Table 3.
Calculation of effect sizes for immediate and short term pain and disability outcome measures in people with osteoarthritis randomised to paracetamol or placebo
| Outcome scale | Range | Mean (SD or SE), extracted | Mean (SD), converted* | No of patients | MD (95% CI) | Analytical method* | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Paracetamol | Placebo | Paracetamol | Placebo | Paracetamol | Placebo | |||||||
| Pain/immediate term | ||||||||||||
| Zoppi, 199544 | VAS | 0-100 | −20.0† (21.5‡) | −10. 8† (18‡) | −20.0 (21.5) | −10.8 (18.0) | 28 | 28 | −9.2 (−19.6 to 1.2) | CS | ||
| Case, 200346 | WOMAC pain (VAS) | 0-500 | −4.7 (58.4) | −1.5 (52.3) | −0.9 (11.7) | −0.3 (10.5) | 27 | 26 | −0.6 (−6.6 to 5.3) | CS | ||
| Golden, 200447 | Pain on WB | 0-4 | −0.9† (18.1§) | −0.7† (16.5§) | −22.2 (18.1) | −18.0 (16.5) | 145 | 149 | −4.2 (−8.2 to −0.2) | CS | ||
| Miceli-Richard, 200448 | VAS | 0-100 | −16.0 (21.0) | −15.0 (21) | −16.0 (21.0) | −15.0 (21.0) | 385 | 356 | −1.0 (−4.0 to 2.0) | CS | ||
| Prior, 201454 | WOMAC pain (VAS) | 0-100 | −26.4 (1.5) | −20.5 (1.5) | −26.4 (24.2¶) | −20.5 (24.5¶) | 267 | 275 | −5.9 (−10.0 to −1.8) | CS | ||
| Pain/short term | ||||||||||||
| Case, 200346 | WOMAC pain (VAS) | 0-500 | −23.8 (83.2) | −15.3 (98.7) | −4.8 (16.6) | −3.1 (19.7) | 22 | 19 | −1.7 (−12.8 to 9.4) | CS | ||
| Miceli-Richard, 200448 | VAS | 0-100 | NA** | NA** | NA** | NA** | 298 | 262 | −0.8 (−4.4 to 2.8) | ANCOVA | ||
| Pincus, 2004a49 | MDHAQ pain (VAS) | 0-100 | −17.4 (2.0) | −10.5 (1.9) | −17.4 (26.0¶) | −10.5 (25.2¶) | 171 | 172 | −6.9 (−12.3 to −1.5) | CS | ||
| Pincus, 2004b49 | MDHAQ pain (VAS) | 0-100 | −13.8 (1.7) | −7.6 (2.0) | −13.8 (23.7¶) | −7.6 (26.9¶) | 185 | 182 | −6.2 (−11.4 to −1.0) | CS | ||
| Herrero-Beaumont, 200751 | WOMAC pain (LK3) | 0-20 | NA** | NA** | NA** | NA** | 108 | 104 | −2.5 (−7.7 to 2.7) | ANCOVA | ||
| Altman, 2007a50†† | WOMAC pain (VAS) | 0-100 | −26.5 (25.5) | −19.6 (22.5) | −26.5 (25.5) | −19.6 (22.5) | 160 | 83 | −6.9 (−13.4 to −0.4) | CS | ||
| Altman, 2007b50‡‡ | WOMAC pain (VAS) | 0-100 | −22.8 (21.6) | −19.6 (22.5) | −22.8 (21.6) | −19.6 (22.5) | 158 | 82 | −3.2 (−9.0 to 2.6) | CS | ||
| Prior, 201454 | WOMAC pain (VAS) | 0-100 | −30.0 (1.6) | −25.8 ( 1.5) | −30.0 (20.9¶) | −25.8 (20.3¶) | 177 | 172 | −4.2 (−8.5 to 0.1) | CS | ||
| Disability/immediate term | ||||||||||||
| Case, 200346 | WOMAC function | 0-1700 | 7.8 (123.1) | −35.6 (129.9) | 0.5 (7.2) | −2.1 (7.6) | 27 | 26 | 2.6 (−1.5 to 6.6) | CS | ||
| Miceli-Richard, 200448 | WOMAC function | 0-100 | −8.0 (12.0) | −7.0 (12.0) | −8.0 (12.0) | −7.0 (12.0) | 385 | 356 | −1.0 (−2.7 to 0.7) | CS | ||
| Prior, 201454 | WOMAC function | 0-100 | −23.1 (1.3) | −16.6 (1.2) | −23.1 (21.7¶) | −16.1 (19.9¶) | 267 | 275 | −6.5 (−10.0 to −3.0) | CS | ||
| Disability/short term | ||||||||||||
| Case, 200346 | WOMAC function | 0-1700 | −41.8 (205.6) | −85.6 (223.2) | −2.5 (12.1) | −5.0 (13.1) | 22 | 19 | 2.6 (−5.1 to 10.3) | CS | ||
| Miceli-Richard, 200448 | WOMAC function | 0-100 | −12.0 (17.0) | −12.0 (16.0) | −12.0 (17.0) | −12.0 (16.0) | 298 | 262 | 0.0 (−2.7 to 2.7) | CS | ||
| Pincus, 2004a49 | WOMAC total | 0-100 | −8.4 (1.5) | −4.8 (1.7) | −8.4 (19.9¶) | −4.8 (21.8¶) | 171 | 172 | −3.6 (−8.0 to 0.8) | CS | ||
| Pincus, 2004b49 | WOMAC total | 0-100 | −8.4 (1.3) | −4.6 (1.5) | −8.4 (17.7¶) | −4.6 (20.2¶) | 185 | 182 | −3.8 (−7.7 to 0.1) | CS | ||
| Herrero-Beaumont, 200751 | WOMAC function | 0-68 | NA** | NA** | NA** | NA** | 108 | 104 | −4.7 (−9.5 to −0.1) | ANCOVA | ||
| Altman, 2007a50†† | WOMAC function | 0-100 | −24.9 (24.6) | −17.8 (22.3) | −24.9 (24.6) | −17.8 (22.3) | 160 | 82 | −7.1 (−13.4 to −0.8) | CS | ||
| Altman, 2007b50‡‡ | WOMAC function | 0-100 | −18.8 (21.9) | −17.8 (22.3) | −18.8 (21.9) | −17.8 (22.3) | 158 | 82 | −1.0 (-6.9 to 4.9) | CS | ||
| Prior, 201454 | WOMAC function | 0-100 | −26.6 (1.5) | −21.3 (1.5) | −26.6 (20.0¶) | −21.3 (19.5¶) | 177 | 172 | −5.4 (−9.5 to −1.2) | CS | ||
MD=mean difference, SD=standard deviation, SE=standard error, VAS=visual analogue scale, LK3=Likert scale, CS=change score, ANCOVA=analysis of covariance, NA=not applicable, MDHAQ=multidimensional health assessment questionnaire, WOMAC=Western Ontario McMaster osteoarthritis index.
*Used to calculate treatment effect.
†Mean calculated from graphs.
‡SD from baseline.
§Average SD adopted from similar studies, Zoppi, Case, and Miceli-Richard.
¶SD calculated using SE and sample size.
**Weighted mean difference and 95% CI provided.
††Paracetamol (paracetamol extended release 1300 mg, 3 times daily, 3900 mg total) v placebo. Placebo sample size was divided by 2.
‡‡Paracetamol (paracetamol 650 mg, 3 times daily, 1950 mg total) v placebo. Placebo sample size was divided by 2.