for the main comparison.
| Written emotional disclosure compared with neutral writing for asthma | ||||||
|
Patient or population: adults and children with asthma Settings: home, healthcare, community and university settings Intervention: written emotional disclosure Comparison: neutral writing | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Neutral writing | Written emotional disclosure | |||||
|
Average FEV1 % predicted value Follow‐up: 2 to 3 months |
Mean FEV1 % predicted ranged across control groups from 65.8% to 94.76% | Mean FEV1 % predicted in the intervention groups was
3.43% higher (‐0.61% lower to 7.47% higher) |
286 (4 studies) |
⊕⊝⊝⊝ very low1,3,4 | Fixed effect I2 = 2% | |
|
Average FVC value Follow‐up: 2 to 3 months |
See comment | Mean FVC in the intervention groups was
‐0.02 standard deviations lower (‐0.30 lower to 0.26 higher ) |
SMD ‐0.02 (‐0.30 to 0.26) | 197 (2 studies) |
⊕⊕⊝⊝ low2,4 | Fixed effect I2 = 0% As studies reported FVC on different scales, we pooled using SMD. No significant group difference in FVC between the 2 groups |
|
Quality of life: Marks Asthma Quality of Life Questionnaire Follow‐up: 3 months (higher score indicated greater impact on quality of life; scales from 1 to 7) |
See comment | See comment | 108 (1 study) | ⊕⊕⊝⊝ low4,5 | Only 1 trial contributed to this outcome, so we were unable to pool data | |
|
Asthma symptoms Follow‐up: 2 to 3 months (different self report questionnaires, lower scores mean fewer symptoms) |
Mean symptom score for control group ranged from 11.05 to 18.25 | Mean asthma symptoms in the intervention groups were
‐0.22 standard deviations lower (‐0.52 lower to 0.09 higher ) |
SMD ‐0.22 (‐0.52 to 0.09) | 166 (2 studies) | ⊕⊕⊝⊝ low2,4 | As studies reported asthma symptoms on different scales, we pooled using SMD. No significant group difference in asthma symptoms between the 2 groups |
|
Asthma control Follow‐up: 2 to 3 months (different instruments) |
See comment | Mean asthma control in the intervention groups was
0.29 standard deviations higher (0.01 higher to 0.58 higher ) |
SMD 0.29 (95% CI 0.01 to 0.58) | 194 (2 studies) |
⊕⊕⊝⊝ low2,6 | Fixed effect I2 = 0% As studies reported asthma control on different scales, we pooled using SMD |
|
Beta agonist use; puffs/d Follow‐up: 3 months |
See comment | See comment | 117 (1study) |
⊕⊕⊝⊝ low5,6 | Only one trial contributed to this outcome, so we were unable to pool data | |
|
Asthma distress; Asthma Bother Profile Follow‐up: 3 months |
See comment | See comment | 101 (1 study) |
⊕⊕⊝⊝ low4,5 | Only one trial contributed to this outcome, so we were unable to pool data | |
| *The basis for the assumed risk (e.g. median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; FEV1: Forced expiratory volume in one second; FVC: Forced vital capacity; SMD: Standardised mean difference. | ||||||
| GRADE Working Group grades of evidence. High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1Outcome assessors were not blinded in 3 of 4 studies.
2Outcome assessors were not blinded in 1 of 2 studies.
3One study was judged to be at high risk of bias for selective reporting.
4Confidence interval includes important benefit and no effect.
5Single study.
6Wide confidence interval.