Table 4.
Validation of pain intensity and physical function composite outcomes in randomized, placebo-controlled trials of duloxetine, gabapentin, and pregabalin for diabetic peripheral neuropathy and postherpetic neuralgia
| No. of Drug Responders (%) | No. of Placebo Responders (%) | Risk Ratio (95% CI) | Number Needed to Treat (95% CI)* | |
|---|---|---|---|---|
| Diabetic Peripheral Neuropathy | ||||
| Pregabalin (5 trials; Validation subsample, n=601) | ||||
| Composite 1 | 281 (71.0) | 112 (54.6) | 1.3 (1.1–1.6) | 6.1 (4.1–12.2) |
| Composite 4 | 251 (63.4) | 97 (47.3) | 1.3 (1.0–1.7) | 6.2 (4.1–13.0) |
| Composite 6 | 221 (55.8) | 79 (38.5) | 1.4 (1.1–1.9) | 5.8 (4.0–11.3) |
| Composite 10 | 197 (49.8) | 58 (28.3) | 1.8 (1.3–2.4) | 4.7 (3.4–7.5) |
| Gabapentin (2 trials; N=408) | ||||
| Composite 1 | 174 (69.6) | 85 (53.8) | 1.3 (1.1–1.6) | 6.3 (4.0–16.2) |
| Composite 4 | 158 (63.2) | 70 (44.3) | 1.4 (1.0–2.1) | Not calculated* |
| Composite 6 | 137 (54.8) | 63 (39.9) | 1.4 (1.0–1.9) | Not calculated* |
| Composite 10 | 112 (44.8) | 54 (34.2) | 1.3 (0.9–1.8) | Not calculated* |
| Duloxetine (2 trials; N=676) | ||||
| Composite 1 | 344 (75.9) | 130 (58.3) | 1.3 (1.1–1.6) | 5.7 (4.0–9.9) |
| Composite 4 | 323 (71.3) | 115 (51.6) | 1.4 (1.1–1.7) | 5.1 (3.7–8.4) |
| Composite 6 | 294 (64.9) | 95 (42.6) | 1.5 (1.2–1.9) | 4.5 (3.3–7.0) |
| Composite 10 | 260 (57.4) | 76 (34.1) | 1.7 (1.3–2.2) | 4.3 (3.3–6.5) |
| Postherpetic Neuralgia | ||||
| Pregabalin (4 trials; Validation subsample, n=474) | ||||
| Composite 1 | 172 (56.4) | 65 (38.5) | 1.5 (1.1–1.9) | 5.6 (3.7–11.7) |
| Composite 4 | 151 (49.5) | 54 (32.0) | 1.5 (1.2–2.0) | 5.7 (3.8–12.0) |
| Composite 6 | 135 (44.3) | 48 (28.4) | 1.6 (1.1–2.1) | 6.3 (4.1–14.7) |
| Composite 10 | 112 (36.7) | 27 (16.0) | 2.3 (1.5–3.5) | 4.8 (3.6–7.9) |
| Gabapentin (2 trials; N=563) | ||||
| Composite 1 | 248 (73.8) | 118 (52.0) | 1.4 (1.1–1.8) | 4.6 (3.4–7.3) |
| Composite 4 | 211 (62.8) | 93 (41.0) | 1.5 (1.2–2.0) | 4.6 (3.4–7.4) |
| Composite 6 | 182 (54.2) | 86 (37.9) | 1.4 (1.1–1.8) | 6.1 (4.1–12.7) |
| Composite 10 | 141 (42.0) | 41 (18.1) | 2.3 (1.6–3.3) | 4.2 (3.2–6.1) |
Note: Pain intensity measured with 0–10 numeric rating scale; physical function measured with SF-36 10-item subscale with scores ranging 0–100
Composite 1 responder = ≥30% reduction in pain intensity or ≥30% improvement in physical function
Composite 4 responder = ≥40% reduction in pain intensity or ≥40% improvement in physical function
Composite 6 responder = ≥50% reduction in pain intensity or ≥50% improvement in physical function
Composite 10 responder = ≥50% reduction in pain intensity, or ≥20% reduction in pain intensity and ≥30% improvement in physical function
NNT was not calculated when the 95% CI for the risk ratio contained 1, indicating no significant benefit of active drug treatment over placebo