National diabetic Retinopathy Screening Programmes, Principles, Processes

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National diabetic Retinopathy Screening
Programmes, Principles, Processes Protocols

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

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Criteria for Screening

• The Condition
• The Test
• The Treatment
• The Screening Programme

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Nationally Managed Screening Programmes
Antenatal
Newborn
Adult

• Phenylketonuria
• Hypothyroidism
• Cystic Fibrosis
• Hearing Impairment
• Haemoglobinopathy

• Breast Cancer
• Cervical Cancer
• Diabetic Retinopathy
• Colorectal

• Downs Syndrome
• Cystic Fibrosis
• HIV

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Screening tests should be-

• Simple to apply.
• Cheap
• Easy to perform.
• Unambiguous to interpret.
• Identify those with disease and exclude those
  without.

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Effectiveness of Screening

• Reliable, sensitive and specific tests.
• Effective treatments
• Levels of uptake among target population.
• Compliance with treatment and the extent to which
  costs associated with screening are minimised so
  are not to outweigh benefits.

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Why screen for 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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Sight Threatening Retinopathy Treatment

• Most amenable to treatment when no visual
  symptoms
• 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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National Screening Programmes

• Cover a defined population.
• Have a simple set of objectives.
• Develop valid and reliable criteria to measure
  performance and produce an annual report.
• Relate performance to explicit quality standards.
• Organise quality assurance systems to help
  professionals and organisations prevent errors
  and improve performance.
• Communicate clearly and efficiently with all
  interested individuals and organisations.
• Co-ordinate the management of these activities,
  clarifying the responsibilities of all
  individuals and organisations involved.

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Principles and Values of Screening Programme

• Screening Programmes should offer adequate
  information to facilitate informed choice.
• Professionals involved in screening programmes
  need development and support.
• Screening Programmes aim to maximise benefit,
  minimise harm, and make the best use of the
  resources invested.
• Screening Programmes and Clinical Services should
  work together to provide a seamless experience if
  treatment is required.
• Programmes are committed to continuous
  improvement in performance and standards.
• Confidentiality must be maintained at all times,
  both in relation to the screening process and its
  results.

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Patient Issues

• individuals involved in this screening programme
  are unlike those involved in most other screening
  programmes
• already undergoing routine medical care for their
  condition
• patients of both sexes
• wide age range
• higher prevalence in some ethnic minorities

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Patient Issues

• mydriasis is an undesirable feature of screening
• Patient preferences for clear, timely information
  about all aspects of screening
• Fear created by delay in results
• Confidence in service
• Low false negative rate
• Low false positive rate
• Clear procedures for referral if positive

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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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Slit Lamp Examination

• Gold Standard
• Requires Midriasis
• Ophthalmologists
• Training
• Expensive
• Slow
• No permanent record.
• Difficult to QA

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Direct Ophthalmoscopy

• Easy
• Quick
• Cheap
• Requires midriasis
• Poor sensitivity 40-70
• No permanent record
• Difficult to QA

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Performance of screening

• Sensitivity Specificity
• General Practitioners 41 89
• Hospital Physician 67 96
• Diabetologist 70 97
• Ophthalmology registrar 75 97
• Digital photographytrained graders 88 95
• Combined 5 field direct 97 95

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Digital Retinal Photography

• Relatively easy with training
• Sensitive gt80
• Quick
• Possible without midriasis
• Permanent record
• Easy to QA

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Limitations of screening

• Technical
• Not all images are gradable
• Delay in image to result
• Second examinations
• False positive / negative results
• System
• Communication between Screening team /
  Ophthalmology
• Communication with patients
• Human
• Errors false negative
• Grading guidelines
• Training
• QA
• Process for review managing errors

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Retinal Screening Standards (QIS)

• Standard 1 Organisation
• Standard 2 Call-Recall and Failsafe
• Standard 3 Screening Process
• Standard 4 Proficiency Testing
• Standard 5 Referral

