The impact of social determinants of health on thyroid cancer mortality and time to treatment.

[BACKGROUND] Whereas racial disparities in thyroid cancer care are well established, the role of social determinants of health is less clear. We aimed to assess the individual and cumulative impact of social determinants of health on mortality and time to treatment among patients with thyroid cancer.

[METHODS] We collected social determinants of health data from thyroid cancer patients registered in the National Cancer Database from 2004 to 2017. We created a count variable for patients in the lowest quartile of each social determinant of health (ie, low income, low education, and no insurance). We assessed the association of social determinants of health with mortality and time to treatment and the association between cumulative social determinants of health count and time to treatment using Cox regression.

[RESULTS] Of the 142,024 patients we identified, patients with longer time to treatment had greater mortality compared to patients treated within 90 days (90-180 days, adjusted hazard ratio 1.21 (95% confidence interval 1.13-1.29, P < .001); >180 days, adjusted hazard ratio 1.57 (95% confidence interval 1.41-1.76, (P < .001). Compared to patients with no adverse social determinants of health, patients with 1, 2, or 3 adverse social determinants of health had a 10%, 12%, and 34%, respectively, higher likelihood of longer time to treatment (1 social determinant of health, hazard ratio 0.90, 95% confidence interval 0.89-0.92, P < .001; 2 social determinants of health, hazard ratio 0.88, 95% confidence interval 0.87-0.90, P < .001; 3 social determinants of health, hazard ratio 0.66, 95% confidence interval 0.62-0.71, P < .001 for all). On subgroup analysis by race, each adverse social determinant of health was associated with an increased likelihood of a longer time to treatment for Black and Hispanic patients (P < .05).

[CONCLUSION] A greater number of adverse social determinants of health leads to a higher likelihood of a longer time to treatment for patients with thyroid cancer, which, in turn, is associated with an increased risk for mortality.