Diabetes

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Diabetes Its Relevance to Retinopathy Screening

• Dr John Doig
• Consultant Diabetologist
• DRS Clinical Lead Forth Valley

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Diabetes Its Relevance to Retinopathy Screening

• What is diabetes
• Diagnosis
• Types of Diabetes
• Treatment
• Complications
• Acute metabolic
• Macrovascular
• Microvascular
• Managing Risk Factors

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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).

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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

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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

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Diagnosis

• Symptoms
• Osmotic Symptoms Fatigue
• Weight loss / gain
• Infection
• Neuropathic Symptoms
• Visual Upset
• Cardiovascular symptoms

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Diagnosis Diagnostic Criteria

• Fasting Plasma Glucose gt7.0 (on 2 occasions)
• Random Plasma Glucose gt11.1 (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 gt 11.1 DM

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Type of Diabetes

• Type I
• Young lt 35
• Thin weight loss
• Rapid onset
• Ketonuria
• Autoimmune
• B Cell failure
• Insulin Dependent

• Type 2
• Older gt 35
• Overweight
• Onset months
• Strong FH
• Complications
• Insulin resistance
• Late B Cell failure
• Hyperinsulinaemia
• Metabolic syndrome
• Cardiovascular Disease

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Other types of Diabetes

• Gestational
• Drug induced
• Steroids, Atypical Neuroleptics
• Metabolic
• Haemachromatosis, Cushings, Acromegaly
• Pancreatic disease
• MODY (Genetic)
• Stress hyperglycaemia

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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

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Acute Metabolic Complications

• Diabetic Ketoacidosis
• Hyper Osmolor Nonketotic Coma
• Lactic Acidosis
• Hypoglycaemia

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Hypoglycaemia

• Common side effect of Insulin or Sulphonylureas
• Does not occur with Metformin, Acarbose or TZDs
• 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

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Causes of hypoglycaemia
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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

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Morbidity of hypoglycaemia

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

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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.

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Macrovascular Complications

• Coronary Artery Disease
• Peryipheral Vascular Disease
• Cerebro Vascular Disease
• Hyperlipidaemia
• Hypertension
• Obesity

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Cumulative Hazard for Any CVD Endpoint CARDS
Relative Risk -32 (95 CI -45, -15) p0.001
Placebo 189 events
Atorvastatin 134 events
Cumulative Hazard ()
Years
621
992
1275
1334
Placebo
1410
287
663
1040
1337
1372
Atorva
1428
306
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All Cause Mortality
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HOT Events in relation to target blood pressure.
Diabetic patients
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All Cause Mortality
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Cardiovascular Disease Prevention

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

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Microvascular Complications

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

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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.

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Prevalence of Retinopathy

• In young persons with duration less than 5
  yrs rare
• In patients gt 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 ?

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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

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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

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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

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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

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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 p0.0046
• diabetes-related deaths 32 p0.019
• stroke 44 p0.013
• heart failure 56 p0.0043
• microvascular disease 37 p0.0092
• retinopathy progression 34 p0.0038
• deterioration of vision 47 p0.0036

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Microvascular Endpoints
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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 gt50 after 10 years
• Photocoagulation will salvage vision in 50-60
• Vitrectomy may be effective in restoring
  meaningful vision gt 6/36

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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 (gt80) and specificity (gt95). Should
  include measurement of visual acuity. Clear line
  of referral.
• Various options

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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

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Patients with retinopathy

• Aim for
• Good glycaemic control HbA1c lt 7.0
• Good BP control lt130/70
• Lipid control / Statin Cholesterol lt4.0
• Stop smoking
• Correct anaemia