Table 3.
Patient and study characteristics for the placebo population in high placebo-response and low placebo-response studies
| Patient characteristics | DPN | PHN | |
|---|---|---|---|
|
| |||
| High placebo responsea (n=353) |
Low placebo responseb n=685) |
Low placebo responsec (n=476) |
|
| Age, mean (SD), y | 58.4 (10.1) | 59.3 (10.9) | 69.9 (10.4) |
| Female, n (%) | 190 (53.8) | 276 (40.3) | 231 (48.5) |
| Male, n (%) | 163 (46.2) | 409 (59.7) | 245 (51.5) |
| Baseline pain score, mean (SD) | 6.3 (1.5) | 6.4 (1.5) | 6.6 (1.5) |
| Duration of NeP, mean (SD), y | 3.8 (3.5) | 4.2 (3.2) | – |
| Duration of DPN, mean (SD), y | 4.3 (4.0) | 4.9 (3.7) | – |
| Duration of PHN, mean (SD), mo | – | – | 33.8 (36.9) |
| Study characteristics | |||
| Study duration, mean (SD), wk | 11.5 (3.7) | 9.1 (3.8) | 7.0 (3.3) |
| Total site recruitment | |||
| Patients per site, mean (SD) | 5.8 (4.2) | 3.8 (2.2) | 3.7 (2.2) |
| ≤5, n (%) | 217 (61.5) | 518 (75.6) | 367 (77.1) |
| 6–8, n (%) | 74 (21.0) | 157 (22.9) | 91 (19.1) |
| 9–11, n (%) | 30 (8.5) | 10 (1.5) | 18 (3.8) |
| ≥12, n (%) | 32 (9.1) | 0 | 0 |
| Discontinuations, n (%) | 63 (100) | 115 (100) | 100 (100) |
| Adverse event | 18 (28.6) | 34 (29.6) | 28 (28.0) |
| Lack of compliance | 0 | 7 (6.1) | 2 (2.0) |
| Lack of efficacy | 14 (22.2) | 51 (44.3) | 45 (45.0) |
| Other | 31 (49.2) | 23 (20.0) | 25 (25.0) |
| Pregabalin approval status,d n (%) | |||
| Preapproval | 0 | 467 (68.2) | 361 (75.8) |
| Postapproval | 353 (100) | 218 (31.8) | 115 (24.2) |
| Ratio of active to control,e n (%) | |||
| 1:1 | 0 | 287 (41.9) | 84 (17.6) |
| ≥2:1 | 353 (100) | 398 (58.1) | 392 (82.4) |
Notes: There were no high placebo-response studies in patients with PHN; Not all studies recorded duration of illness;
pooled placebo patients from studies A0081030, A0081071, and A0081081 (DPN);
pooled placebo patients from studies 1008-014,1008-029, 1008-040, 1008-131, 1008-149, 1008-155 (DPN), A0081060, and A0081163;
pooled placebo patients from studies 1008-030, 1008-045, 1008-127, 1008-155 (PHN), 1008-196, A0081004, and A0081081 (PHN);
pregabalin approval status at the commencement of the study;
ratio of the total number of patients receiving active treatment to patients receiving placebo.
Abbreviations: DPN, diabetic peripheral neuropathy; mo, months; NeP, diabetic neuropathic pain; PHN, postherpetic neuralgia; SD, standard deviation; wk, week; y, years.