The Role of Comorbidities in the Social Gradient in Cancer Survival in Europe

Abstract

Comorbidity is considered to be a prognostic factor in cancer outcomes. The presence of comorbidity can be influential at different points on the cancer pathway, from the time leading up to the diagnosis of cancer to treatment options and ultimate prognosis once cancer has been diagnosed. Cancer patients of lower social or socioeconomic position are more likely to be living with comorbidity than more affluent patients. This chapter aims to examine the role played by comorbidities in the social gradient in cancer survival that is often observed in Europe. It describes relationships between comorbidity and other factors associated with cancer survival, and discusses the findings of epidemiological studies within Europe that investigate comorbidity and social or socioeconomic inequalities in cancer outcomes.

A search of the scientific literature retrieved articles that investigated comorbidity as a factor in inequalities in outcomes among cancer patients in Denmark (n = 7), the Netherlands (n = 4), England (n = 2) or Sweden (n = 1). Many of these studies reported a reduction in inequalities in mortality or survival after adjustment for comorbidity, although the magnitude of the reduction varied between studies, as did approaches to measuring social position or comorbidity. Further analysis using methods such as causal mediation analysis would be required to quantify the causal effect of comorbidity on outcome inequalities.