Incidence of diabetic retinopathy in people with type 2 diabetes mellitus attending the Diabetic Retinopathy Screening Service for Wales: retrospective analysis.

OBJECTIVES: To determine the incidence of any and referable diabetic retinopathy in people with type 2 diabetes mellitus attending an annual screening service for retinopathy and whose first screening episode indicated no evidence of retinopathy. DESIGN: Retrospective four year analysis. SETTING: Screenings at the community based Diabetic Retinopathy Screening Service for Wales, United Kingdom. PARTICIPANTS: 57,199 people with type 2 diabetes mellitus, who were diagnosed at age 30 years or older and who had no evidence of diabetic retinopathy at their first screening event between 2005 and 2009. 49,763 (87%) had at least one further screening event within the study period and were included in the analysis. MAIN OUTCOME MEASURES: Annual incidence and cumulative incidence after four years of any and referable diabetic retinopathy. Relations between available putative risk factors and the onset and progression of retinopathy. RESULTS: Cumulative incidence of any and referable retinopathy at four years was 360.27 and 11.64 per 1000 people, respectively. From the first to fourth year, the annual incidence of any retinopathy fell from 124.94 to 66.59 per 1000 people, compared with referable retinopathy, which increased slightly from 2.02 to 3.54 per 1000 people. Incidence of referable retinopathy was independently associated with known duration of diabetes, age at diagnosis, and use of insulin treatment. For participants needing insulin treatment with a duration of diabetes of 10 years or more, cumulative incidence of referable retinopathy at one and four years was 9.61 and 30.99 per 1000 people, respectively. CONCLUSIONS: Our analysis supports the extension of the screening interval for people with type 2 diabetes mellitus beyond the currently recommended 12 months, with the possible exception of those with diabetes duration of 10 years or more and on insulin treatment.

Screening for diabetic retinopathy by general practitioners: ophthalmoscopy or retinal photography as 35 mm colour transparencies?

In order to assess the relative ability of general practitioners (GPs) to detect diabetic retinopathy (DR), especially sight-threatening diabetic retinopathy (STDR) by direct ophthalmoscopy or by examining, on a separate occasion, retinal images as 35 mm colour transparencies, a South and Mid Wales primary care-based study was performed in four general practices (six GPs). The participating GPs were provided with standardized training and equipment. Both methods were compared to the 'reference' grade of DR provided by the Diabetic Retinopathy Reading Centre (London), based on the same retinal images. Ophthalmoscopy and retinal photography (Canon CR4 45NM) with mydriasis were all practice based. The clinical assessments were based on a protocol developed for screening for DR in Europe. A total of 996 people with diabetes were identified, representing a prevalence of known diabetes of 2.1%. After exclusions on medical grounds, 897 patients were available for screening, of whom 605 (68%) were photographed. Based on the retinal images, the reference centre identified DR in 43% and STDR in 14.4%. In total, 597 valid comparisons between GPs and the reference centre were obtained; of these, 462 (77%) were high quality photographs which were used in subsequent analysis. The sensitivity for detecting any DR increased from 62.6% (95% CI 55.9-69.4) with ophthalmoscopy to 79.2% (95% CI 73.6-84.9) using retinal photographs, specificity remaining essentially unchanged at 75.0 (95% CI 69.5-80.5) and 73.5% (95% CI 68.0-79.1) with the positive predictive value (PPV) increasing from 67.2 (95% CI 60.4-74.0) to 71.0% (95% CI 65.0-77.0), respectively. The detection of STDR sensitivity increased from 65.7 (95% CI 54.4-77.1) with ophthalmoscopy alone to 87.3% (95% CI 79.4-95.2) based on retinal photographs with specificity falling from 93.8 (95% CI 91.4-96.3) to 84.8% (95% CI 81.2-88.5) and PPV from 65.7 (95% CI 54.4-77.1) to 51.2% (95% CI 42.1-60.3), respectively. We conclude that the use of standardized 35 mm colour transparency retinal photographs for screening by trained GPs in a primary care setting achieves an acceptable detection rate (>87%) for STDR, contrasting with ophthalmoscopy alone (66%), which was below the proposed UK standard of 80%.

