Table 2.
Characteristics of the studies considered in the meta-analysis(DR).
| Study(Author, year) | Design(Type of study) | Number(male%) | Age at enrolment | Area (follow-up time, years) | Inclusion criteria | HbA1c variability and follow-up time | Mean HbA1c(%) | Outcome | Variable adjustment | NOS score |
|---|---|---|---|---|---|---|---|---|---|---|
| Hietala K et al.(2013) (58) | observational cohort study | 1346(52.08%) | 38.7±11.7 | Finland(NA) | adults patients with T1DM | CV:0.084±0.044, number of HbA1c measurements: 10(3-18) |
8.5±1.2 | proliferative retinopathy | Adjusted for renal status, diabetes duration, mean HbA1c, blood pressure, sex and number of HbA1c measurements. |
7 |
| Penno G et al.(2013) (59) | prospective cohort study | 8290(NA) | NA | Italia(NA) | caucasian patients with T2DM | SD:NA, NA |
4.52±0.76 | nonadvanced retinopathy | Adjusted for age, BMI, sex, known disease duration, smoking habits, TG, HDL-C, hypertension, dyslipidemia, previous major CVD events, specific treatments, and eGFR and albuminuria categories |
7 |
| Hermann JM et al.(2014) (60) | prospective cohort study | 35891(52.3%) | 16.2(13.1-18.0) | Germany(NA) | patients with T1DM | CV: 17.9(12.7–25.1), NA |
4.3 (3.5–5.3) | development of DR | Adjusted for gender, age at diagnosis and median HbA1c |
7 |
| Virk SA et al.(2016) (66) | prospective cohort study | 1706(47%) | NA | Canada(median follow-up period of 8.1 years) | patients with T1DM | SD:NA, CV:NA, number of HbA1c measurements: 22(14–29) |
NA | retinopathy | Adjusted for age, sex, diabetes duration, SBP, DBP, cholesterol, height, BMI, and socioeconomic disadvantage. | 6 |
| Takao T et al.(2017) (67) | retrospective cohort study | 486(83.3%) | 55.4±9.3 | Japan(NA) | patients with T2DM | CV:NA, NA |
7.9±1.7 | the development of mild-to-moderate NPDR | Adjusted for mean HbA1c, mean SBP, number of visits, age, sex, diabetes duration, BMI, TC/HDL-C, baseline smoking status, baseline alcohol intake, baseline use of insulin, and baseline use of ACEI. | 6 |
| Cardoso CRL et al.(2018) (68) | prospective cohort study | 654(38.1%) | 60.1(9.6) | Brazil(median follow-up period of 9.3 years (5.2–10.8)) | adults patients with T2DM | SD:NA, NA |
8.1(1.9) | retinopathy | Adjusted for age, sex and number of HbA1c or FG measurements, diabetes duration, BMI, smoking status, physical inactivity, arterial hypertension, number of anti-hypertensive drugs in use, ambulatory, 24-h SBP, presence of micro- and macrovascular complications at baseline, serum mean HDL-C and LDL-C, and use of insulin, statins and aspirin, mean fasting glycemia and HbA1c | 8 |
| Schreur V et al.(2018) (61) | observational cohort study | 415(46.99%) | NA | Netherlands(7-65 years, median follow-up period of 29 years) | patients with T1DM | CV:NA, NA |
NA | DR | NA | 6 |
| Rosa LCGFD et al.(2019) (69) | retrospective cohort study | 220(40%) | 29.6±10.1 | Brazil(>10 years) | adults patients with T1DM | Adjust-SD:1.24±0.88, CV:1.38±0.63, NA |
8.3±1.5 | retinopathy | Adjusted for age, sex, T1DM duration, presence of hypertension, and mean LDL-C levels | 6 |
| Slieker RC et al.(2019) (70) | prospective cohort study | 3898(NA) | NA | Netherlands(NA) | patients with T2DM | CV:NA, NA |
NA | retinopathy | Adjusted for sex, BMI, HDL, age at diagnosis, TG, HbA1c at baseline, oral glucose lowering drugs, insulin use and eGFR. | 6 |
| Song KH et al.(2019) (71) | retrospective cohort study. | 604(54.5%) | 60.7±10.8 | Korea(3 years) | patients with T2DM | SD:NA, 3-6 months |
7.32±1.04 | the progression of DR (worsening of the stage of DR) |
Adjusted for eGFR, TG to HDL-C ratio, the presence of DR, and use of ACEI or ARB. | 7 |
| Romero-Aroca P et al.(2021) (73) | prospective cohort study | 366(NA) | NA | Spain(12 years) | patients with T1DM | SD:NA, CV:NA, NA |
NA | DR/ DR severity |
Adjusted for current age, arterial hypertension, eGFR and mean-HbA1c. | 6 |
| Dai D et al.(2021) (62) | prospective cohort study | 315(60.6%) | 58.0±10.1 | China(NA) | patients with T2DM | CV:6.92±5.12, NA |
7.67±1.32 | DR | Adjusted for diabetes duration, smoking status, SBP, UACR, TG, fibrates using, and mean glycated albumin. |
7 |
| Hu J et al.(2021) (63) | observational cohort study | 3152(52.0%) | NA | Taiwan, China(median follow-up period of 3.95 years(2-5)) | patients with T2DM | SD:NA, NA |
DR:9.1 ± 2.1 No DR:8.5 ± 2.0 |
DR | Adjused for age, sex, diabetes duration, cataract prevalence, mean-HbA1c, HbA1c-SD, BMI, WHR, SBP, DBP, TC, TG, LDL, HDL | 7 |
| Kim HU et al.(2021) (64) | retrospective cohort study | 434(54.84%) | NA | Korea(NA) | patients with T2DM | CV: No DR development: 9.5±4.6, DR development: 11.4±5.9, NA |
