P H Scanlon

Gloucestershire Hospitals NHS Foundation Trust, Gloucester, England, United Kingdom

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Publications (41)175.71 Total impact

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    ABSTRACT: Aims: We aimed to use longitudinal data from an established screening programme with good quality assurance and quality control procedures and a stable well-trained workforce to determine the accuracy of grading in diabetic retinopathy screening. Methods: We used a continuous time-hidden Markov model with five states to estimate the probability of true progression or regression of retinopathy and the conditional probability of an observed grade given the true grade (misclassification). The true stage of retinopathy was modelled as a function of the duration of diabetes and HbA1c . Results: The modelling dataset consisted of 65 839 grades from 14 187 people. The median number [interquartile range (IQR)] of examinations was 5 (3, 6) and the median (IQR) interval between examinations was 1.04 (0.99, 1.17) years. In total, 14 227 grades (21.6%) were estimated as being misclassified, 10 592 (16.1%) represented over-grading and 3635 (5.5%) represented under-grading. There were 1935 (2.9%) misclassified referrals, 1305 were false-positive results (2.2%) and 630 were false-negative results (11.0%). Misclassification of background diabetic retinopathy as no detectable retinopathy was common (3.4% of all grades) but rarely preceded referable maculopathy or retinopathy. Conclusion: Misclassification between lower grades of retinopathy is not uncommon but is unlikely to lead to significant delays in referring people for sight-threatening retinopathy. This article is protected by copyright. All rights reserved.
    No preview · Article · Dec 2015 · Diabetic Medicine
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    Preview · Article · Dec 2015 · Diabetes Care
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    ABSTRACT: To report on the relationships between age at diagnosis of diabetes, time from registration with the screening programme to first diabetic eye screening and severity of diabetic retinopathy. Data were extracted from four English screening programmes and from the Scottish, Welsh and Northern Irish programmes. Time from diagnosis of diabetes to first screening and age at diagnosis were calculated. Time from registration with the screening programme to first screening episode is strongly related to age at registration. Within 18 months of registration 89% of 3958 young people under 18 years of age and 81% of 391 293 people over 35 years of age were seen. In 19 058 people between 18 and 34 years of age, 80% coverage was not reached until 2 years and 9 months. The time from diagnosis of diabetes to first screening is positively associated with severity of disease (P < 0.0001). This report is the first that to demonstrate that those in the 18-34 year age group are least likely to attend promptly for screening after registration with a higher risk of referable diabetic retinopathy being present at the time of first screen. Date of diagnosis should be recorded and prodigious efforts made to screen all people promptly after diagnosis. Screening programmes should collect data on those who have not attended within one year of registration. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    No preview · Article · Sep 2015 · Diabetic Medicine
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    ABSTRACT: Background: The English NHS Diabetic Eye Screening Programme was established in 2003. Eligible people are invited annually for digital retinal photography screening. Those found to have potentially sight-threatening diabetic retinopathy (STDR) are referred to surveillance clinics or to Hospital Eye Services. Objectives: To determine whether personalised screening intervals are cost-effective. Design: Risk factors were identified in Gloucestershire, UK using survival modelling. A probabilistic decision hidden (unobserved) Markov model with a misgrading matrix was developed. This informed estimation of lifetime costs and quality-adjusted life-years (QALYs) in patients without STDR. Two personalised risk stratification models were employed: two screening episodes (SEs) (low, medium or high risk) or one SE with clinical information (low, medium–low, medium–high or high risk). The risk factor models were validated in other populations. Setting: Gloucestershire, Nottinghamshire, South London and East Anglia (all UK). Participants: People with diabetes in Gloucestershire with risk stratification model validation using data from Nottinghamshire, South London and East Anglia. Main outcome measures: Personalised risk-based algorithm for screening interval; cost-effectiveness of different screening intervals. Results: Data were obtained in Gloucestershire from 12,790 people with diabetes with known risk factors to derive the risk estimation models, from 15,877 people to inform the uptake of screening and from 17,043 people to inform the health-care resource-usage costs. Two stratification models were developed: one using only results from previous screening events and one using previous screening and some commonly available GP data. Both models were capable of differentiating groups at low and high risk of development of STDR. The rate of progression to STDR was 5 per 1000 person-years (PYs) in the lowest decile of risk and 75 per 1000 PYs in the highest decile. In the absence of personalised risk stratification, the most cost-effective screening interval was to screen all patients every 3 years, with a 46% probability of this being cost-effective at a £30,000 per QALY threshold. Using either risk stratification models, screening patients at low risk every 5 years was the most cost-effective option, with a probability of 99-100% at a £30,000 per QALY threshold. For the medium-risk groups screening every 3 years had a probability of 43 –48% while screening high-risk groups every 2 years was cost-effective with a probability of 55–59%. Conclusions: The study found that annual screening of all patients for STDR was not cost-effective. Screening this entire cohort every 3 years was most likely to be cost-effective. When personalised intervals are applied, screening those in our low-risk groups every 5 years was found to be cost-effective. Screening high-risk groups every 2 years further improved the cost-effectiveness of the programme. There was considerable uncertainty in the estimated incremental costs and in the incremental QALYs, particularly with regard to implications of an increasing proportion of maculopathy cases receiving intravitreal injection rather than laser treatment. Future work should focus on improving the understanding of risk, validating in further populations and investigating quality issues in imaging and assessment including the potential for automated image grading.
