Stefan Elbers

100 Chapter 4 Self-Efficacy. For self-efficacy, the median follow-up time was 12 months. Six of eight studies were included in the meta-analysis (see Figure 7). We found an I 2 of 0%, indicating homogeneous results across studies. For five studies with endpoint data, there was a significant effect for self-efficacy at follow-up favouring the self-management group, SMD = −0.13 [−0.25, −0.02], z = 2.23, p = 0.03. This corresponds to a difference of 1.72 points on the PSEQ (0–60), using the standard deviation of the baseline control group of Nicholas et al. (2013) as reference. As the minimal important change of the PSEQ is estimated at 5.5 points (Chiarotto et al., 2016), this mean difference is clinically insignificant. Manning et al. (2014) did not find a difference at follow-up, SMD = −0.26 [−0.68, 0.16], z = 1.22, p = 0.22. Taal et al. (1993) reported a significant difference for self-efficacy favouring the self- management group (p < 0.05) with a positive change score of 0.17 for the self-management group and a change score of −0.06 for the control group at 13 months follow-up, whereas Hutting et al. (2015) did not find a difference at follow-up. Figure 7. Follow-up Comparison of Self-Management Intervention Versus Control on Self-Efficacy. Pain Intensity. Ten of the 13 studies were included in the meta-analysis (see Figure 8). The median follow-up time for all 13 studies was 12months.We decided to pool the results as the I 2 was 40% and the overlap of confidence intervals was sufficient. The pooled standardized mean difference of the nine studies with endpoint data was not statistically significant, SMD = −0.04 [−0.17, 0.09], z = 0.61, p = 0.54. This was similar for Manning et al. (2014): SMD = −0.35 [−0.77, 0.07], z = 1.62, p = 0.11. Taal et al. (1993) and Hutting et al. (2015) also did not report a significant difference at follow-up, but Dworkin et al. (2002) indicated that, at 12 months follow-up, pain intensity was lower for the experimental group, compared to the control group (p = 0.036).