Table 3.
Subgroup analysis of the source of heterogeneity of the meta-analysis of prevalence of prolonged grief disorder symptoms
| Subpopulation by variable | Number of studies | Sample size | Number of grieving individuals | Heterogeneity, I2 (%), P |
Pooled prevalence (95% CI), % | Q (P) | |
| Study site | Online and offline | 2 | 871 | 34 | 77.76, 0.030 | 3.83 (2.22 to 6.31) | |
| Online | 4 | 870 | 191 | 68.34, 0.020 | 22.00 (19.32 to 24.80) | 45.68 (<0.001) | |
| Offline | 8 | 2398 | 1288 | 98.61, <0.001 | 50.92 (31.91 to 65.60) | 44.28 (<0.001) | |
| Type of the bereavement* | Death due to illness | 6 | 2055 | 314 | 95.80, <0.001 | 13.60 (6.42 to 26.71) | |
| Death due to earthquake | 3 | 1300 | 986 | 93.42, <0.001 | 80.38 (70.27 to 87.71) | 44.83 (<0.001) | |
| Death due to AIDS | 2 | 188 | 66 | 0.01, 0.970 | 35.11 (28.63 to 42.20) | 7.43 (0.006) | |
| Death of the only child | 1 | 149 | 43 | Not applicable | 28.90 (22.21 to 36.62) | 4.17 (0.041) | |
| Death due to COVID-19 | 2 | 447 | 104 | 87.93, <0.001 | 30.72 (16.11 to 50.50) | 2.93 (0.087) | |
| Sample size† | >226 | 7 | 3387 | 1146 | 99.34, <0.001 | 24.00 (8.32 to 52.32) | |
| ≤226 | 7 | 752 | 367 | 96.22, <0.001 | 28.90 (25.11 to 61.64) | 1.26 (0.262) | |
| Sampling method | Convenience | 12 | 3764 | 1269 | 98.72, <0.001 | 27.84 (15.31 to 45.02) | |
| Probability | 2 | 375 | 244 | 99.13, <0.001 | 64.42 (18.31 to 93.64) | 1.87 (0.172) | |
| % of males among the study sample† | ≤37.0 | 7 | 2348 | 905 | 99.10, <0.001 | 28.91 (9.12 to 62.40) | |
| >37.0 | 7 | 1791 | 608 | 97.43, <0.001 | 36.01 (23.42 to 50.94) | 0.17 (0.680) | |
| Mean age of the study sample‡ | 18–35 years | 3 | 1293 | 126 | 97.61, <0.001 | 6.92 (2.28 to 19.01) | |
| 36–59 years | 9 | 2345 | 1273 | 98.42, <0.001 | 49.74 (32.11 to 67.42) | 13.81 (<0.001) | |
| 60+years | 2 | 501 | 114 | 77.48, <0.001 | 23.50 (18.12 to 30.01) | 5.43 (0.020) | |
| Assessment of PGD symptoms | ICG | 11 | 3497 | 1362 | 98.90, <0.001 | 34.92 (17.00 to 58.51) | |
| Others | 3 | 642 | 151 | 34.86, 0.220 | 23.52 (20.41 to 27.02) | 1.21 (0.272) | |
| Survey method | Self-report | 6 | 1682 | 381 | 98.81, <0.001 | 22.46 (7.01 to 52.74) | |
| Interview | 8 | 2457 | 1132 | 98.72, <0.001 | 41.10 (24.00 to 60.72) | 1.21 (0.272) | |
| JBI checklist score | 3–5 | 7 | 1229 | 238 | 93.14, <0.001 | 24.92 (15.23 to 38.00) | |
| 6–7 | 7 | 2910 | 1275 | 99.20, <0.001 | 40.42 (14.91 to 72.33) | 0.89 (0.347) | |
*Studies that included participants bereaved by the loss of loved ones due to a variety of causes of death, primarily illnesses, were categorised as ‘death due to illness’. Studies that included participants bereaved by the loss of loved ones solely due to earthquakes, AIDS and COVID-19 were categorised as ‘death due to earthquake’, ‘death due to AIDS’ and ‘death due to COVID-19’, respectively. Studies that included participants who lost their only child, regardless of the causes of death, were categorised as ‘death of the only child’.
†The two continuous variables were dichotomised at the median value.
‡Studies with the mean age of the sample being ‘18–35 years’, ‘36–59 years’ and ‘60+years’ were crudely categorised into studies with predominantly young, middle-aged and older adults, respectively.
CI, confidence interval; ICG, Inventory of Complicated Grief; PGD, prolonged grief disorder.