Table 3. PACE-UP and PACE-Lift studies: Imputation analyses for step counts at 3 years (PACE-UP) and 4 years (PACE-Lift).
| Imputation models | PACE-UP study | PACE-Lift study | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Postal versus Control | Nurse versus Control | Intervention versus Control | ||||||||||||
| N | Effect | (95% CI) |
p-value |
Effect | (95% CI) | p-value | N | Effect | (95% CI) | p-value | ||||
| All participants with follow-up data | 681 | 627 | (198–1,056) |
0.004 |
670 | (237–1,102) | 0.002 | 225 | 407 | (−177–992) | 0.17 | |||
| Imputed using treatment group, baseline steps, gender, age, practice, month baseline accelerometry | 1,023 | 597 | (174–1,020) |
0.006 |
679 | (268–1,089) | 0.001 | 298 | 429 | (−152–1,010) | 0.15 | |||
| Imputed using treatment group, baseline steps, gender, age, practice, month baseline accelerometry, baseline deprivation, baseline self-reported pain, and baseline body fat mass† | 996 | 634 | (211–1,057) |
0.003 |
735 | (293–1,178) | 0.001 | 292 | 437 | (−154–1,028) | 0.15 | |||
| Imputed using treatment group, baseline steps, gender, age, practice, month baseline accelerometry, and 12-month steps†† | 965 | 625 | (217–1,033) |
0.003 |
683 | (270–1,095) | 0.001 | 280 | 367 | (−181–916) | 0.19 | |||
Multiple imputations were carried out using the Stata commands mi impute followed by mi estimate in Stata V12, with three different sets of covariates, as listed in the table. The results shown are the change in each intervention group relative to the change in their control group. The effect estimates, 95% confidence intervals, and p-values were obtained from the model output.
†Imputed values were only available for 996 (PACE-UP) and 292 (PACE-Lift) when including baseline deprivation in the model (PACE-UP NS-SEC and PACE-Lift Index of Multiple Deprivation).
††Imputed values only available for 965 (PACE-UP) and 280 (PACE-Lift) when including 12-month steps in the model.
Abbreviations: NS-SEC, National Statistics Socio-economic classification; PACE-Lift, Pedometer Accelerometer Consultation Evaluation-Lift; PACE-UP, Pedometer And Consultation Evaluation-UP.