Table 2 The prevalence of ROP based on region, gender, provinces and quality of studies
Variable | Studies (Na) | Sample (N) | Heterogeneity | 95% CIb | Prevalence (%) | ||
|---|---|---|---|---|---|---|---|
I2 | P-Value | ||||||
Region | Center | 20 | 12,355 | 93.65 | < 0.001 | 21.8 to 28.4 | 24.9 |
East | 4 | 302 | 57.79 | 0.07 | 17 to 33 | 24.1 | |
North | 12 | 2626 | 97.09 | < 0.001 | 15.9 to 37.1 | 25 | |
South | 4 | 2586 | 98.60 | < 0.001 | 9.2 to 37.1 | 20.5 | |
West | 2 | 131 | 0 | 0.67 | 7.6 to 19.1 | 12.3 | |
Test for subgroup differences: Q = 9.67, df(Q) = 4, P = 0.046 | |||||||
Gender | Boys | 11 | 1467 | 92.65 | < 0.001 | 11.9 to 28.5 | 18.9 |
Girls | 11 | 1184 | 85.02 | < 0.001 | 12.8 to 25.4 | 18.3 | |
Rate ratio of boys to girls: ORc = 1.07(0.86 to 1.33, P = 0.501) | |||||||
Provinces | Khozestan | 1 | 576 | 0 | – | 28.3 to 35.9 | 32 |
Mazandaran | 8 | 1678 | 95.77 | < 0.001 | 23.5 to 48.2 | 34.8 | |
Isfahan | 4 | 1600 | 92.48 | < 0.001 | 16.5 to 35 | 24.6 | |
Golestan | 1 | 89 | 0 | – | 2.3 to 12.8 | 5.6 | |
Kerman | 1 | 83 | 0 | – | 20.3 to 39.6 | 29 | |
Kermanshah | 3 | 84 | 0 | – | 7.4 to 22.1 | 13.1 | |
Razavi Khorasan | 3 | 219 | 67.89 | 0.044 | 12.4 to 34.2 | 21.3 | |
Guilan | 1 | 310 | 0 | – | 16.5 to 25.5 | 20.9 | |
Kurdistan | 1 | 47 | 0 | – | 4.5 to 23.1 | 10.6 | |
Semnan | 1 | 270 | 0 | – | 0.4 to 3.4 | 1.1 | |
Fars | 3 | 2010 | 99.09 | < 0.001 | 4 to 50.8 | 17.2 | |
East Azarbaijan | 2 | 549 | 91.32 | 0.001 | 4.6 to 25 | 11.3 | |
Tehran | 14 | 10,407 | 91.32 | < 0.001 | 25.1 to 31 | 28 | |
Zanjan | 1 | 78 | 0 | – | 0.2 to 8.5 | 1.2 | |
Test for subgroup differences: Q = 97.59, df(Q) = 13, P < 0.001 | |||||||
Quality | Medium | 20 | 7760 | 63.68 | < 0.001 | 16.6 to 28.0 | 23.5 |
High | 22 | 10,240 | 96.65 | < 0.001 | 19.1 to 28.7 | 23.5 | |
Test for subgroup differences: Q = 0, df(Q) = 1, P = 0.995 | |||||||