 p<0.0001 1 0 Hazard ratio 1 37% decrease per 1% decrement in HbA1c 0 . 5 0 5 6 7 8 9 1 0 1 1 Updated mean HbA1c UKPDS 35. BMJ 2000; 321: 405-12 Microvascular Endpoints

  32. Sight Threatening Retinopathy • No visual symptoms when most amenable to treatment • If visual symptoms present then prognosis poorer • Potocoagulation will abolish new vessels in 80 % and prevent blindness in >50% after 10 years • Photocoagulation will salvage vision in 50-60 % • Vitrectomy may be effective in restoring meaningful vision > 6/36

  33. Detection of Diabetic Retinopathy • Retinopathy is detected in its earliest and most treatable form only by clinical examination of eyes. • Ideally suited to screening programs • Screening must be comprehensive, of high sensitivity (>80%) and specificity (>95%). Should include measurement of visual acuity. Clear line of referral. • Various options:

  34. Performance of screening Sensitivity Specificity • General Practitioners 41 89 • Hospital Physician 67 96 • Non Mydriatic Camera 67 98 • Diabetologist 70 97 • Ophthalmology registrar 75 97 • 2 Field retinal photographs 89 86 • Combined 5 field + direct 97 95

  35. Patients with retinopathy • Aim for • Good glycaemic control HbA1c < 7.0% • Good BP control <130/70 • Lipid control / Statin Cholesterol <4.0 • Stop smoking • Correct anaemia

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