Biomarkers of Individual Health Status Provide a Biological Signature of the Whole Person Living with Chronic Pain

Enormous investments in time and resources have been committed in the pursuit of reliable pain biomarkers and clinical endpoints to inform interventional investigations and patient care. Although there has been noteworthy progress, the field remains with limited tools to address the pressing needs of the clinical and research communities. Broadening the view and shifting the conceptual approach from a focus on pain mechanisms to include measures of biological individual health status might provide valuable information that has thus far been missed. Chronic pain is experienced within a complex and multifaceted array of life experiences. It is well established that numerous biopsychosocial factors are associated with variability in outcomes among individuals with chronic pain. Biomarkers that can capture the whole person milieu of an individual living with chronic pain would be highly informative. An overview of the theoretically grounded and evidence-based model, allostatic load, is provided. A summary of compelling evidence involving biomarkers of individual health status, measures of allostatic load, in chronic pain research follows. Next, possible complementary roles for biomarkers of individual health status in pain biomarker efforts are presented. Lastly, necessary next steps and future directions are identified. Although investigations are still in the early stages, biomarkers of individual health status offer promising potential to help (1) explain clinical heterogeneity, (2) identify those individuals more vulnerable to worse outcomes, and, with prospective validation, possibly (3) elucidate treatment response variability and (4) serve as clinical monitoring and surrogate endpoints.