Table 2 Subgroup analysis of prevalence of GERD
From: Epidemiology of gastroesophageal reflux disease in Iran: a systematic review and meta-analysis
Variable | Studies (N) | Sample (N) | Heterogeneity | 95% CI | Pooled prevalence (%) | ||||
|---|---|---|---|---|---|---|---|---|---|
Total subjects | Event | I2 | P-Value | ||||||
Daily | Areas | Center | 6 | 12,884 | 680 | 98.44 | <  0.001 | 2.37–8.47 | 4.52 |
East | 2 | 2066 | 254 | 98.54 | <  0.001 | 3.21–29.70 | 10.58 | ||
North | 2 | 51,448 | 5947 | 98.98 | <  0.001 | 1.09–23.40 | 5.48 | ||
Test for subgroup differences: Q = 1.559, df(Q) = 2, P = 0.459 | |||||||||
Population | Blood donors | 1 | 3517 | 165 | – | – | 4.05–5.45 | 4.70 | |
General population | 8 | 59,873 | 6653 | 98.18 | <  0.001 | 4.51–9.45 | 6.56 | ||
Health care worker | 1 | 3008 | 63 | – | – | 1.64–2.68 | 2.10 | ||
Test for subgroup differences: Q = 38.389, df(Q) = 2, P <  0.001 | |||||||||
Year of studies | 1991–2004 | 6 | 11,691 | 849 | 98.65 | <  0.001 | 4.03–13.07 | 7.37 | |
2005–2013 | 4 | 54,707 | 6032 | 99.01 | <  0.001 | 1.20–10.51 | 3.64 | ||
Test for subgroup differences: Q = 1.256, df(Q) = 1, P = 0.263 | |||||||||
Quality of studies | Low risk | 5 | 55,271 | 6282 | 98.52 | <  0.001 | 4.21–12.39 | 7.31 | |
Moderate risk | 5 | 11,127 | 600 | 98.46 | <  0.001 | 2.08–8.54 | 4.26 | ||
Test for subgroup differences: Q = 1.380, df(Q) = 1, P = 0.240 | |||||||||
Method of data collection | Questionnaire + Interview | 7 | 61,932 | 6337 | 99.06 | <  0.001 | 2.14–7.81 | 4.12 | |
Interview | 3 | 4466 | 545 | 98.91 | <  0.001 | 6.53–18.38 | 11.14 | ||
Test for subgroup differences: Q = 5.488, df(Q) = 1, P = 0.019 | |||||||||
Sex | The odds ratio of females to males: 1.503 (95% CI: 1.153–1.59, P = 0.003); Heterogeneity: I2: 68.49%, P = 0.013 | ||||||||
Weekly | Areas | Center | 9 | 42,825 | 4880 | 99.34 | <  0.001 | 7.92–15.92 | 11.31 |
East | 2 | 2066 | 258 | 0 | 0.784 | 11.15–14.01 | 12.51 | ||
North | 4 | 52,938 | 4317 | 91.08 | <  0.001 | 7.04–11.38 | 8.98 | ||
South | 4 | 12,559 | 2955 | 97.89 | <  0.001 | 15.22–28.89 | 21.26 | ||
Test for subgroup differences: Q = 17.025, df(Q) = 3, P = 0.001 | |||||||||
Population | Blood donors | 1 | 3517 | 197 | – | – | 4.89–6.41 | 5.60 | |
General population | 14 | 98,005 | 10,770 | 99.69 | <  0.001 | 10.07–17.91 | 13.52 | ||
Health care worker | 4 | 8866 | 1443 | 99.20 | <  0.001 | 5.17–7.39 | 11.44 | ||
Test for subgroup differences: Q = 29.288, df(Q) = 2, P <  0.001 | |||||||||
Year of studies | 1991–2004 | 8 | 14,570 | 1453 | 97.25 | <  0.001 | 7.86–13.56 | 10.37 | |
2005–2013 | 11 | 95,818 | 10,957 | 99.70 | <  0.001 | 9.95–20.04 | 14.27 | ||
Test for subgroup differences: Q = 1.947, df(Q) = 1, P = 0.163 | |||||||||
Quality of studies | Low risk | 10 | 90,079 | 10,262 | 99.71 | <  0.001 | 9.85–20.74 | 14.47 | |
Moderate risk | 9 | 20,309 | 2149 | 98.26 | <  0.001 | 7.65–14.46 | 10.58 | ||
Test for subgroup differences: Q = 1.544, df(Q) = 1, P = 0.214 | |||||||||
Method of data collection | Interview | 3 | 4466 | 568 | 0 | 0.892 | 11.77–13.73 | 12.72 | |
Questionnaire | 3 | 6170 | 1313 | 96.95 | <  0.001 | 10.71–25.45 | 16.83 | ||
Questionnaire + Interview | 13 | 99,752 | 10,529 | 99.61 | <  0.001 | 8.38–15.92 | 11.63 | ||
