Table 5.
Characteristics of the relevant studies.
| First author, year | Region | Study subject | Newly diagnosed diabetes | Follow up period | Age (Mean ±SD, years) | Sex N (%) | Results/Conclusion |
|---|---|---|---|---|---|---|---|
| Liu et al. (7) | Taiwan | 795 | No | January 1990–December 1992 | 59.7 ± 8.32 | Female: 441 (55.5); Male: 354 (44.5) | 1. An annual screening program, a biennial screening regime and a 4-yearly screening regime can lead to 54% (95% CI: 44–62%), 51% (95% CI: 41–59%), and 46% (95% CI: 36–54%) reductions in blindness, respectively |
| Younis et al. (10) | United Kingdom | 4,770 | Yes, but number not specified | 6 years | (median [IQR]) NDR: 63.4 (56.1–69.8); Background DR: 64.7 (57.9–71.1); Mild preproliferative DR: 65.0 (57.6–71.8) | Female: 2,116 (44.4); Male: 2,654 (55.6) | 1. Yearly incidence of sight-threatening DR in patients without DR at baseline was 0.3% (95% CI 0.1–0.5) in the first year, rising to 1.8% (1.2–2.5) in the fifth year; cumulative incidence at 5 years was 3.9% (2.8–5.0) 2. Rates of progression to sight-threatening DR in year 1 by baseline status were: background 5.0% (3.5–6.5), and mild preproliferative 15% (10.2–19.8) 3. Mean screening intervals by baseline status were: no DR 5.4 years (95% CI 4.7–6.3), background 1.0 years (0.7–1.3), and mild preproliferative 0.3 years (0.2–0.5) |
| Agarwal et al. (28) | India | 301 | Yes (n = 128) | June 2003–September 2004 | Group I (Targeted Screening): 54 ± 11; Group II (Newly Diagnosed): 52 ± 12 | Female: 148 (49.2); Male: 153 (50.8) | 1. The occurrence of DR was 6.35% (95% CI, 2.5–9.5) in Group I and 11.71% (95% CI, 5.6–16.4) in Group II. (P > 0.05), including sight-threatening retinopathy, in rural versus urban population and in Group I versus Group II 2. Group II with systolic blood pressure (BP) >140 were more likely to have retinopathy (P = 0.02) |
| Namperu malsamy et al. (22) |
India | 25,969 | Yes (n = 1478) | August 2005–March 2006 | N/A | Female: 13,525 (52.1%); Male: 12,444 (47.9%) | 1. Among the subjects screened for DM, 2802 (10.8%, 95% CI 9.3–12.2%) were found to have DM 2. DR was detected in 298 (1.2%) of included subjects. The age-gender-adjusted prevalence of DR is 0.05% (95% CI 0.04–0.06%) for rural and 1.03% (95% CI 0.89 to 1.12%) for urban areas 3. The overall age–gender-cluster adjusted prevalence of DR was 0.74% (95% CI 0.66–0.83%). DR was present in 12.2% (95% CI 10.4 to 14.1%) of the DM population |
| Agardh et al. (9) | Sweden | 1,322 | Not specified | 3 years | 55 ± 12 | N/A | 1.73% were still without retinopathy after 3 years, and 28% had developed mild or moderate retinopathy, but none developed severe nonproliferative or proliferative retinopathy |
| Lee et al. (29) | China | 3,510 | Yes (n = 3510) | 2006–2009 | 59.5 | Female: 1,811 (51.6); Male: 1,699 (48.4) | 1. The prevalence of DR was 18.2% (639 patients) among the recently diagnosed DM patients 2. In 639 patients with DR, 7% were with significant macular edema |
| Wang et al. (30) | China | 368 | Yes (n = 247) | 2006–2007 | N/A | Female: 233 (63.3); Male: 135 (36.7) | 1. The age-standardized prevalence of DR was 43.1%. In multivariable-adjusted logistic regression models for all DM participants, independent risk factors for DR were longer duration of diabetes (OR = 3.07, 95% CI 1.94–4.85), higher FPG levels (OR 1.17; 95% CI: 1.08–1.27) and higher systolic BP (OR 1.22; 95% CI: 1.08–1.37) 2. For newly diagnosed diabetes, the only significant factor of DR was higher FPG levels (OR 1.17; 95% CI 1.05–1.29, per mmol/l increase) |
| Looker et al. (27) | United Kingdom | 51,526 | Yes (n = 51,526) | Jan. 2005–May 2008 | 61.8 ± 12.8 | Female: 22,950 (45); Male: 28,576 (55) | 1. The prevalence at first screening of any retinopathy was 19.3%, and for referable retinopathy it was 1.9%. For individuals screened after a year the prevalence of any retinopathy was 20.5% and referable retinopathy was 2.3% |
