3.1 Sample characteristics
In total, 229 surgery patients were recruited for the study, an estimated 10% retention rate was used as stop condition; 111 patients (48.5%) were allocated to the control group, whereas the remaining 118 patients (51.5%) were allocated to the intervention group. Out of 229 recruited, only 206 patients provided their demographic data and partially completed the baseline measure (control group: n = 111, 53.9%; intervention group: n = 95; 46.1%). Of these, 133 (64.6%) were treated at the thoracic surgery department and 73 (35.4%) at the abdominal and general surgery department. Most (n = 117; 56.8%) were female, while the rest (n = 89; 43.2%) identified as male during the study. Their age ranged from 20 to 85 years (M = 61.20, SD = 13.80). In terms of education, the majority of patients had finished lower (n = 64; 31.3%) or higher (n = 58; 28.2%) secondary education, followed by a bachelor’s degree or equivalent (n = 41; 19.9%), primary school or less (n = 27; 13.1%); master’s degree or equivalent (n = 11; 5.3%), and doctoral degree or equivalent (n = 5; 2.4%). The control and intervention group did not differ based on the department they were admitted to (χ2(1) = .606, p = .467), gender (χ2(1) = .305, p = .672), education (U = 5124.50, Z = -0.14, p = .888), nor age (t(204) = 0.29, p = .770, d = .04), providing support for demographic equivalence of the two groups.
179 surgery patients (86.9% of those who completed the baseline measure) at least partly filled out the post-intervention measure, 100 from the control group (55.9%) and 79 from the intervention group (44.1%). Those who filled out the T2 measure and those who dropped out did not differ in terms of their group (χ2(1) = 2.16, p = .153), gender (χ2(1) = 0.08, p = .837), education (U = 2374.50, Z = -0.15, p = .881), and age (t(204) = -0.43, p = .669), indicating the absence of selective dropout based on individuals’ group allocation and demographic variables. However, those who dropped out and those who did not differed in terms of the department they were admitted to (χ2(1) = 5.50, p = .029); specifically, while only 9.0% (n = 12) of thoracic surgery patients discontinued their participation, this was the case for 20.5% (n = 15) of abdominal and general surgery patients. The flow chart of participants can be seen in Fig. 3 below.
3.2. Descriptive statistics and bivariate associations
We first calculated basic descriptive statistics and bivariate associations for the whole sample, regardless of individuals' group allocation. The results are displayed in Table 1 below.
Table 1
Descriptive statistics and bivariate associations
| N | M | SD | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
1. Gender | 206 | 1.43 | 0.50 | - | | | | | | | | | | | |
2. Age | 206 | 61.20 | 13.80 | .11 | - | | | | | | | | | | |
3. Education | 206 | 2.81 | 1.20 | − .11 | − .26*** | - | | | | | | | | | |
4. Department | 206 | 1.35 | 0.48 | .11 | − .17* | .15* | - | | | | | | | | |
5. Acceptance of robots | 172 | 0.72 | 0.39 | .05 | − .07 | .13 | .15 | (.89) | | | | | | | |
6. Patient engagement (T1) | 198 | 4.31 | 0.59 | .14 | − .05 | .08 | .19** | .15 | (.91) | | | | | | |
7. Patient engagement (T2) | 174 | 4.26 | 0.59 | .15* | − .09 | .03 | − .08 | .00 | .30*** | (.93) | | | | | |
8. Perceived quality of care (T1) | 195 | 6.30 | 0.95 | .01 | .06 | .02 | − .03 | − .03 | .25*** | .08 | (.82) | | | | |
9. Perceived quality of care (T2) | 177 | 5.91 | 1.28 | .03 | .01 | .01 | − .29*** | − .06 | − .03 | .45*** | .14 | (.90) | | | |
10. Health-related quality of life (T1) | 206 | 2.67 | 0.30 | .00 | − .15* | .15* | .06 | − .01 | .33*** | .29*** | .12 | .07 | (.67) | | |
11. Health-related quality of life (T2) | 172 | 2.67 | 0.33 | − .01 | − .06 | .08 | − .24*** | − .08 | .11 | .34*** | .11 | .35*** | .48*** | (.76) | |
12. Self-rated health (T1) | 206 | 68.50 | 17.95 | .08 | − .19** | .11 | .03 | .01 | .39*** | .34*** | .10 | .15* | .39*** | .23** | - |
13. Self-rated health (T2) | 172 | 72.12 | 19.00 | .09 | − .07 | .07 | − .14 | .07 | .24** | .39*** | − .02 | .30*** | .31*** | .42*** | .38*** |
Notes. Gender: 1 = Female, 2 = Male. Department: 1 = Thoracic surgery, 2 = Abdominal and general surgery. Cases were excluded pairwise. * p < .050, ** p < .010, *** p < .001. |
3.3. Effects on patient engagement and perceived quality of care
Next, we investigated the changes in patient health engagement and perceived quality of medical care from baseline (T1) to post-intervention (T2) within each group and compared the changes between groups. The results of these analyses are displayed in Table 2.
