Summary of findings for the main comparison. Surgery compared with no surgery for obesity.
Surgery compared with no surgery for obesity | ||||||
Patient or population: participants with obesity Settings: any Intervention: surgery Comparison: no surgery | ||||||
Outcomes | No surgery | Surgery | Relative effect (95% CI) | No of participants (studies) | Quality of the evidence (GRADE) | Comments |
BMI at study end [kg/m²] Follow‐up: 12 to 24 months | See comment | See comment | Not estimablea | 582 (5) | ⊕⊕⊕⊝ moderateb | The direction of the effect was consistently in favour of surgery |
Health‐related quality of life Short Form Health Survey (SF‐36) Follow‐up: mean 2 years | See comment | See comment | Not estimablea | 140 (2) | ⊕⊕⊕⊝ moderatec | Improvements were seen in both studies for some aspects of health‐related quality of life but not others |
Comobidities: diabetes Different definitions used Follow‐up: 12 to 24 months | See comment | See comment | Not estimablea | 442 (5) | ⊕⊕⊕⊝ moderateb | More people experienced remission of disease following surgery |
Mortality Follow‐up: 12 to 24 months |
See comment | See comment | Not estimablea | 478 (5) |
⊕⊕⊕⊝ moderated | 5 of 7 studies reported data: no deaths occurred |
Serious adverse events (SAEs) [%] Follow‐up: 12 to 24 months |
See comment | See comment | Not estimablea | 438 (4) |
⊕⊝⊝⊝ very lowe | 4 of 7 studies reported data: SAEs ranged from 0% to 37% in the surgery group and from 0% to 25% in the no surgery group |
Reoperations [%] Follow‐up: 12 to 24 months |
See comment | See comment | Not estimablea | 470 (5) |
⊕⊝⊝⊝ very lowe | 5 studies reported data: 2% to 13% of participants in the surgery group underwent reoperations |
*The basis for the assumed risk (e.g. the 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). BMI: body mass index; CI: confidence interval | ||||||
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. |
aStudies could not be pooled due to differences in participants, interventions (types of surgery), and comparators bDowngraded by one level because allocation concealment was unclear in most studies. Blinding was not possible in trials of surgery versus no surgery, however this was judged to have little impact on measures of weight/BMI cDowngraded by one level because allocation concealment was unclear in one trial. No or unclear blinding of outcome assessors could affect subjective outcomes dDowngraded by one level because only 5 of 7 studies provided data eDowngraded by three levels because of inconsistent reporting, risk of bias and imprecision