    Full-text · Article · Sep 2015 · Health technology assessment (Winchester, England)
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    ABSTRACT: This study aimed to follow the natural progression of retinal changes in patients with diabetes. Such information should inform decisions with regard to the screening intervals for such patients. An observational study was undertaken linking the data from seven diabetes retinal screening programs across the U.K. for retinal grading results between 2005 and 2012. Patients with absent or background retinopathy were followed up for progression to the end points referable retinopathy and treatable retinopathy (proliferative retinopathy). In total 354,549 patients were observed for up to 4 years during which 16,196 patients progressed to referable retinopathy. Of patients with no retinopathy in either eye for two successive screening episodes at least 12 months apart, the conditions of between 0.3% (95% CI 0.3-0.8%) and 1.3% (1.0-1.6%) of patients progressed to referable retinopathy, and rates of treatable eye disease were <0.3% at 2 years. The corresponding progression rates for patients with bilateral background retinopathy in successive screening episodes were 13-29% and up to 4%, respectively, in the different programs. It may be possible to stratify patients for risk, according to baseline retinal criteria, into groups with low and high risk of their conditions progressing to proliferative retinopathy. Screening intervals for such diverse groups of patients could safely be modified according to their risk. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
    No preview · Article · Dec 2014 · Diabetes Care
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    ABSTRACT: Objective To examine the experiences of patients, health professionals and screeners; their interactions with and understandings of diabetic retinopathy screening (DRS); and how these influence uptake. Design Purposive, qualitative design using multiperspectival, semistructured interviews and thematic analysis. Setting Three UK Screening Programme regions with different service-delivery modes, minority ethnic and deprivation levels across rural, urban and inner-city areas, in general practitioner practices and patients’ homes. Participants 62 including 38 patients (22 regular-screening attenders, 16 non-regular attenders) and 24 professionals (15 primary care professionals and 9 screeners). Results Antecedents to attendance included knowledge about diabetic retinopathy and screening; antecedents to non-attendance included psychological, pragmatic and social factors. Confusion between photographs taken at routine eye tests and DRS photographs was identified. The differing regional invitation methods and screening locations were discussed, with convenience and transport safety being over-riding considerations for patients. Some patients mentioned significant pain and visual disturbance from mydriasis drops as a deterrent to attendance. Conclusions In this, the first study to consider multiperspectival experiential accounts, we identified that proactive coordination of care involving patients, primary care and screening programmes, prior to, during and after screening is required. Multiple factors, prior to, during and after screening, are involved in the attendance and non-attendance for DRS. Further research is needed to establish whether patient self-management educational interventions and the pharmacological reformulation of shorter acting mydriasis drops, may improve uptake of DRS. This might, in turn, reduce preventable vision loss and its associated costs to individuals and their families, and to health and social care providers, reducing current inequalities.
    Full-text · Article · Dec 2014 · BMJ Open
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    Peter H. Scanlon
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    ABSTRACT: Diabetic retinopathy is the leading cause of blindness in the working-age population in many countries. Despite the available treatments, some patients present late in the course of the disease when treatment is more difficult. If diabetic retinopathy is detected, tightening of modifiable risk factors (e.g. blood glucose and blood pressure) can slow disease progression. When sight-threatening retinopathy is detected, laser treatment and treatment with vascular endothelial growth factor (VEGF) inhibitors reduces the risk of visual loss.
