Summary of findings 2. Gabapentin compared with placebo for peripheral diabetic neuropathy: efficacy.

Gabapentin compared with placebo for peripheral diabetic neuropathy: efficacy
Patient or population: adults with peripheral diabetic neuropathy Settings: community Intervention: ≥ 1800 mg daily or gabapentin encarbil 1200 mg daily Comparison: placebo
Outcome	Probable outcome with gabapentin	Probable outcome with placebo	RR and NNT (95% CI)	Number of studies, participants	Certainty of the evidence (GRADE)	Comments
At least 50% pain intensity reduction	380 per 1000	230 per 1000	RR 1.7 (1.4 to 2.0) NNT 6.6 (5.0 to 9.7)	6 studies 1331 participants	Moderate	Downgraded because of issues around dosing, formulation, and imputation
Any definition of substantial benefit (at least 50% pain intensity reduction or PGIC very much improved)	380 per 1000	230 per 1000	RR 1.7 (1.4 to 2.0) NNT 6.6 (5.0 to 9.7)	6 studies 1331 participants	Moderate	Downgraded because of issues around dosing, formulation, and imputation
PGIC much or very much improved	500 per 1000	300 per 1000	RR 1.7 (1.4 to 2.0) NNT 4.9 (3.6 to 7.6)	5 studies 695 participants	Moderate	Downgraded because of issues around dosing, formulation, and imputation
Any definition of moderate benefit (at least 30% pain intensity reduction or PGIC much or very much improved)	520 per 1000	370 per 1000	RR 1.4 (1.3 to 1.6) NNT 6.6 (4.9 to 9.9)	7 studies 1439 participants	Moderate	Downgraded because of issues around dosing, formulation, and imputation
CI: confidence interval; IMMPACT: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials; NNT: number needed to treat for an additional beneficial outcome; RR: risk ratio
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.