Emotional Distress Statistically Accounts for the Cross-Sectional Association Between Spiritual Well-Being and Global Quality of Life in Patients with Cancer

Background and Objectives: Spiritual well-being is consistently associated with better quality of life in oncology, but the pathways involved are disputed. Two competing accounts exist: spiritual well-being may buffer patients against the impact of physical symptoms, or it may act mainly through emotional distress. We examined whether cross-sectional data from a Romanian cancer cohort are compatible with either account. Materials and Methods: In this single-centre cross-sectional study, 175 adults with cancer completed the FACIT-Sp-12, the Religious Commitment Inventory-10, the EORTC QLQ-C30 and the Hospital Anxiety and Depression Scale; the FACIT-Sp-12, QLQ-C30 and HADS were administered in locally adapted formats that deviate from the validated instruments, so all findings pertain to these adapted versions. Patients were grouped by tertile of FACIT-Sp-12 score. The primary outcome was global health status/quality of life. Multivariable linear regression with heteroscedasticity-consistent standard errors, prespecified bootstrapped mediation analyses (interpreted as cross-sectional statistical decompositions), a multiplicative moderation test, restricted cubic splines and nine prespecified sensitivity analyses were performed. Results: Patients were 62.2 ± 13.1 years old, 65.1% had advanced disease and 51.4% screened positive for clinically significant distress (HADS-Anxiety or HADS-Depression ≥ 8). Global quality of life rose monotonically across spiritual well-being tertiles (53.8 ± 28.0, 65.9 ± 22.3 and 74.5 ± 23.1 points; p < 0.001), with an adjusted high-versus-low difference of 14.9 (4.3 to 25.5) points. In the prespecified primary model, each standard deviation of spiritual well-being was associated with 7.15 (3.45 to 10.86) points of global quality of life. In separate prespecified single-mediator models, the indirect associations through HADS-anxiety (4.21 points, 95% CI 1.89 to 6.86) and HADS-depression (3.03 points, 95% CI 1.17 to 5.43) were both statistically significant (bootstrapped p < 0.001); these cross-sectional decompositions are equally compatible with reverse, bidirectional or common-cause structures. No statistically detectable spiritual well-being × symptom burden interaction was found (β = −1.198, 95% CI −6.355 to 3.959; p = 0.649), but the confidence interval included clinically relevant effect modification in either direction, and there was no evidence of departure from linearity in the dose–response relationship (p for non-linearity = 0.510). Coefficients for the peace subscale were consistently larger than those for faith, although the subscales were modelled separately. Conclusions: Higher scores on the adapted FACIT-Sp-12 were cross-sectionally associated with better global quality of life and lower emotional distress. Anxiety and depression statistically accounted for part of this association, but temporal ordering and causality cannot be determined from these data, and the interaction analysis was too imprecise to support or exclude buffering. Routine assessment of spiritual and emotional concerns alongside symptom control is supported; whether interventions that increase spiritual well-being improve quality of life requires longitudinal and interventional study using the validated instrument formats.