Health inequalities and social determinants of health: The role of syndemics in rheumatic disease.

A syndemic is the co-existence of two or more health problems (including both social and biological features) that adversely influence each other with negative consequences on disease outcomes and perpetuation of inequalities. The syndemic approach can be applied to better understand the course of rheumatic musculoskeletal diseases (RMD) involving the study of adverse biological pathways and social determinants of health (SDH) all under the same framework. Identifying if a syndemic exists within RMDs may include investigating the synergic interactions between comorbidity (e.g., diabetes, obesity, chronic kidney diseases) and the concomitant of other adverse conditions (e.g., drug non-adherence, substance abuse), along with SDHs such as low household income, unemployment, low education, limited access to health care, as well as racial/ethnic discrimination. For decades, the understanding of RMDs progression has been based on causality, rather than investigating the kaleidoscopic web of connections that can potentially influence a disease course. The co-existence of health burdens in vulnerable populations, including those with RMD, specifically in certain socioeconomic groups, calls for new ways and strategies of thinking to improve our understanding of risk factors and co-morbidities to offer tailored interventions for clinical medicine and public health policy.