Summary of findings for the main comparison.
Summary of findings ‐ Carbamazepine compared with phenobarbitone for epilepsy (primary outcome)
| Carbamazepine compared with phenobarbitone for epilepsy | ||||||
|
Patient or population: adults and children with newly onset partial or generalised epilepsy Settings: outpatients Intervention: carbamazepine Comparison: phenobarbitone | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI)¹ | No of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Phenobarbitone | Carbamazepine | |||||
|
Time to withdrawal of allocated treatment ‐ all participants, stratified by epilepsy type Range of follow‐up (all participants): 0 to 4653 days |
390 per 1000 | 281 per 1000 (224 to 350) | HR 1.50 (1.15 to 1.95) | 676 (4 studies) |
⊕⊕⊝⊝ low2,3 | HR > 1 indicates a clinical advantage for carbamazepine |
|
Time to withdrawal of allocated treatment Subgroup: generalised onset seizures Range of follow‐up (all participants): 0 to 4653 days |
286 per 1000 | 197 per 1000 (110 to 340) | HR 1.53 (0.81 to 2.88) | 156 (3 studies) |
⊕⊕⊝⊝ low2,3 | HR > 1 indicates a clinical advantage for carbamazepine |
|
Time to withdrawal of allocated treatment Subgroup: partial onset seizures Range of follow‐up (all participants): 0 to 4272 days |
420 per 1000 | 307 per 1000 (239 to 385) | HR 1.49 (1.12 to 2.00) | 520 (4 studies) |
⊕⊕⊝⊝ low2,3 | HR > 1 indicates a clinical advantage for carbamazepine |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The assumed risk is calculated as the event rate in the phenobarbitone treatment group. The corresponding risk in the carbamazepine treatment group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). The corresponding risk is calculated as the assumed risk x the relative risk of the intervention where relative risk = (1 ‐ exp(HR x ln(1 ‐ assumed risk)) )/assumed risk. CI: confidence interval; RR: risk ratio; HR: hazard ratio; exp: exponential. | ||||||
| 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. | ||||||
1Pooled HR for all participants adjusted for seizure type. 2There was high risk of bias for at least one element of three studies included in the analysis; de Silva 1996 and Heller 1995 were open‐label, and the lack of masking may have influenced the withdrawal rates in the study. Placencia 1993 did not adequately conceal allocation for all participants, which may have influenced the withdrawal rates in the study. There were inconsistencies in Placencia 1993 between published data and IPD, which the authors could not resolve. 3Substantial heterogeneity was present between studies; sensitivity analyses showed that Placencia 1993 contributed the largest amount of variability to analysis.