Table 1 Characteristics of included study
No. | Author, Year | Design Study | Age (mean ± SD, years) | Population | Diagnosis of DR | DR groups | Differential Count Ratio Profile | Findings |
|---|---|---|---|---|---|---|---|---|
1 | Abdullah, 2021 [15] | case–control | DR 7.36 ± 8.35; no DR 55.24 ± 10.83 | India | ICDR severity scales | no DR and DR | NLR | NLR were higher in DR group |
2 | Akdogan, 2016 [16] | retrospective cohort | 59.8 ± 9.2 | Turkey | dilated funduscopy | control, DM without DR, DM with DR | NLR and PLR | PLR were higher in DR compared to control. No difference in NLR group |
3 | Atli, 2022 [17] | cross-sectional | NPDR 61.44 ± 6.25; PDR 60.86 ± 4.70; no DR 56.15 ± 10.03; control 43.10 ± 7.82 | Turkey | digital fundus based on ETDRS | control, no DR, NPDR and PDR | NLR and PLR | higher NLR and PLR in PDR group |
4 | Bhattacharyya, 2021 [18] | cross-sectional | 59.89 ± 10.9 | India | ICDR severity scale | DM with nephropathy, neuropathy, and retinopathy | NLR | NLR higher in DM with more than one microvascular complication |
5 | Chittawar, 2017 [19] | cross-sectional | 51.12 ± 11.28 | India | comprehensive assessment include dilated funduscopy and fundus FA based on ETDRS | DM only | NLR | Higher quartile NLR (2.60–6.28) increase DR incidence |
6 | Cardoso, 2021 [20] | prospective cohort | 60.0 ± 9.6 | Brazil | comprehensive assessment includes dilated funduscopy, OCT macula based on ICDR severity scale | microvascular DR and macrovascular complications | NLR, PLR, MLR | no hematological parameter was predictive of any microvascular outcome including retinopathy |
7 | Ciray, 2015 [21] | cross-sectional | 59.7 ± 11.3 | Turkey | dilated funduscopy based on ICDR severity scale | NPDR and PDR | NLR | Higher NLR was not associated with DR and severity of DR |
8 | Dascalu AM, 2023 (a) [11] | retrospective cohort | no DR 66.9 ± 5.76; NPDR 66.4 ± 6.07; PDR 62.0 ± 10.59 | Romania | Visual Evoked Potentials | no DR, NPDR, PDR | NLR, PLR | Higher NLR associated with PDR. PLR were not different statistically among groups |
9 | Dascalu AM, 2023 (b) [10] | retrospective cohort | 65.6 ± 8.9 | Romania | examination microdots, blot hemorrhage, hard exudates, soft exudates, and new vessel formation | no DR, NPDR, PDR | NLR, PLR, MLR, SII | Higher NLR, MLR, MPV, and SII associated with PDR group. PLR were not associated with DR |
10 | Dogan, 2024 [22] | retrospective cohort | no DR 53.1 ± 6.9; NPDR 54.3 ± 7.1; PDR 55.7 ± 5.9; control 53.8 ± 7.4 | Turkey | comprehensive examination include dilated fundus and fundus photography | control, no DR, NPDR and PDR | NLR, MLR, PLR, SII | NLR, PLR and SII were higher in NPDR and PDR groups. MLR were not significantly higher in NPDR or PDR group |
11 | El-Tawab, 2023 [23] | case–control | DR 50.48 ± 7.98; control 52.47 ± 8.85 | Egypt | N/A | PDR and no PDR | NLR | NLR associated with DR |
12 | Fawwad, 2018 [24] | retrospective cohort | no DR 52.33 ± 11.05; microvascular complications 55.86 ± 10.72 | Pakistan | digital retina photographs | no DR and DR | NLR | NLR associated with DR |
13 | Gao Y, 2024 [25] | retrospective cohort | no DR 53.78 ± 1.88; NPDR 51.72 ± 1.64; PDR 53.00 ± 1.52 | China | fundus photography, FFA, and OCT based on ICDR severity scale | no DR, NPDR, PDR | NLR, PLR, SII | NLR, PLR and SII were associated with DR and DR stages |
14 | He X, 2022 [26] | cross-sectional | 61.3 ± 13.2 | US | comprehensive asessment based on ETDRS and ICDR severity scale | no DR and DR | NLR | NLR associated with DR |
15 | Huang Q, 2021 [27] | cross-sectional | 61 ± 13.85 | China | N/A | control, DM without DR, NPDR, PDR, | MLR | MLR were higher in PDR group |
16 | Ilhan C, 2019 [28] | Prospective case–control | Control 62.68 ± 10.40; NPDR 61.14 ± 9.33; PDR 59.63 ± 7.07 | Turkey | based on IAO in 2002 | control, severe NPDR, PDR | NLR, MLR, PLR | NLR associated with DR. MLR and PLR were not different among groups |
17 | Ilhan C, 2020 [29] | prospective cohort | control 63.54 ± 5.68; DME 58.22 ± 11.35; non-DME 61.92 ± 6.82 | Turkey | fundus examination | control, NPDR with DME, NPDR without DME | NLR, MLR, PLR | NLR and MPV/L were higher in DME group. MLR and PLR were not different among groups |
18 | Lei C, 2023 [30] | cross-sectional | 55.46 ± 10.08 | China | medical records | PDR with DME, PDR without DME | NLR, PLR, MLR, SII | NLR, PLR, LMR, and SII were not associated with CMT/DME |
