Summary of findings for the main comparison. Topiramate compared with carbamazepine for epilepsy (time to treatment failure).
| Topiramate compared with carbamazepine for epilepsy (time to treatment failure) | ||||||
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Population: adults and children with newly onset focal or generalised epilepsy Settings: outpatients Intervention: topiramate Comparison: carbamazepine | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Carbamazepine | Topiramate | |||||
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Time to treatment failure (any reason related to treatment) All participants ‐ adjusted by seizure type Range of follow‐up: 0 to 2420 days |
The median time to treatment failure was 1144 days in the carbamazepine group | The median time to treatment failure was 614 days (530 days shorter) in the topiramate group | HR 1.16 (0.97 to 1.38)a |
1129 (2 studies) |
⊕⊕⊕⊝ Moderateb | HR < 1 indicates a clinical advantage for topiramate Treatment failure due to lack of efficacy (HR 1.46, 95% CI 1.08 to 1.98, P = 0.01), occurred significantly earlier on topiramate compared to carbamazepine and there was no difference between the drugs for treatment failure due to adverse events (HR 1.02, 95% CI 0.82 to 1.27, P = 0.84) |
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Time to treatment failure (any reason related to treatment)Subgroup: focal onset seizures Range of follow‐up: 0 to 2420 days |
The median time to treatment failure was 1149 days in the carbamazepine group | The median time to treatment failure was 505 days (644 days shorter) in the topiramate group | HR 1.21 (1.01 to 1.46) |
937 (2 studies) |
⊕⊕⊕⊝ Moderateb | HR < 1 indicates a clinical advantage for topiramate Treatment failure due to lack of efficacy (HR 1.47, 95% CI 1.07 to 2.02, P = 0.02), occurred significantly earlier on topiramate compared to carbamazepine and there was no difference between the drugs for treatment failure due to adverse events (HR 1.08, 95% CI 0.85 to 1.36, P = 0.53) |
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Time to treatment failure (any reason related to treatment) Subgroup: generalised onset tonic‐clonic seizures or unclassified epilepsy Range of follow‐up: 0 to 1446 days |
The median time to treatment failure was 1056 days in the carbamazepine group | The median time to treatment failure was 1448 days (392 days longer) in the topiramate group | HR 0.88 (0.56 to 1.39) |
192 (2 studies) |
⊕⊕⊝⊝ Lowc, d | HR < 1 indicates a clinical advantage for topiramate There was also no statistically significant difference between drugs in treatment failure due to adverse events (HR 0.72, 95% CI 0.39 to 1.31, P = 0.28) or treatment failure due to lack of efficacy (HR 1.41, 95% CI 0.54 to 3.67, P = 0.48) |
| *Illustrative risks in the topiramate and carbamazepine groups are calculated at the median time to treatment failure (i.e. the time to 50% of participants failing or withdrawing from allocated treatment) within each group across all trials. The relative effect (pooled hazard ratio) shows the comparison of 'time to treatment failure' between the treatment groups. CI: confidence interval; HR: hazard ratio | ||||||
| GRADE Working Group grades of evidence High certainty: further research is very unlikely to change our confidence in the estimate of effect Moderate certainty: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate Low certainty: 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 certainty: we are very uncertain about the estimate | ||||||
aPooled HR for all participants adjusted for seizure type. bDowngraded once for risk of bias; the larger of the two studies was open‐label (SANAD A 2007), and may have influenced the withdrawal rates of the trial. cDowngraded once for imprecision and applicability; limited information on generalised seizure types and most participants do not have a classified seizure type in this subgroup so the interpretation of this seizure type is unclear.