Table 2
Patient engagement and perceived quality of care: Changes from baseline to post-intervention in the control and intervention group
| Baseline (T1) | Post-intervention (T2) | Comparison |
| M | SD | M | SD | |
Patient engagement | | | | | |
Control group (N = 95) | 4.31 | 0.63 | 4.20 | 0.67 | t(94) = -1.39, p = .167, d = − .14 |
Intervention group (N = 79) | 4.32 | 0.54 | 4.34 | 0.47 | t(78) = 0.31, p = .759, d = .04 |
Perceived quality of care | | | | | |
Control group (N = 97) | 6.33 | 0.92 | 5.89 | 1.30 | t(96) = -2.86, p = .005**, d = − .29 |
Intervention group (N = 77) | 6.36 | 0.93 | 5.93 | 1.29 | t(76) = -2.58, p = .012*, d = − .29 |
Notes. * p < .050, ** p < .010. |
The results related to patient engagement showed a decrease in the control group, whereas the intervention group experienced a slight increase in patient engagement. However, the changes were not statistically significant in either of the two groups. Furthermore, we did not observe a statistically significant interaction, demonstrating that the changes in the intervention group were not statistically significantly different from changes observed in the control group (F(1, 172) = 1.55, p = .215, ηp2 = .01). Moreover, our results showed that the perceived quality of care decreased statistically significantly from baseline to post-intervention in both control and intervention group. The trends of change were similar in both groups (F(1, 172) = .002, p = .966, ηp2 = .00).
3.4. Effects on health-related quality of life
Next, we investigated the changes in health-related quality of life from baseline (T1) to post-intervention (T2). The results of these analyses are displayed in Table 3.
Table 3
Health-related quality of life: Changes from baseline to post-intervention in the control and intervention group
| Baseline (T1) | Post-intervention (T2) | Comparison |
| M | SD | M | SD | |
Mobility | | | | | |
Control group (N = 95) | 2.69 | 0.46 | 2.69 | 0.46 | t(94) = 0.00, p = 1.000, d = .00 |
Intervention group (N = 77) | 2.70 | 0.46 | 2.74 | 0.47 | t(76) = 0.62, p = .535, d = .07 |
Self-care | | | | | |
Control group (N = 95) | 2.91 | 0.29 | 2.76 | 0.43 | t(94) = -3.73, p < .001***, d = − .38 |
Intervention group (N = 77) | 2.94 | 0.25 | 2.84 | 0.40 | t(76) = -2.16, p = .034*, d = − .25 |
Usual activities | | | | | |
Control group (N = 95) | 2.64 | 0.50 | 2.58 | 0.50 | t(94) = -1.10, p = .276, d = − .11 |
Intervention group (N = 78) | 2.60 | 0.52 | 2.64 | 0.48 | t(77) = 0.60, p = .552, d = .07 |
Pain/discomfort | | | | | |
Control group (N = 95) | 2.44 | 0.52 | 2.40 | 0.49 | t(94) = -0.65, p = .519, d = − .07 |
Intervention group (N = 77) | 2.36 | 0.48 | 2.51 | 0.50 | t(76) = 2.36, p = .021*, d = .27 |
Anxiety/depression | | | | | |
Control group (N = 95) | 2.61 | 0.55 | 2.78 | 0.42 | t(94) = 3.62, p < .001***, d = .37 |
Intervention group (N = 78) | 2.63 | 0.51 | 2.76 | 0.43 | t(77) = 2.00, p = .049*, d = .23 |
Whole scale (excluding VAS) | | | | | |
Control group (N = 95) | 2.66 | 0.31 | 2.64 | 0.34 | t(94) = -0.51, p = .610, d = − .05 |
Intervention group (N = 77) | 2.65 | 0.30 | 2.70 | 0.32 | t(76) = 1.31, p = .195, d = .15 |
Self-rated health (VAS) | | | | | |
Control group (N = 95) | 68.05 | 17.91 | 71.31 | 20.36 | t(94) = 1.52, p = .131, d = .16 |
Intervention group (N = 77) | 69.42 | 18.57 | 73.12 | 17.25 | t(76) = 1.58, p = .118, d = .18 |
The results showed that mobility, as one aspect of health-related quality of life, slightly increased in the intervention group, whereas it remained about the same in the control group; however, the changes were not statistically significant in either of the two groups. Similarly, we did not find significantly different patterns of change between the two groups (F(1, 170) = 0.23, p = .629, ηp2 = .00). Next, quality of life related to self-care decreased in both groups, but the change from T1 to T2 was significant only in the control group. The interaction was not statistically significant (F(1, 170) = 0.95, p = .332, ηp2 = .01). Quality of life related to usual activities slightly decreased in the control group and slightly increased in the intervention group, but the changes were not statistically significant. The interaction was also not statistically significant (F(1, 171) = 1.39, p = .240, ηp2 = .01), implying that the trends of change were relatively similar. Issues related to pain and discomfort increased in the control group, while they decreased in the intervention group, with the latter change being statistically significant. Moreover, the interaction was statistically significant as well, demonstrating different patterns of change between the two groups (F(1, 170) = 4.17, p = .043*, ηp2 = .02). Issues related to anxiety and depression decreased in both groups from baseline to post-intervention; the changes were statistically significant in both groups. However, the patterns of change were similar in both groups (F(1, 171) = 0.27, p = .605, ηp2 = .00).