    Preview · Article · Nov 2014 · Medicine
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    S J Aldington · I M Stratton · P H Scanlon

    Full-text · Poster · Sep 2014
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    P. H. Scanlon · j. Loftus · c. Starita · i. M. Stratton
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    ABSTRACT: AimsTo examine the relationship between visual acuity in each eye and Quality of Life (QoL) outcomes in people with diabetic macular oedema.Methods Cross sectional retrospective analysis of data collected at baseline in 289 people entered into a randomized clinical trial with diabetic macular oedema which investigated the safety and efficacy of a vascular endothelial growth factor inhibitor, pegaptanib sodium. At the baseline visit, visual acuity was measured through refraction and using retro-illuminated modified Early Treatment Diabetic Retinopathy Study Log MAR charts, and patient health-related QoL was determined using the European Quality of Life EQ–5D–3L and the Visual Functioning Questionnaire–25 (NEI–VFQ 25). A regression analysis with QoL score from each vision-related domain as the dependent variable was fitted using linear and quadratic terms of the better and worse eye, age, gender, adjusted for number of concurrent conditions, ethnicity and level of diabetes control.ResultsFor all vision-related QoL domains from NEI–VFQ 25 and EQ–5D–3L except ocular pain, both visual acuity in the better-seeing and the worse-seeing eye gave a significant increase in correlation coefficient over that obtained from clinical and demographic data. The NEI–VFQ 25 correlation was most closely associated with a weighted visual acuity measure of 0.75 in the better and 0.25 in the worse eye or 0.60 in the better and 0.40 in the worse eye.Conclusions We recommend that a weighted visual acuity measure from both eyes is considered in future diabetic macular oedema trials.This article is protected by copyright. All rights reserved.
    Full-text · Article · Sep 2014 · Diabetic Medicine

  • No preview · Article · Sep 2014 · Diabetologia
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    ABSTRACT: Background The NHS Diabetic Eye Screening Programme aims to reduce the risk of sight loss among people with diabetes in England by enabling prompt diagnosis of sight-threatening retinopathy. However, the rate of screening uptake between practices can vary from 55% to 95%. Existing research focuses on the impact of patient demographics but little is known about GP practice-related factors that can make a difference. Aim To identify factors contributing to high or low patient uptake of retinopathy screening. Design and setting Qualitative case-based study; nine purposively selected GP practices (deprived/ affluent; high/ low screening uptake) in three retinopathy screening programme areas. Methods Semi-structured interviews were conducted with patients, primary care professionals, and screeners. A comparative case-based analysis was carried out to identify factors related to high or low screening uptake. Results Eight possible factors that influenced uptake were identified. Five modifiable factors related to service and staff interactions: communication with screening services; contacting patients; integration of screening with other care; focus on the newly diagnosed; and perception of nonattenders. Three factors were non-modifiable challenges related to practice location: level of deprivation; diversity of ethnicities and languages; and transport and access. All practices adopted strategies to improve uptake, but the presence of two or more major barriers made it very hard for practices to achieve higher uptake levels. Conclusions A range of service-level opportunities to improve screening attendance were identified that are available to practices and screening teams. More research is needed into the complex interfaces of care that make up retinopathy screening.
    Full-text · Article · Aug 2014 · British Journal of General Practice
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    ABSTRACT: Risk perception of diabetic retinopathy among people with type 2 diabetes Authors Al-Athamneh, N.; Sturt, J.; Dolan, A.; Lindenmeyer, A. ; Stratton, I.M. ; Scanlon, P.H. Aim To explore how the risk of Diabetic Retinopathy (DR) is understood by people with diabetes and Health Care Professionals (HCPs). Methods A qualitative study was conducted using semi-structured interviews with a convenience sample of 25 participants. Of these, 20 participants were diagnosed with type 2 diabetes (11 White British and 9 South Asians), and 2 primary care physicians, 2 ophthalmologists, and 1 retinal screener. Participants were purposely recruited to fall into 5 groups of 5 participants each. 1) No DR; 2): background DR; 3) preproliferative DR; 4) proliferative DR; 5) HCPs. Risk information about DR was routinely provided to participants by HCPs after annual diabetic screening. Results Participants with diabetes were unfamiliar with the term retinopathy, however they were aware that diabetes could lead to changes in their sight or to Sight Threatening Diabetic Retinopathy (STDR).They were unaware that these changes could lead to permanent vision loss. Participants were optimistic about their chance of developing STDR. They perceived the seriousness of risk based on noticeable symptoms and scores of visual acuity rather than grade of retinopathy. Knowledge of risk was even less with the symptomless participants. There was a huge difference in the risk perception between participants and HCPs; when HCPs communicated risk message as high risk of developing STDR (such as: the chance of developing STDR is 10 in 100 or 10%), participants perceived it as low or very low risk. Conclusion Risk information should be personalised, and provided in a clear and attractive style based on level of understanding, particularly to the symptomless participants. HCPs should assess patients’ knowledge and understanding of risk when risk message is given. Risk communication tools could benefit participants to understand their own risk of developing DR, and reduces anxiety level. More quantitative study should target the effectiveness of risk tools.
