Table 2.
The Result of Meta-regression Analysis and the Pooled Standard Mean Difference for Depression and Anxiety Levels According to Subgroup Analysis
| Subgroup | No. of studies | SMD (95% CI) | P-value | Heterogeneity | Meta-regression | ||
|---|---|---|---|---|---|---|---|
|
| |||||||
| I2 (%) | Pha | P-value | |||||
| Depression | Overall | 27 | 0.76 (0.62–0.90) | < 0.001 | 77.2 | < 0.001 | |
| Studied region | 0.007 | ||||||
| East Asia | 8 | 0.50 (0.32–0.69) | < 0.001 | 56.3 | 0.025 | ||
| USA | 7 | 0.74 (0.52–0.96) | < 0.003 | 77.2 | 0.003 | ||
| Europe | 7 | 0.91 (0.52–1.30) | < 0.001 | 83.9 | < 0.001 | ||
| Othersb | 5 | 1.10 (0.70–1.49) | < 0.001 | 78.6 | 0.001 | ||
| IBS criteria | 0.197 | ||||||
| Rome II | 11 | 0.91 (0.60–1.15) | < 0.001 | 80.0 | < 0.001 | ||
| Rome III | 10 | 0.65 (0.40–0.90) | < 0.001 | 80.4 | < 0.001 | ||
| Othersc | 6 | 0.70 (0.46–0.93) | < 0.001 | 65.4 | 0.013 | ||
| The type of depression questionnaire | < 0.001 | ||||||
| HADS | 14 | 1.02 (0.83–1.21) | < 0.001 | 66.3 | < 0.001 | ||
| BDI | 5 | 0.73 (0.55–0.91) | < 0.001 | 0.0 | 0.713 | ||
| SDS | 4 | 0.41 (0.14–0.68) | < 0.001 | 71.4 | 0.015 | ||
| Others | 4 | 0.52 (0.33–0.70) | < 0.001 | 57.6 | 0.069 | ||
| Anxiety | Overall | 27 | 0.84 (0.67–1.01) | < 0.001 | 85.6 | < 0.001 | |
| Studied region | 0.002 | ||||||
| East Asia | 8 | 0.51 (0.29–0.73) | < 0.001 | 68.5 | 0.002 | ||
| USA | 7 | 0.76 (0.45–1.07) | < 0.001 | 85.0 | < 0.001 | ||
| Europe | 7 | 0.92 (0.55–1.29) | < 0.001 | 74.8 | < 0.001 | ||
| Othersb | 5 | 1.38 (0.81–1.95) | < 0.001 | 88.9 | < 0.001 | ||
| IBS criteria | 0.997 | ||||||
| Rome II | 11 | 0.90 (0.66–1.14) | < 0.001 | 79.2 | < 0.001 | ||
| Rome III | 10 | 0.86 (0.51–1.21) | < 0.001 | 90.1 | < 0.001 | ||
| Othersc | 6 | 0.72 (0.36–1.07) | < 0.001 | 85.3 | < 0.001 | ||
| The type of anxiety questionnaire | 0.007 | ||||||
| HADS | 15 | 1.16 (0.94–1.38) | < 0.001 | 74.8 | < 0.001 | ||
| STAI | 5 | 0.32 (0.10–0.53) | 0.004 | 48.5 | 0.100 | ||
| SAS | 2 | 0.70 (0.48–0.93) | < 0.001 | 0.0 | 0.878 | ||
| Others | 5 | 0.59 (0.33–0.86) | < 0.001 | 82.7 | < 0.001 | ||
a
P-value of heterogeneity analysis.
b
Two studies in Australia, 1 in Brazil, 1 in India, and 1 in Malaysia.
c
Three studies using the Bowel Disease Questionnaire, 2 studies using Manning’s criteria and 1 study using Rome I criteria.
SMD, standard mean difference; IBS, irritable bowel syndrome; BDI, Beck Depression Inventory; HADS, Hospitalization Anxiety and Depression Scale; SAS, Self-Rating Anxiety Scale; SDS, Self-Rating Depression Scale; STAI, State and Trait Anxiety Inventory.