2.8 Data synthesis
The association between PEs and the outcomes of interest was extracted as stated within the trials’ reports and considered as positive association, negative association or no association. Positive association was marked when higher PEs were associated with better outcomes or lower PEs were associated with lesser improvement. Negative association was marked when higher PEs were associated with lesser outcomes or lower PEs were associated with better outcomes. Non-significant associations were considered as no association. Also, a mutable associations was marked when the association between PEs and the outcomes were reported at different follow-up points, different groups and different interventions within the trial. Data regarding the association between PEs and the outcomes were extracted individually and reported for all of these mutable reported associations.
As the included studies featured a wide variety of interventions, as well as heterogeneity in expectations and outcomes measurement tools, it was difficult to conduct a quantitative synthesis. Therefore, a descriptive synthesis was carried out to qualitatively summarise the findings, which reported extracted data about the association between PEs and the outcomes of pain intensity, functional status and HRQOL. Results were stratified by the type of outcome (pain intensity, level of function (disability) or HRQOL) and the period of follow-up; short (≤ 6 weeks), medium (> 6 weeks - ≤ 6 months), and long (> 6 months).
Results