    Full-text · Conference Paper · May 2014

  • No preview · Article · Mar 2014 · Diabetic Medicine
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    Full-text · Article · Jan 2014 · British Journal of General Practice
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    ABSTRACT: Purpose: To examine the level of agreement and reasons for disagreement between grading of diabetic retinopathy and maculopathy using mydriatic digital photographs in a diabetic retinopathy screening service (DRSS) and hospital eye service (HES). Methods: English NHS Diabetic Eye Screening Programme grades for diabetic retinopathy prospectively recorded on a hospital electronic medical record were compared to the grades from the DRSS event that prompted referral. In cases of disagreement, images were reviewed. Results: Data for 1,501 patients (3,002 eyes) referred between 2008 and 2011 were analyzed. The HES retinopathy grades were R0 (no retinopathy) in 341 eyes, R1 (background retinopathy) in 1,712 eyes, R2 (pre-proliferative retinopathy) in 821 eyes, and R3 (proliferative retinopathy) in 128 eyes. The DRSS grades were in agreement in 2,309 eyes (76.9%), recorded a lower grade in 227 eyes, and recorded a higher grade in 466 eyes. Agreement was substantial (κ = 0.65). The commonest cause for disagreement was overgrading of R1 as R2 by hospital clinicians. The HES maculopathy grades were M0 (no maculopathy) in 2,267 eyes and M1 (maculopathy) in 735 eyes. The DRSS were in agreement in 2,111 eyes (70.2%), recorded a lower grade in 106 eyes, and recorded a higher grade in 785 eyes. Agreement was fair (κ = 0.39). The commonest cause for disagreement was hospital clinicians missing fine exudates. Conclusions: This study establishes a benchmark standard for agreement between HES and DRSS grading. Review of DRSS and grading reports images for newly referred patients is likely to improve levels of agreement, particularly for diabetic retinopathy, and should be strongly encouraged.
    No preview · Article · Dec 2013 · European journal of ophthalmology
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    Peter H Scanlon · Stephen J Aldington · Irene M Stratton
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    ABSTRACT: There is currently an epidemic of diabetes in the world, principally type 2 diabetes that is linked to changing lifestyle, obesity, and increasing age of the population. Latest estimates from the International Diabetes Federation (IDF) forecasts a rise from 366 million people worldwide to 552 million by 2030. Type 1 diabetes is more common in the Northern hemisphere with the highest rates in Finland and there is evidence of a rise in some central European countries, particularly in the younger children under 5 years of age. Modifiable risk factors for progression of diabetic retinopathy (DR) are blood glucose, blood pressure, serum lipids, and smoking. Nonmodifiable risk factors are duration, age, genetic predisposition, and ethnicity. Other risk factors are pregnancy, microaneurysm count in an eye, microaneurysm formation rate, and the presence of any DR in the second eye. DR, macular edema (ME), and proliferative DR (PDR) develop with increased duration of diabetes and the rates are dependent on the above risk factors. In one study of type 1 diabetes, the median individual risk for the development of early retinal changes was 9.1 years of diabetes duration. Another study reported the 25 year incidence of proliferative retinopathy among population-based cohort of type 1 patients with diabetes was 42.9%. In recent years, people with diabetes have lower rates of progression than historically to PDR and severe visual loss, which may reflect better control of glucose, blood pressure, and serum lipids, and earlier diagnosis.