| 2. Any retinopathy at screening was associated with male sex (OR 1.19, 95% CI 1.14–1.25), HbA1c (OR 1.07, 95% CI 1.06–1.08), systolic BP (OR 1.06, 95% CI 1.05, 1.08), time to screening (OR for screening >1 year post diagnosis = 1.12, 95% CI 1.07–1.17) and obesity (OR 0.87, 95% CI 0.82–0.93) | |||||||
| Hayat et al. (26) | Pakistan | 100 | Yes (n = 100) | Nov 2009–Jun 2010 | 45.1 ± 3.2 | Female: 60 (60.0); Male: 40 (40.0) | 1.17% of type 2 DM patients had retinopathy within 1 month of diagnosis 2. Background retinopathy was predominant (12%) followed by pre-proliferative (4%) and proliferative (1%) lesions |
| Jammal et al. (18) | Jordan | 127 | Yes (n = 127) | 6 months | 49.7 ± 10.0 | Female: 46 (36.2); Male: 81 (63.8) | 1.7.9% DR in the included subjects 2. Patients with DR, 40% with significant macular edema 3. The odds of DR increased by 11% for each 1 year increase in age (odds ratio [OR] 1.11; 95% confidence interval [CI] 1.02–1.20). For each 1% increase in HbAlc, the odds of DR increased by 43% (OR 1.43; 95% CI 1.09–1.88) |
| Xu et al. (17) | China | 2602 | Not specified | 10 years | 64.6 ± 9.7 | N/A | 1.109 subjects (39 men) developed new DR with an incidence of 4.2% (95% CI: 3.45–5.03) 2. In multiple logistic regression analysis, incident DR was associated with higher HbA1c value (P = 0.001; OR = 1.73 95% CI: 1.35–2.21), longer duration of DM (P = 0.001; OR: 1.16; 95% CI: 1.10,1.22), higher serum concentration of creatinine (P = 0.02; OR: 1.01; 95% CI: 1.002,1.022), lower educational level (P = 0.049; OR: 0.74; 95% CI: 0.55,0.99), higher estimated cerebrospinal fluid pressure (P = 0.038; OR: 1.10; 95% CI: 1.01,1.22), and shorter axial length (P, 0.001; OR: 0.48; 95% CI: 0.33, 0.71) |
| Ponto et al. (25) | Germany | 285 | Yes (n = 285) | N/A | N/A | Female: 114 (40.0); Male: 171 (60.0) | 1. The weighted prevalence of DR in screening-detected type 2 DM was 13.0%; 12% of participants had a mild non-proliferative DR and 0.6% had a moderate nonproliferative DR 2. DR was proliferative in 0.3%. No cases of severe non-proliferative DR or diabetic maculopathy were found |
| Tóth et al. (31) | Germany | 3,523 | Yes (n = 44) | April–July 2015 | N/A | Female: 2,250 (63.9); Male: 1,273 (36.1) | 1.20% of participants with known DM had a blood glucose level ≥200 mg/dL, and 27.4% had never had an ophthalmological examination for DR 2. Prevalence of DR and/or maculopathy was 20.7% and prevalence of sight-threatening DR was 4.3% in one or both eyes among participants with DM |
| Al-Zamil et al. (32) | Saudi Arabia | 112 | Yes (n = 112) | Jan. 2012–Jan. 2015 | 51.2 ± 5.3 (DR: 53.4 ± 6.4) | Female: 62 (55.4); Male: 50 (44.6) | 1. DR was in seven patients (6.25%) 2. Two patients (28.6%) presented with bilateral clinically significant macular edema requiring further treatments 3. At the time of type 2 DM diagnosis, uncontrolled HbA1C levels were significantly associated with the presence of retinopathy (P = 0.045) |
| Chatziralli et al. (33) | United Kingdom | 1,062 | Yes (n = 1,062) | 2 years | 56.0 ± 10.9 | Female: 477 (44.9); Male: 585 (55.1) | Risk factors that remained significantly associated with DR presence at the multivariate analysis were male sex, any cardiovascular event, HbA1c, and IL-1RA |
| Rudnisky et al. (23) | Canada | 980 | Not specified | 10 years | DR status Progressed: 54.9 ± 12.7; Stable: 53.6 ± 13.7 | Female: 829 (84.6); Male: 151 (15.4) | 1. At baseline, most patients had no DR (n = 777, 79.3%) whereas 203 people (20.7%) had either nonproliferative DR (n = 179, 18.3%) or proliferative DR (n = 24, 2.5%) 2. Two-step progression occurred in 163 patients (16.6%), with only a minority of these individuals progressing to proliferative DR (n = 23). The median time to progression was 7.6 years. Multivariate Cox regression demonstrated that elevated hemoglobin A1C (hazard ratio [HR] = 1.42; P < 0.0001) and systolic BP (HR = 1.24; P = 0.009) were independent predictors of progression of DR |
