Table 2.
Subgroup analysis of the prevalence of preoperative anxiety among patients undergoing surgery by country, type of anxiety tool, quality of studies and economic level of a country
| Subgroup | Number of studies | Estimates | Heterogeneity across studies | ||
| Prevalence (%) | 95% CI | I2 (%) | P value | ||
| Country | |||||
| Ethiopia | 6 | 55.6 | 35.13 to 44.46 | 94.1 | <0.001 |
| Nigeria | 3 | 44.6 | 31.86 to 58.16 | 69.6 | 0.037 |
| Rwanda | 1 | 72.8 | 65.7 to 79.89 | – | – |
| Tunisia | 1 | 67.5 | 62.46 to 72.53 | – | – |
| Brazil | 5 | 44.4 | 23.76 to 64.95 | 97.1 | <0.001 |
| Srilanka | 1 | 77 | 68.75 to 85.25 | 96.6 | <0.001 |
| India | 3 | 75.6 | 56.72 to 94.49 | 69 | 0.040 |
| Pakistan | 3 | 65.4 | 59.4 to 71.39 | – | – |
| Turkey | 1 | 38.8 | 28.07 to 49.4 | – | – |
| Palestine | 1 | 57.5 | 52.08 to 62.9 | – | – |
| China | 1 | 20.6 | 9.83 to 31.67 | – | – |
| Iran | 1 | 47.2 | 40.76 to 53.63 | 97 | <0.001 |
| Anxiety tool used | |||||
| STAI | 11 | 57.8 | 45.80 to 69.78 | 97.9 | <0.001 |
| PITI | 2 | 64.3 | 47.85 to 80.78 | 91.7 | 0.001 |
| VAS | 3 | 56.6 | 37.16 to 76.17 | 96.1 | <0.001 |
| HADS-A | 3 | 35.3 | 23.77 to 46.90 | 82.6 | 0.003 |
| APAI | 4 | 64.9 | 55.78 to 74.10 | 83.4 | <0.001 |
| BAI | 3 | 39.6 | 33.29 to 46.02 | 0 | 0.964 |
| DASS | 1 | 87.5 | 82.37 to 92.62 | – | – |
| Quality of studies | |||||
| High | 16 | 54.8 | 44.28 to 65.28 | 97.8 | <0.001 |
| Moderate | 11 | 57.2 | 48.49 to 65.97 | 94.2 | <0.001 |
| Economy level of a country | |||||
| Low income | 11 | 54.9 | 47.69 to 62.17 | 92.6 | <0.001 |
| Middle income | 16 | 55.7 | 48.60 to 62.93 | 98 | <0.001 |
| Gender | |||||
| Male | 8 | 45.95 | 31.69 to 60.21 | 96.67 | <0.001 |
| Female | 9 | 59.36 | 48.16 to 70.52 | 95.43 | <0.001 |
| Region | |||||
| Africa | 11 | 55.91 | 48.37 to 63.44 | 99.31 | <0.001 |
| Asia | 9 | 62.59 | 48.65 to 76.53 | 97.48 | <0.001 |
| South America | 5 | 44.35 | 27.62 to 61.08 | 95.54 | <0.001 |
| Middle East | 2 | 52.50 | 42.41 to 62.59 | 82.63 | 0.02 |
APAI, Amsterdam Preoperative Anxiety and Information Scale; BAI, Beck Anxiety Inventory; DASS, Depression Anxiety and Stress Scale; HADS, Hospital Anxiety and Depression Scale; PITI, Preoperative Intrusive Thought Inventory; STAI, State-Trait Anxiety Inventory; VAS, Visual Analogue Scale.