Presentation on theme: "Diabetes & Its Relevance to Retinopathy Screening Dr John Doig Consultant Diabetologist DRS Clinical Lead Forth Valley."— Presentation transcript:
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 Managing Risk Factors
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).
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 %
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
Diagnosis Symptoms –Osmotic Symptoms & Fatigue –Weight loss / gain –Infection –Neuropathic Symptoms –Visual Upset –Cardiovascular symptoms
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
Type of Diabetes 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
Other types of Diabetes Gestational Drug induced –Steroids, Atypical Neuroleptics Metabolic –Haemachromatosis, Cushings, Acromegaly Pancreatic disease MODY (Genetic) Stress hyperglycaemia
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
Causes of hypoglycaemia Management Errors Inadequate Carbohydrate Altered KineticsLipohypertrophy, Site massage, Heat, Cold, Antibodies, Renal, Exercise, Human insulin Increased SensitivityAddison’s disease, Hypothyroidism, Hypopituitarism, Changes in gonadal steroids, Pregnancy Factitious
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
Morbidity of hypoglycaemia CNSComa and Convulsions Transient motor deficits Permanent brain damage Cerebral Oedema CVSArrhythmia Myocardial ischaemia Stroke Fractures, Vitreous haemorrhage
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.
12% decrease per 10 mm Hg decrement in BP p<0.0001 0.5 1 5 110120130140150160170 All Cause Mortality Updated mean systolic blood pressure Hazard ratio UKPDS 36. BMJ 2000; 321: 412-19
HOT: Events in relation to target blood pressure. Diabetic patients
All Cause Mortality 14% decrease per 1% decrement in HbA1c p<0.0001 0.5 1 5 0567891011 Updated mean HbA 1c Hazard ratio UKPDS 35. BMJ 2000; 321: 405-12
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
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.
Prevalence of Retinopathy In young persons with duration less than 5 yrsrare In patients > 30 yrs with duration 5 yrs20 % Duration 10 yrs40-50 % Duration 20 yrs90 % Approx 30% of diabetic population have DR Prevalence of visual impairment in UK ? 2-5 %?
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
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
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
Evidence For Good Control 1993 DCCTHbA1c 8.9 vs. 7.2 % –Reduced risk of developing: Retinopathy 76 % Microalbuminuria 39 % Clinical neuropathy 60 % 1998 UKPDSHbA1c 7.9 vs. 7.0 % –Reduced risk of: Retinopathy 21% Microalbuminuria 33% Myocardial Infarction 16 %
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 endpoint24% p=0.0046 diabetes-related deaths32%p=0.019 stroke44%p=0.013 heart failure56%p=0.0043 microvascular disease37%p=0.0092 retinopathy progression34%p=0.0038 deterioration of vision47%p=0.0036 UKPDS Blood Pressure Control Study
Microvascular Endpoints 0.5 1 10 15 0567891011 37% decrease per 1% decrement in HbA1c p<0.0001 Updated mean HbA 1c Hazard ratio UKPDS 35. BMJ 2000; 321: 405-12
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
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:
Performance of screening SensitivitySpecificity General Practitioners4189 Hospital Physician6796 Non Mydriatic Camera6798 Diabetologist7097 Ophthalmology registrar7597 2 Field retinal photographs8986 Combined 5 field + direct9795
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