Moderating effect of sense of coherence on the relationship between symptom distress and health-related quality of life in patients receiving cancer chemotherapy.

Purpose: This study is aimed at examining the buffering effect of sense of coherence (SOC) on symptom distress during cancer drug therapy, which thereby affects health-related quality of life (QoL), and obtaining suggestions for promoting supportive care.
Methods: We investigated health-related QoL (SF-8), symptom distress (using the Symptom Distress Scale (SDS)), and SOC (the SOC 13-item Scale) in 66 patients receiving adjuvant chemotherapy for non-small cell lung cancer. We employed descriptive statistics to seek the correlation of each variable; then, a hierarchical multiple regression analysis was conducted with SF-8 score as the dependent variable.
Results: Results showed that significant changes in bodily pain showed a buffering effect on the SDS and sense of comprehensibility (β = - 0.658, p < 0.01, β = - 0.319, p < 0.05), sense of manageability (β = - 0.658, p < 0.01, β = 0.398, p < 0.01), and meaningfulness (β = - 0.658, p < 0.01, β = - 0.257, p < 0.05). Significant changes in general health perception showed a buffering effect on the SDS and sense of manageability (β = - 0.406, p < 0.01, β = 0.329, p < 0.05). As a result of the simple inclination test, SOC proved to be effective under high levels of symptom distress; the buffering effect of sense of manageability was reversed regarding bodily pain; and when meaningfulness was lower, it had a positive effect on QoL.
Conclusion: This study revealed that SOC exerts a buffering effect in situations where symptoms are highly painful. It also revealed that the effect of SOC was reversed for bodily pain and that a high SOC had a negative effect on QoL.