    Full-text · Article · Oct 2013 · Middle East African journal of ophthalmology
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    ABSTRACT: AimsTo report estimates of the prevalence of diabetic retinopathy (DR) and maculopathy grades for a large cohort of patients managed by the UK hospital eye service (HES).Methods Anonymised data were extracted from 30 UK NHS hospital trusts using a single ophthalmic electronic medical record (EMR) for the period from April 2000 to November 2010 to create the National Ophthalmology Database (NOD). From 2007, the EMR facilitated capture of a nationally agreed-upon standardised data set (DR Structured Assessment) relating to the presence or absence of clinical signs of DR and maculopathy. An algorithm in the software automatically calculated the Early Treatment of Diabetic Retinopathy Study grades of retinopathy and maculopathy.ResultsBetween 2007 and 2010, 307 538 patients had data on the NOD, with 76 127 (24.8%) patients having been recorded as having diabetes. The proportion of patients with diabetes who had a structured assessment increased from 50.7% (2007) to 86.8% (2010). In each NHS year, 12.6-20.6% of eyes with structured assessments had no DR; 59.6-67.3% had non-proliferative DR; and 18.3-20.9% had active or regressed proliferative DR. Clinically significant macular oedema was present in 15.8-18.1% of eyes, and in 8.7-10.0% of eyes, this involved the central macula.Conclusion This study provides contemporary estimates of the prevalence of retinopathy and maculopathy grades in a large cohort of patients with diabetes managed by the UK HES. Centre-involving diabetic macular oedema, potentially amenable to anti-VEGF therapy, is present in the eyes of almost 10% of these patients. This information is useful for clinicians, health-care economists, and commissioners involved in planning and delivering diabetic eye services.Eye advance online publication, 20 September 2013; (2013) 0, 000-000. doi:10.1038/eye.2013.196.
    Full-text · Article · Sep 2013 · Eye (London, England)
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    P H Scanlon · S J Aldington · I M Stratton
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    ABSTRACT: To assess whether there is a relationship between delay in retinopathy screening after diagnosis of Type 2 diabetes and level of retinopathy detected. Patients were referred from 88 primary care practices to an English National Health Service diabetic eye screening programme. Data for screened patients were extracted from the primary care databases using semi-automated data collection algorithms supplemented by validation processes. The programme uses two-field mydriatic digital photographs graded by a quality assured team. Data were available for 8183 screened patients with diabetes newly diagnosed in 2005, 2006 or 2007. Only 163 with Type 1 diabetes were identified and were insufficient for analysis. Data were available for 8020 with newly diagnosed Type 2 diabetes. Of these, 3569 were screened within 6 months, 2361 between 6 and 11 months, 1058 between 12 and 17 months, 366 between 18 and 23 months, 428 between 24 and 35 months, and 238 at 3 years or more after diagnosis. There were 5416 (67.5%) graded with no retinopathy, 1629 (20.3%) with background retinopathy in one eye, 753 (9.4%) with background retinopathy in both eyes and 222 (2.8%) had referable diabetic retinopathy. There was a significant trend (P = 0.0004) relating time from diagnosis to screening detecting worsening retinopathy. Of those screened within 6 months of diagnosis, 2.3% had referable retinopathy and, 3 years or more after diagnosis, 4.2% had referable retinopathy. The rate of detection of referable diabetic retinopathy is elevated in those who were not screened promptly after diagnosis of Type 2 diabetes. This article is protected by copyright. All rights reserved.
    Full-text · Article · Sep 2013 · Diabetic Medicine

  • No preview · Conference Paper · Sep 2013
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    ABSTRACT: Title: The influence risk communication tools on diabetes self management Authors: Al-Athamneh N, Sturt J, Stratton IM, Lindenmeyer A, Scanlon PH. Aims 1. To explore the effect of different ways of communicating risk information about DR to people with diabetes 2. To explore the possible use of risk communication tools to improve diabetes self management. Methods A qualitative study was conducted using semi-structured interviews with a convenience sample of 25 participants. Of these, 20 participants were diagnosed with type 2 diabetes (11 White British and 9 South Asians), and 5 participants who were health care professionals (HCPs): (3 White British and 2 South Asians). HCPs were 2 GPs, an ophthalmologist, and 2 retinal screeners. Participants were purposively recruited from primary and secondary care trusts to fall into 5 groups of 5 participants each. 1) No DR (R0) 2): background DR (R1); 3) preproliferative DR (R2); 4) proliferative DR (R3); 5) HCPs. Risk communication tools were identified from different clinical settings e.g cancer screening, modified and presented to the participants. Results Providing individualised risk information in a clear and attractive style improved patients’ understanding of their own risk and therefore may also improve diabetes self management. The use of visual aids was found to facilitate the presentation of risk for those who could not read, or whose their first language was not English. Participants were able to score themselves as high or low risk, a feature which was welcomed by patients, as they liked the idea of assessing their own risk. Conclusion Visual tools may be useful in communicating the risk of DR to people with diabetes. Continuing work will now modify, evaluate, and improve a risk tool to communicate risk information about DR to people with diabetes.
    Full-text · Conference Paper · May 2013