Persistent Poverty Is an Independent Risk Factor for Poor Clinical Outcomes in Colorectal Cancer: A State-Wide Analysis of 28,978 Patients

Background: The National Cancer Institute has identified living in an area of persistent poverty(PP) as a potential risk factor for cancer-related morbidity and mortality. We sought to assess the effect of PP on clinical outcomes in colon cancer(CC).

Methods:​ We identified all patients diagnosed with CC from the California Cancer Registry(2017-2020). We used multivariable regression models to compare mortality for CRC patients living in areas with different levels of PP (defined as ≥20% population living below the poverty line for >30 years). We also compared the differential impact of PP and current poverty (CP:defined as ≥20% of the census-tract population living below the poverty line) on cancer outcomes. ​

Results: 22,179 patients met inclusion criteria (33.8% from areas with some degree of PP). On univariate analysis, patients living in areas with more PP were younger, more likely to have more comorbidities, and more likely to use Medicaid as primary insurance. On multivariable analyses, living in an area with more PP was associated with higher overall mortality(OM), and higher disease-associated mortality(DAM)(Figure 1). Both CP and PP were independent and potentially additive risk factors for cancer-specific mortality (HR 1.15 for CP, 1.08 for PP, and 1.24 for CP and PP areas).

Conclusion: Living in an area with PP is associated with reduced access to care and higher OM and DAM in CC. Although CP is often measured and controlled for in analyses, PP may represent an independent and understudied risk factor that should be explored in efforts to improve health equity.