Practical application of the European Field Guide in screening for diabetic retinopathy by using ophthalmoscopy and 35 mm retinal slides.

The Welsh Community Diabetic Retinopathy Study was designed to assess the effectiveness of the Field Guide Book for screening for diabetic retinopathy in Europe. A community-based sample (prevalence 2%) of diabetic patients was recruited from four general practices. Standardised training and equipment were provided. All patients were invited to attend practice-based screening sessions on two occasions over 3 years (phases 1 and 2). After mydriasis, clinical ophthalmoscopy was performed by a study optometrist and general practitioners (GPs). 2 x 45 field 35 mm retinal slides were obtained according to EURODIAB protocol. Anonymised slides were assessed by GPs, diabetologists and the optometrist. All the findings were graded externally (reference standard). In phase 2 community optometrists also performed ophthalmoscopy and assessed photographs. For detecting sight threatening diabetic retinopathy using ophthalmoscopy, GPs achieved a sensitivity of 65.7%, specificity 93.8% and positive predictive value (PPV) 65.7%. Community optometrists achieved a sensitivity of 82.2% with a PPV of 50.7%; the study optometrist 79.2 and 55.9%, respectively. The use of 35 mm slides improved sensitivity for the detection of sight threatening retinopathy to 87.3, 91.1 and 97.2% for GPs, community optometrists and the study optometrist, respectively. PPV fell to 51.2% for GPs, 40.6% for community optometrists, but increased to 58.8% for the study optometrist. Diabetologists achieved a sensitivity of 88.7% and a PPV of 65.6%. It is concluded that the European field guide is an effective tool for screening for retinopathy in clinical practice.

Effectiveness of programme for reducing cardiovascular risk for men in one general practice.

OBJECTIVES: To assess the effectiveness of a programme for reducing cardiovascular risk in men in terms of clinical measurements and perceptions of patients. DESIGN: Collection of paired data on men attending well person clinics over three to five years. Questionnaire to determine changes in risk related habits. SETTING: Well person clinics in rural general practice with five partners in mid-Wales. SUBJECTS: The first 687 men seen in the clinic: analysable data obtained on 520. Initial age range 28-60 years. MAIN OUTCOME MEASURES: Analysis of serum cholesterol concentration (mmol/l) and blood pressure (mm Hg). Changes in diet, exercise, smoking, and drinking. RESULTS: Mean (SD) cholesterol concentration for all subjects increased from 5.8 (1.0) to 6.0 (1.0), p < 0.001. Overall percentage of ideal weight and mean systolic blood pressure also increased. Mean diastolic blood pressure was unchanged at 84 mm Hg. Professed dietary change, age, and number of visits all had significant effects on final cholesterol concentration. Those seen more often showed a significant decrease in cholesterol concentrations (in those seen more than twice mean (SD) initial value 6.7 (0.9) mmol/l v final value 6.5 (1.0) mmol/l, p < 0.001). Those over 45 years at start of study showed a significant decrease in diastolic blood pressure (mean (SD) initial value 89 (9) mm Hg v final value 86 (7) mm Hg, p < 0.001). CONCLUSIONS: These clinics are not effective in achieving a reduction in mean cholesterol concentration or blood pressure, despite evidence that the message of reduction in risk had been successfully transmitted. Success was achieved in older patients and those in whom a definite problem was identified. Identification of high risk groups and clinical case finding with appropriate long term follow up may be more cost effective in reducing cardiovascular risk than non-specific screening of the whole population.

Characteristics and pattern of care of a diabetic population in mid-Wales.

The pattern of care and demographic features of diabetes in a largely rural Welsh population were investigated before the introduction of measures to improve diabetic care. All data were obtained from general practice notes. Of the population studied 1.01% were identified as diabetic. There were no demographic differences from recently published English studies. Seventy per cent of the diabetic patients had not seen a consultant within the preceding year. The level of surveillance for biochemical control and complications of diabetes was better in those who had had recent consultant care. However, basic surveillance data was missing in many consultant letters to general practitioners. The prevalence of known serious diabetic eye disease (9%) in the study population was similar to that found in a recent study of a structured care system. Proposed improvements in diabetic care must take into account the large number of patients not attending hospital clinics. Communication between consultant clinics and general practitioners must be improved.