Social support as a moderator of healthcare adherence and distress in long-term hematopoietic cell transplantation survivors.

BACKGROUND: Treatment with hematopoietic cell transplantation (HCT) has potentially severe effects on physical and psychosocial functioning. Poor social support has been linked with physical morbidity and mortality as well as psychological distress in HCT survivors. This study tested a theory-driven hypothesis that social support buffers adverse effects of health stressors of comorbidities and graft-versus-host disease (cGVHD) on distress and adherence to recommended healthcare among long-term HCT survivors. METHODS: This cross-sectional study analyzed baseline data from a randomized controlled trial in adult survivors 3-18 years post-HCT. Data included medical records and patient-reported outcomes including cancer and treatment distress (CTXD), healthcare adherence (HCA), comorbidity index, cGVHD, ENRICHD Social Support Instrument (ESSI), Social Activity Log, and Health Self-Efficacy. We tested hypothesized models for HCA and CTXD using blocked hierarchical linear regressions. RESULTS: Among the 781 HCT survivors completing baseline assessment, 38% had > 3 comorbidities, 8% had moderate-severe cGVHD, 30% reported low social support, 30% reported elevated distress, and 49% reported low healthcare adherence. Social support and self-efficacy were directly related to both adherence and distress. Regression models supported the hypothesized moderated relationships for distress but not for healthcare adherence. CONCLUSIONS: The two tested models confirm that the health stressors of comorbidities and cGVHD are moderated by better social support and self-efficacy in their associations with lower distress but without moderating effects for healthcare adherence. IMPLICATIONS FOR CANCER SURVIVORS: Social support and self-efficacy confer protective benefits on healthcare adherence and psychological distress. Interventions are needed that focus on maintaining social networks or finding new networks if necessary. CLINICAL TRIAL REGISTRATION NUMBER: NCT00799461.