Table 4.
Subgroup analyses by sex and age for intent to treat analysis of primary outcome of excellent recovery (total FAOS ≥450) in patients with acute ankle sprain randomised to usual care with physiotherapy or usual care alone
| Subgroup | No (%) of patients | Raw risk difference* (95% CI) | Adjusted risk difference* (95% CI)† | P value‡ | |
|---|---|---|---|---|---|
| Physiotherapy | Usual care | ||||
| Men | |||||
| Baseline | 0/107 (0) | 0/116 (0) | — | — | — |
| 1 month | 12/101 (12) | 24/112 (21) | −10% (−19% to 0%) | −7% (−20% to 6%) | 0.09 |
| 3 months | 46/93 (49) | 43/94 (46) | 4% (−11% to 18%) | 4% (−10% to 17%) | 0.60 |
| 6 months | 56/88 (64) | 54/86 (63) | 1% (−13% to 15%) | 2% (−12% to 15%) | 0.81 |
| Women | |||||
| Baseline | 0/146 (0) | 0/134 (0) | — | — | — |
| 1 month | 14/138 (10) | 10/127 (8) | 2% (−5% to 9%) | 2% (−5% to 8%) | 0.59 |
| 3 months | 52/136 (38) | 36/120 (30) | 8% (−3% to 20%) | 7% (−3% to 18%) | 0.25 |
| 6 months | 62/120 (52) | 66/109 (61) | −9% (−22% to 4%) | −10% (−23% to 2%) | 0.12 |
| Age ≤30 | |||||
| Baseline | 0/145 (0) | 0/150 (0) | — | — | — |
| 1 month | 18/139 (13) | 22/143 (15) | −2% (−11% to 6%) | −1% (−8% to 6%) | 0.47 |
| 3 months | 68/132 (52) | 47/122 (39) | 13% (1% to 5%) | 14% (3% to 25%) | 0.03** |
| 6 months | 75/118 (64) | 74/106 (70) | −6% (−19% to 6%) | −6% (−17% to 6%) | 0.37 |
| Age >30 | |||||
| Baseline | 0/108 (0) | 0/100 (0) | — | — | — |
| 1 month | 8/144 (8) | 12/96 (13) | −5% (−13% to 4%) | −3% (−14% to 8%) | 0.43 |
| 3 months | 30/97 (31) | 32/92 (35) | −4% (−17% to 10%) | −4% (−16% to 9%) | 0.52 |
| 6 months | 43/90 (48) | 46/89 (52) | −4% (−19% to 11%) | −6% (−19% to 6%) | 0.52 |
*Positive risk difference favours physiotherapy arm.
†Adjusted risk difference uses generalised linear model with binomial outcome and identity link to control for quarter of FAOS at baseline.
‡P value based on Mantel-Haenszel test stratified by quarter of FAOS at baseline.
§P value for subgroup by treatment interaction 0.14 at 1 month, 0.71 at 3 months, and 0.21 at 6 months.
¶P value for subgroup by treatment interaction 0.73 at 1 month, 0.05 at 3 months, and 0.93 at 6 months.
**Discrete treatment effect of P<0.05: these effects were not consistent across time points of measurement within the subgroups of age ≤30 and >30, and would not remain significant after any reasonable adjustment of multiple comparisons.