Test for subgroup differences: Q = 1.815, df(Q) = 2, P = 0.404 | |||||||||
Sex | The odds ratio of females to males: 1.174 (95% CI: 0.974–1.414, P = 0.092); Heterogeneity: I2: 91.63%, P <  0.001 | ||||||||
Monthly | Areas | Center | 7 | 17,646 | 3591 | 97.55 | <  0.001 | 15.36–22.91 | 18.84 |
East | 1 | 1066 | 161 | – | – | 13.86–16.42 | 15.10 | ||
North | 3 | 52,037 | 20,720 | 99.64 | <  0.001 | 6.22–46.66 | 19.42 | ||
Test for subgroup differences: Q = 3.177, df(Q) = 2, P = 0.204 | |||||||||
Population | Blood donors | 1 | 3517 | 795 | 98.91 | <  0.001 | 21.25–24.01 | 22.60 | |
General population | 8 | 63,635 | 23,110 | 99.71 | <  0.001 | 12.44–28.62 | 19.27 | ||
Health care worker | 2 | 3597 | 567 | 98.23 | <  0.001 | 11.92–18.40 | 14.87 | ||
Test for subgroup differences: Q = 14.531, df(Q) = 2, P = 0.001 | |||||||||
Year of studies | 1991–2004 | 6 | 15,453 | 3323 | 95.89 | <  0.001 | 17.14–23.54 | 20.15 | |
2005–2013 | 5 | 55,296 | 21,149 | 99.70 | <  0.001 | 7.27–34.71 | 16.95 | ||
Test for subgroup differences: Q = 0.181, df(Q) = 1, P = 0.671 | |||||||||
Quality of studies | Low risk | 5 | 55,271 | 21,159 | 99.70 | <  0.001 | 7.82–35.92 | 17.90 | |
Moderate risk | 6 | 15,478 | 3313 | 96.03 | <  0.001 | 16.42–22.85 | 19.43 | ||
Test for subgroup differences: Q = 0.042, df(Q) = 1, P = 0.838 | |||||||||
Method of data collection | Interview | 3 | 8228 | 1891 | 97.45 | <  0.001 | 15.89–26.03 | 20.50 | |
Questionnaire + Interview | 8 | 62,521 | 22,581 | 99.70 | <  0.001 | 10.79–28.45 | 17.99 | ||
Test for subgroup differences: Q = 0.233, df(Q) = 1, P = 0.637 | |||||||||
Sex | The odds ratio of females to males: 1.126 (95% CI: 0.849–1.494, P = 0.411); Heterogeneity: I2: 96.68%, P <  0.001 | ||||||||
Overall | Areas | Center | 6 | 12,884 | 4823 | 97.38 | <  0.001 | 32.01–42.62 | 37.16 |
East | 1 | 1066 | 493 | – | – | 43.26–49.24 | 46.24 | ||
North | 1 | 49,975 | 30,415 | – | – | 60.43–61.26 | 60.86 | ||
South | 1 | 9264 | 5419 | – | – | 57.49–59.50 | 58.50 | ||
Test for subgroup differences: Q = 169.751, df(Q) = 3, P <  0.001 | |||||||||
Population | Blood donors | 1 | 3517 | 1157 | – | – | 31.37–34.47 | 32.90 | |
General population | 7 | 66,664 | 38,913 | 99.43 | <  0.001 | 38.49–53.12 | 45.71 | ||
Health care worker | 1 | 3008 | 1080 | 99.09 | <  0.001 | 34.20–37.63 | 35.90 | ||
Test for subgroup differences: Q = 16.155, df(Q) = 2, P <  0.001 | |||||||||
Year of studies | 1991–2004 | 5 | 10,691 | 4124 | 97.26 | <  0.001 | 34.36–46.09 | 40.09 | |
2005–2013 | 4 | 62,498 | 37,026 | 99.59 | <  0.001 | 37.71–56.28 | 46.89 | ||
Test for subgroup differences: Q = 1.458, df(Q) = 1, P = 0.227 | |||||||||
Quality of studies | Low risk | 5 | 63,062 | 37,471 | 99.15 | <  0.001 | 43.12–56.23 | 49.67 | |
Moderate risk | 4 | 10,127 | 3679 | 98.20 | <  0.001 | 28.59–42.77 | 35.36 | ||
Test for subgroup differences: Q = 8.008, df(Q) = 1, P = 0.005 | |||||||||
Method of data collection | Questionnaire + Interview | 7 | 69,723 | 39,541 | 99.73 | <  0.001 | 32.71–52.17 | 42.14 | |
Interview | 2 | 3466 | 1609 | 0 | <  0.001 | 44.76–48.08 | 46.42 | ||
Test for subgroup differences: Q = 0.692, df(Q) = 1, P = 0.406 | |||||||||
Sex | The odds ratio of females to males: 1.111 (95% CI: 0.888–1.391, P = 0.358); Heterogeneity: I2: 97.96%, P <  0.001 | ||||||||