| Voigt et al. (24) | Germany | 2,272 | Not specified | 1987–2014 | 65.4 ± 12.6 | N/A | 1.25.8 % of the patients had DR (20.2 % nonproliferative, 4.7 % proliferative, 0.7 % were not classified, 0.1 % blindness) 2. The prevalence of DR in dependence on diabetes duration was 1.1 % at diagnosis, 6.6 % after 0 < 5 years, 12 % after 5 < 10 years, 24 % after 10 < 15 years, 39.9 % after 15 < 20 years, 52.7 % after 20 < 25 years, 58.7 % after 25 <30 years and 63 % after ≥ 30 years 3. In a subset of 586 (25.7 %) patients with retinal photography of 3 consecutive years 7.0 % showed deterioration after 1 and 12.2 % after 2 years; 2.6 % improved after 1 and 2.8 % after 2 years. 201 (34.3 %) of this group had < 10 years diabetes and lower deterioration (4.5 % worsened after one and 9.5 % after 2 years). Their retinopathy mainly transformed from no retinopathy to nonproliferative. Four patients (2.0 %) developed proliferative retinopathy |
| Cui et al. (34) | China | 1,500 | Yes (n = 936) | September 2011–February 2012 | 59.5 ± 11.1 | Female: 886 (59.1); Male: 614 (40.9) | 1. Standardized prevalence rate of DR was 18.2% for all patients with diabetes, 32.8% for the patients with previously diagnosed diabetes, and 12.6% for newly diagnosed patients with T2DM. The prevalence rate of male DR was significantly higher than that of female DR (23.0% vs 14.1%, P < 0.001) 2. The prevalence rates of vision-threatening DR, diabetic macular oedema, and clinically significant macular oedema were 2.5%, 2.8% and 0.9%, respectively. Male, higher education level, longer duration of DM, higher systolic BP and glycosylated hemoglobin were independent risk factors for DR development |
| Hao et al. (35) | China | 947 | Yes (n = 947) | December 2018–April 2019 | No DR: 53.3 ± 11.7; DR: 52.9 ± 11.1 | Female: 381 (40.2); Male: 566 (59.8) | 1. BMI was shown to be a related factor for DR in patients with newly diagnosed diabetes (OR = 0.592, P = 0.004). When BMI was ≥28 kg/m2, heavy smoking was associated with DR (OR = 2.219, P = 0.049) 2. There was a negative correlation between DR and the age of diagnosis of diabetes ≥60 years (OR = 0.289, P = 0.009) |
| Hwang et al. (36) | Korea | 380 | Yes (n = 380) | Jan. 2013–Jan. 2018 | No DR: 51.61 ± 12.48; DR: 50.78 ± 10.21 | Female: 159 (41.8); Male: 221 (58.2) | 1.40 (10.53%) patients had DR at the initial ophthalmologic examination |
| 2. Glycated hemoglobin, fasting plasma glucose, urine albumin to creatinine ratio, and urine microalbumin level were significantly higher in DR patients than in patients without DR 3. In the multivariate logistic regression analysis, high HbA1C was a significant risk factor for the presence of DR at new T2DM diagnosis (OR: 2.372; P < 0.001). HbA1C, FPG, UACR, and urine microalbumin levels showed significantly positive correlations with DR severity |
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| Shah et al. (37) | United Kingdom | 11,399 | Yes (n = 11,399) | 2005–2009 | Median (IQR); At baseline; No DR: 60 (51–69); DR: 61 (52–69) | Female: 5,116 (45) Male: 6,283 (55) | 1. Baseline retinopathy prevalence was 18% (n = 2048) versus 37% in UKPDS. At 7 years, 11.6% (n = 237) of those with baseline retinopathy had progression of retinopathy 2. In those without baseline retinopathy, 46.4% (n = 4337/9351) developed retinopathy by 7 years. Retinopathy development (OR: 1.05; 95%CI: 1.02–1.07) and progression (OR: 1.05 [1.04–1.06]) at 7 years was associated with higher HbA1c at diabetes diagnosis. Obesity (OR: 0.88 [0.79–0.98]) and high socioeconomic status (OR: 0.63; 0.53–0.74) were negatively associated with retinopathy development at 7 years |