When we look at the results pertaining to the whole scale, we can notice that the score, interpreted as health-related quality of life, decreased in the control group, whereas it increased in the intervention group. None of the changes were statistically significant, and the interaction was not statistically significant as well (F(1, 170) = 1.76, p = .186, ηp2 = .01). Lastly, self-rated health, measured with the VAS scale, slightly increased in both groups, but the changes were not statistically significant. Moreover, there was no interaction between groups (F(1, 170) = 0.02, p = .888, ηp2 = .00).
3.5. Exploration of variables that moderate the effects of the intervention on the selected outcomes
We first explored the potential moderators of the effects of the intervention on patient health engagement. We found that gender (b = .21, SE = .21, p = .335), age (b = .01, SE = .01, p = .334), and education (b = .07, SE = .09, p = .423) were not significant moderators, whereas individuals' department (b = .64, SE = .22, p = .004**) and willingness to use the robot (b = .57, SE = .27, p = .039*) were. Specifically, in the case of thoracic surgery departments, the change in patient health engagement from baseline to post-intervention was similar in both groups (control and intervention; b = − .06, SE = .12, p = .594). On the other hand, for abdominal and general surgery patients, the negative change from baseline to post-intervention was statistically significantly larger in the control group compared to the intervention group (b = .58, SE = .18, p = .002**). This significant interaction is visualized in Fig. 4.
Moreover, patients with low acceptance of socially assistive robots (b = − .08, SE = .15, p = .595) exhibited a slightly higher change in patient engagement if they were in the control group than the intervention group, but the difference was not statistically significant. On the other hand, patients with high acceptance of socially assistive robots (b = .30, SE = .13, p = .022*) exhibited a statistically significant higher change in patient engagement if they were in the intervention group, compared to the control group. This significant interaction is visualized in Fig. 3.
Similarly, we explored the potential moderators of the effects of the intervention on the perceived quality of medical care. We found that gender (b = .70, SE = .46, p = .129), age (b = .00, SE = .02, p = .827), education (b = .02, SE = .20, p = .915), department (b = .62, SE = .47, p = .184), and willingness to use the robot (b = .96, SE = .61, p = .114) were not significant moderators.
Lastly, we explored the potential moderators of the effects of the intervention on health-related quality of life (separately for the whole scale excluding VAS and the VAS score). For the whole scale, we found that gender (b = .04, SE = .10, p = .664), age (b = .00, SE = .00, p = .837), education (b = − .05, SE = .04, p = .285), department (b = .14, SE = .10, p = .172), willingness to use the robot (b = .09, SE = .13, p = .505), change in patient health engagement (b = .06, SE = .08, p = .425), and change in the perceived quality of medical care (b = − .02, SE = .03, p = .469) were not significant moderators. Similarly, gender (b = 1.91, SE = 6.43, p = .767), age (b = .13, SE = .24, p = .600), education (b = -3.35, SE = 2.76, p = .226), department (b = 1.82, SE = 6.81, p = .790), willingness to use the robot (b = -2.76, SE = 8.31, p = .741), change in patient health engagement (b = -1.12, SE = 4.91, p = .820), and change in the perceived quality of medical care (b = -2.31, SE = 2.17, p = .289) were not significant moderators of VAS scores. Simple bivariate correlations between changes in patient health engagement, perceived quality of care, and health-related quality of life may be found in the Appendix.