Gabapentin compared with placebo for fibromyalgia

Patient or population: adults with fibromyalgia

Settings: community

Intervention: gabapentin

Comparison: placebo

30% pain reduction at 12 weeks

Not calculated

1 study, 150 participants

very low

One included study of fewer than 200 participants; LOCF imputation.

Downgraded three levels because of small numbers and study limitations

50% pain reduction at 12 weeks

‐

‐

very low

Outcome not reported

PGIC ‐ any category of "better"

at 12 weeks

Not calculated

1 study, 150 participants

very low

One included study of fewer than 200 participants; LOCF imputation;

non‐standard outcome ‐ usually top two categories of better, not top three, used

Downgraded three levels because of small numbers and study limitations

Withdrawals due to adverse events

Not calculated

1 study, 150 participants

very low

One included study of fewer than 200 participants; few events

Downgraded three levels because of small numbers

Serious adverse events

‐

1 study, 150 participants

very low

‐

Deaths

‐

1 study, 150 participants

very low

‐

CI: Confidence interval; LOCF: last observation carried forward; PGIC: Patient Global Impression of Change

Descriptors for levels of evidence (EPOC 2015):
High quality: This research provides a very good indication of the likely effect. The likelihood that the effect will be substantially different^† is low.
Moderate quality: This research provides a good indication of the likely effect. The likelihood that the effect will be substantially different^† is moderate.
Low quality: This research provides some indication of the likely effect. However, the likelihood that it will be substantially different^† is high.
Very low quality: This research does not provide a reliable indication of the likely effect. The likelihood that the effect will be substantially different^† is very high.

^† Substantially different: a large enough difference that it might affect a decision.