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Comparing different reviews of rizatriptan

 

Clinical bottom line

Different systematic reviews of rizatriptan give much the same answer, despite somewhat different approaches.


References:

MJ Gawel et al . A systematic review of the use of triptans in acute migraine. Canadian Journal of Neurological Science 2001 28: 30-41.

MD Ferrari et al. Meta-analysis of rizatriptan efficacy in randomized controlled clinical trials. Cephalalgia 2001 21: 129-136.

Oldman AD , Smith LA, McQuay HJ, Moore RA. Rizatriptan for acute migraine (Cochrane Review). In: The Cochrane Library, Issue 3, 2001. Oxford: Update Software.

 

Having one good review of a topic is good, but having three is remarkable. We now have three migraine reviews that have examined the efficacy of rizatriptan 10 mg for the treatment of acute migraine. All have been abstracted by Bandolier , and the abstracts can be accessed from the links above.

How do they compare? The Table below gives the NNTs for four pain outcomes. All three reviews had two hour outcomes, two reported the outcome of sustained relief, and one sustained pain free.

Number needed to treat (95% confidence interval) for rizatriptan 10 mg

 

At 2 hours

Over 24 hours

 

Headache response

Pain free

Sustained response

Sustained pain free

Gawel et al

2.8 (2.6 to 3.2)

3.2 (2.9 to 3.5)

Ferrari et al

3.0 (2.8 to 3.4)

3.2 (3.0 to 3.5)

5.3 (4.6 to 6.2)

5.5 (4.9 to 6.4)

Oldman et al

2.7 (2.4 to 2.9)

3.1 (2.9 to 3.4)

5.6 (4.5 to 7.4)

Notes:

Gawel review used only published tablet data from 6 trials.

Ferrari review used data from tablets and wafers in 7 trials, but had individual data from trial records.

Oldman review combined published data on tablet and wafer from 7 trials, but probably used a different definition of intention to treat as numbers of patients differed.

The agreement was very close. What differences there were derived from two sources:

Rizatriptan 10 mg is available as a tablet and a wafer for buccal dissolution. two trials combined tablet and wafer data, while one used only tablets.

Then there is the issue of intention-to-treat. In migraine studies some patients can be randomised to treatment, but not have a migraine and not take the tablets. One review used only information from patients who did have a migraine attack, rather than all randomised.

Comment

Despite the nuances of methodology, the results were consistent. This gives us great confidence in the results, and demonstrates that here we have class 1 evidence.