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 = 2.1 %
Forth Valley = 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. Osmotic Symptoms & Fatigue Weight loss / gain Infection
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 = IFG
2 hr post 75g glucose = IGT
2 hr post 75g glucose > = DM

8. 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

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 % of patients each year
Coma occurs in ~ 10 % of patients each year 33

13. 34

14. Causes of hypoglycaemia
Management Errors
Inadequate Carbohydrate
Altered Kinetics
Lipohypertrophy, Site massage, Heat, Cold, Antibodies, Renal, Exercise, Human insulin
Increased Sensitivity
Addison’s disease, Hypothyroidism, Hypopituitarism, Changes in gonadal steroids, Pregnancy
Factitious

15. 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 36

16. Morbidity of hypoglycaemia
CNS Coma and Convulsions Transient motor deficits Permanent brain damage Cerebral Oedema
CVS Arrhythmia Myocardial ischaemia Stroke
Fractures, Vitreous haemorrhage 37

17. Treatment of hypoglycaemia
Treated immediately by oral glucose 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. 38

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

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

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

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

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

23. 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

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

25. 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.

26. 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 %
Duration 20 yrs %
Approx 30% of diabetic population have DR
Prevalence of visual impairment in UK ? %?

27. Diabetic Retinopathy
Approx % 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

28. 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

29. 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

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

31. 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

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

33. 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 %
Vitrectomy may be effective in restoring meaningful vision > 6/36

34. 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:

35. Performance of screening
Sensitivity Specificity
General Practitioners
Hospital Physician
Non Mydriatic Camera
Diabetologist
Ophthalmology registrar
2 Field retinal photographs
Combined 5 field + direct

36. 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