19 | Li J, 2024 [13] | cross-sectional | 54.67 ± 12.86 | China | non-mydriatic fundus photography based on ICDR severity scale | no DR and DR | NLR, PLR, SII | NLR, PLR and SII were associated with DR |
20 | Mahajan, 2023 [31] | prospective cohort | 56.3 ± 13.24 | India | dilated funduscopy based on ICDR severity scale | DR | NLR | Higher NLR in DR group. NLR associated with increased risk of microvascular complications |
21 | Moursy, 2015 [32] | retrospective cohort | DR 56.19 ± 7.27; no DR 53.60 ± 6.15; control 53.50 ± 6.66 | Egypt | based on Global DR Project Group | no DR, NPDR, PDR | NLR | NLR were significantly higher in NPDR and PDR group compared to no DR. NLR were not significantly higher in PDR compared to NPDR |
22 | Ozturk, 2013 [33] | cross-sectional | DR 66.60 ± 4.20; no DR 66.78 ± 4.12 | Turkey | non-mydriatic fundus photography based on ETDRS | no DR and DR | NLR | NLR were higher in diabetic group with complications |
23 | Rajendrakumar AL, 2023 [34] | retrospective cohort | 61.7 ± 12.7 | Scottish | based on ICDR severity scale | developed DR, death without DR, no DR | NLR | NLR associated with DR |
24 | Sari, 2021 [35] | case–control | N/A | Indonesia | based on ICDR severity scale | no DR, NPDR, PDR | NLR, PLR, MLR | NLR and PLR were not significantly higher in DR. MLR were insignificantly lower in DR compared to control |
25 | Tang Y, 2024 [36] | retrospective cohort | no DR 47.3 ± 11.2; DR 52.4 ± 10.9 | China | dilated fundus, FA, and SD-OCT | no DR and DR | NLR | NLR associated with DR |
26 | Ulu SM, 2013 [37] | cross-sectional | control 48.38 ± 5.45; DM 50.31 ± 5.20 | Turkey | undilated fundus | control, DM without DR, DM with DR | NLR | Higher NLR associated with DR and correlated with DR grades |
27 | Wan H, 2020 [38] | cross-sectional | 67 ± 9 | China | non-mydriatic fundus photography by ophthalmologist based on ICDR severity scale | DR, NPDR, PDR | NLR | Higher NLR were not associated with prevalence of DR |
28 | Wang H, 2022 [14] | cross-sectional | 63.8 ± 10.8 | US | dilated funduscopy and OCT based on ETDRS | no DR, NPDR, PDR | MLR | MLR were associated with PDR |
29 | Wang JR, 2020 [39] | cross-sectional | no DR 55.44 ± 11.27; DR 56.48 ± 9.86 | China | dilated color fundus photography | no DR and DR | NLR, PLR, MLR | NLR and PLR associated with DR. MLR were not associated with DR |
30 | Wang RT, 2015 [40] | cross-sectional | control 58.7 ± 5.9; no DR 60.3 ± 6.0; DR 66.6 ± 5.8 | China | N/A | control, DM without DR, DM with DR | NLR | NLR were higher in DR group |
31 | Wang S, 2023 [41] | cross-sectional | no DR 59 ± 4.25 DR 60, 3.43 | China | N/A | no DR and DR | SII | SII were higher in DR groups and associate dwith DR |
32 | Xiaodong L, 2023 [42] | cross-sectional | 57.8 ± 10.52 | China | N/A | NPDR, PDR, NPDR with DN, and PDR with DN | NLR and PLR | NLR and PLR were higher in DR with DN compared to DR group only |
33 | Yanxia C, 2024 [43] | retrospective cohort | early 59.06 ± 11.74; advanced 60.34 ± 9.65; severe 61.37 ± 8.59; atrophic 61.71 ± 13.11 | China | N/A | early, advanced, severe and atrophic DME | NLR, MLR, PLR, SII | SII and the decline in SRF and HRF ≥ were associated with DME stages |
34 | Yeter DY, 2022 [44] | retrospective cohort | 63 ± 8.5 | Turkey | N/A | DR without DME, DR with DME, DM without DR/DME | NLR and MHR | NLR and MHR were associated with DME |
35 | Yue Song, 2015 [45] | case–control | no DR 55.75 ± 11.11; NPDR 53.31 ± 10.56; PDR 56.00 ± 8.89 | China | funduscopy based on ISO | DM without DR, NPDR, PDR | NLR, MLR, PLR | Higher NLR and PLR in DR group. Only MLR were associated with DR independently |
36 | Zeng J, 2022 [46] | retrospective cohort | no DR 55.23 ± 10.19; NPDR 57.69 ± 9.56; PDR 55.83 ± 8.18 | China | Medical records | control, NPDR, PDR | NLR, MLR, PLR | NLR, PLR, MLR were higher in DR groups. Only PLR were associated with DR risk independently |
37 | Zhang P, 2021 [47] | cross-sectional | DR 68.33 ± 8.40; no DR 68.10 ± 8.47 | China | dilated fundus | no DR and DR | NLR | NLR were higher in DR group |
38 | Zhu Y, 2022 [48] | retrospective cohort | no-DME 56.38 ± 10.51; DME 56.00 ± 8.25 | China | OCT based on ESASO classification | severe DR with DME, severe DR without DME | NLR, MLR, PLR | NLR, PLR, MLR, MHR was not different among groups |