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Standard 1 Organisation

• Well-organised strategic planning group
• LDSAG / MCN / Retinal Screening Group
• Local strategy and implementation plan
• Agreed guidelines for effective communication
• Identified individual with delegated
  responsibility and authority for co-ordinating
  and monitoring
• Board Screening Coordinator
• Clinical Lead
• Service Management

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Service specification includes

• 1. audit
• 2. training
• 3. quality assurance
• 4. information for people with diabetes
• 5. call-recall
• 6. photography
• 7. grading
• 8. reporting
• 9. follow-up
• 10. treatment
• Arrangements to ensure that the specification is
  monitored and met

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Standard 2 Call-Recall Failsafe

• All eligible people have a written prompt to
  attend for screening at least once every year
• Accurate / validated Up to Date Diabetes Register
• Arrangements are in place for special cases
• Long term institutions
• Hospital patients
• A minimum of 80 of eligible people with diabetes
  are screened within 12 months
• Screening uptake is monitored at NHS Board level
• NSD protocol is followed for the management of
  non-attenders
• 3 attempts at communication
• All staff involved in call-recall receive
  training on IT systems

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Standard 2 Call-Recall Failsafe

• Non discriminatory
• Clear guidelines for exclusion
• Protocol defining failsafe procedures for
  follow-up of eligible people with diabetes with
  referable grades of retinopathy

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WHO CAN BE SUSPENDED?

• 1. Has made his or her own informed choice
• 2. Under the age of 12 years
• 3. Does not have perception of light vision
• 4. Terminally ill
• 5. Has a physical or mental disability preventing
  either screening or treatment
• 6. Currently under the care of an ophthalmologist
  for management of diabetic retinopathy.
• 7. Temporarily unavailable
• 8. Deceased.

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Follow up protocol

• After first ophthalmology examination
• Return to screening programme and re-call for
  screening in 12 months
• Return to the screening programme and re-call for
  screening in 6 months
• Continue under care of Ophthalmology for Diabetic
  Retinopathy. Patient suspended 12 months from DRS

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Follow up protocol failsafe

• If no record of Eye Clinc visit at expiry of
  suspension
• Contact ophthalmology care provider to confirm if
  still under retinopathy surveillance
• If confirmed suspend 12 months
• If no longer under surveillance either
• Ref back to ophthalmology GP or if discharged
• Suspend appropriate interval for later rebooking

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Standard 3 Screening Process

• Photographs are taken using equipment and
  techniques in accordance with national
  guidelines.
• All staff have full training in retinal screening
  before working unsupervised
• Staff undertake continuing professional
  development (CPD)
• A minimum of 80 of people screened are sent the
  result in writing within 4 weeks
• Training / Use of Midriatics
• MHRA for Tropicamide prescribing
• PGDs for other midriatics
• Avoidable technical failure
• Patient factors

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Standard 4 Proficiency Testing

• All grading staff have successfully completed a
  recognised training programme. (CG)
• Scottish Diabetic Retinopathy Grading Scheme 2007
  v1.0
• Level 1
• Level 2
• Level 3 (Currently Ophthalmologist)
• Slit Lamp Examiner
• Competency of individual graders assessed by
  ongoing quality assurance. (500 randomly selected
  patients)
• Clinically important grading errors further
  investigated and/or additional training of the
  grader is carried out.
• Screening history review of those developing
  referable retinopathy and audit is undertaken
• External quality assurance (EQA).

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Standard 5 Referral

• All eligible people with referable retinopathy,
  are referred to an ophthalmologist for assessment
  and treatment.
• Diabetes care provider should be notified of all
  people whose eye examination has revealed
  retinopathy

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Meeting Reporting Targets

• Ongoing Audit
• National agreed minimum data set
• 100 Eligible patients invited annually
• 80 Eligible population screened in 12 months
• Eligible population screened in 2 years
• Re-screen for Tech Failure
• Average time for report
• 80 receive result within 20 working days
• negative
• observable
• referable
• referable referred to ophthalmologist
• Average time to ophthalmologist
• graders with target 500 sets QA
• QA error rate (False neg, False pos, Poor Quality
  image)

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• Scottish Diabetes Retinopathy Screening
  Collaborative
• http//www.ndrs.scot.nhs.uk/index.htm