No DR development:7.3±0.8 DR development:8.±1.0 |
any DR development/ moderate NPDR or worse DR |
Adjused for age, diabetes duration, insulin, SGLT-2 inhibitor, hemoglobin, TG, mean HbA1c, HbA1c ARV | 6 |
| Lee S et al.(2021) (72) | retrospective cohort study | 3137(NA) | NA | Hong Kong, China(10 years) | patients with T2DM | SD:1.1±0.71, CV:13.6±7.6, the average number of HbA1c measurements: 11.9±4.8 |
8.1±1.8 | Ophthalmological complications | NA | 6 |
| Wakasugi S et al.(2021) (74) | prospective cohort study | 999(60.9%) | 64.6±9.6 | Japan(NA) | patients with T2DM, age≥30 years and≤80 years | SD:2.04±0.63, NA |
7.1±0.8 | DR severity | Adjusted for age, gender, BMI, and duration of diabetes, SBP, TC, HDL-C, logarithm of TG, serum uric acid, eGFR, logarithm of urinary albumin excretion, smoker, alcohol consumption, use of insulin therapy, use of ACEI and/or ARB, use of statins, and use of antiplatelet agents and HbA1c |
8 |
| Ma C et al.(2022) (75) | observational cohort study | 2161(38.45%) | NA | China(NA) | patients with T2DM | Adjust-SD:NA, CV:NA, NA |
NA | diabetic eye disease events | Adjusted for gender, age, duration of T2DM, BMI, smoking, baseline concomitant disease, TG, LDL-C, blood pressure, anti-hyperglycemic therapy, and ACEI or ARB treatment, average HbA1c | 7 |
| Wu TE et al.(2022) (12) | prospective cohort study | 1869(50.4%) | 63.2±12.7 | Taiwan, China(median follow-up period of 9.5 years) | patients with T2DM | SD:0.728 ± 0.528, the average number of HbA1c measurements: 19, 10 to 42 |
8.06±1.77 | any retinopathy/advanced retinopathy | Adjusted for HbA1c-mean , age, sex, diabetes duration, blood pressure, BMI, TC, HDL-C, TG, and smoking status | 7 |
| Sun B et al.(2022) (76) | retrospective cohort study | 855(NA) | NA | China(median follow-up period of 4.8 years) | patients with T2DM | CV:NA, at 3, 6, 12, 18, 24 months, and every 6 months thereafter |
NA | New or worsening retinopathy | Adjusted for age, duration of diabetes, gender, BMI, current smoking status, SBP and DBP, TC, TG, HDL-C and LDL-C, baseline use of insulin and mean HbA1c during the first 24 months, history of major macrovascular diseases and microvascular diseases | 7 |
| Ma Y et al.(2023) (77) | retrospective cohort study | 387(61.5%) | 48.85±9.42 | China(median follow-up period of 4.5 years) | patients with T2DM | CV:9.17(6.54,12.55), NA |
7.31±1.57 | retinopathy | NA | 6 |
| Suh J et al.(2023) (78) | retrospective cohort study | 201(43.8%) | NA | Korea(median follow-up period of 16.4 years) | children and adolescents with T1DM | Adjust-SD:1.04±0.58, 3 months |
NA | retinopathy | Adjusted for age, duration of disease, and sex | 7 |
| Dehghani Firouzabadi F et al.(2024) (66) | prospective cohort study | 1145(50.04%) | NA | Iran(10 years) | patients with T2DM | CV:NA, 3 months |
Developed retinopathy: 7.85±0.82; Did not develop Retinopathy: 7.54±0.83 |
incidence of retinopathy | NA | 6 |
| Teh XR et al.(2025) (79) | retrospective cohort study | 40662(38.3%) | 57.2(13.9) | Thailand(10 years) | patients with T2DM | SD:0.67(0.87), CV:0.07(0.08), 3-6 months |
7.7(2.0) | DR | Adjusted for age, gender, insurance scheme, BMI, TC, LDL, HDL, TG, haemoglobin, SBP/DBP, hypertension, dyslipidemia, presence of T2DM complications (CVD, DR, or CKD) prior to the outcome of interest, medication use in terms of drug classes (biguanides, sulphonylurea, insulin, alpha-glucosidase inhibitors, DPP-4i, GLP1-RA, TZD, SGLT-2 inhibitors , meglitinides, statins) and the number of antihypertensive drugs |
8 |
DR, diabetes retinopathy; HbA1c, glycated hemoglobin A1C; NOS, Newcastle-Ottawa Scale; T1DM, Type 1 Diabetes Mellitus; NA, not available; CV, coefficient of variation; T2DM, Type 2 Diabetes Mellitus; SD, standard deviation; BMI, mean body mass index; HDL-C, high-density lipoprotein cholesterol; CVD, cardiovascular disease; eGFR, estimated glomerular filtration rate; SBP, systolic blood pressure; DBP, diastolic blood pressure; NPDR, non-proliferative diabetic retinopathy; TC, total cholesterol; ACEI, angiotensin-converting enzyme inhibitor; FG, fasting glucose; LDL-C, low-density lipoprotein cholesterol; HDL, high-density lipoprotein; ARB, angiotensin-converting enzyme receptor blocker; UACR, urine albumin-to-creatinine ratio; TG, triglyceride; NDR, non-diabetic renal disease; WHR, waist-to-hip ratio; LDL, low-density lipoprotein; SGLT-2, sodium-glucose cotransporter-2; ARV; DM, diabetes mellitus; CKD, chronic kidney disease; DPP-4i, dipeptidyl peptidase-4 inhibitors; GLP1-RA, glucagon-like peptide-1 agonists; TZD, thiazolidinedione.
Studies are presented in chronological order of publication.