The association between social vulnerability index and survival in older adults with gastrointestinal cancers - The CARE Registry.

[INTRODUCTION] Older adults represent a majority of gastrointestinal (GI) cancer cases. Social determinants of health, such as neighborhood-level social vulnerability index (SVI), are associated with frailty, a predictor of mortality. The association between social vulnerability and survival is understudied.

[MATERIALS AND METHODS] We evaluated 876 adults ≥60y with GI cancer enrolled in the Cancer & Aging Resilience Evaluation (CARE) Registry prior to chemotherapy. Exposure was the Center for Disease Control and Prevention's SVI in tertiles. SVI ranks census tracts between 0th and 100th percentile for lowest and highest vulnerability, respectively. Outcome was survival (enrollment to end of follow-up). Associations between SVI and survival were estimated using Cox proportional hazards models.

[RESULTS] Median age of patients was 69y, 58 % were male, 22 % were non-Hispanic Black, 30 % had colorectal, 29 % had pancreatic cancer, and 70 % had stage III/IV disease. About 44 % of participants died in median 17 months follow-up. Frailty status differed by SVI tertile (tertile 1: 26.8 %; tertile 2: 34.3 %; tertile 3: 43.4 %, p-value: <0.001). Adjusting for age, sex, and cancer type/stage, those living in neighborhoods in the highest SVI tertile had 6 % higher hazard of death (95 % confidence interval [CI]: 0.8, 1.4) and in the second-highest tertile had 8 % higher hazard of death (95 % CI: 0.9, 1.4) compared to those in the lowest tertile. This association may be driven by the SVI housing characteristics theme [tertile 2: hazard ratio (HR) 1.40 (95 % CI: 1.09, 1.79); tertile 3: HR 1.20 (95 % CI: 0.93, 1.55)].

[DISCUSSION] We did not find a statistically significant association between SVI and survival among older adults with GI cancers. Prior evidence of associations between SVI and overall area-level mortality may not reflect individual-level mortality specific to older adults. Prior evidence of associations between SVI and individual-level frailty among older adults with GI cancers suggests SVI may confer greater risk on development of frailty, which could indirectly impact survival. SVI of at-risk areas may need consideration when designing solutions to improve frailty among older adults with GI cancers, which could have a subsequent positive impact on mortality.