The role of the social determinants of health in outcomes of surgery for low back pain : a systematic review and narrative synthesis

Background context: Low back pain is a major cause of morbidity and disability worldwide and is responsible for vast societal impact. Rates of surgical intervention for lumbar spine disorders continue to rise but poor outcomes remain common. Understanding how the social determinants of health (SDH) influence spinal surgical outcomes stands to inform appropriately tailored care practices and lead to better patient outcomes. Purpose: To determine the relationships between the SDH and pain, opioid use, disability and work absenteeism following lumbar spine surgery. Study design: Systematic review and narrative synthesis. Methods: We searched Embase, the Cochrane Library, Medline, and Web of Science from inception to April 21, 2020. Studies eligible for inclusion involved participants receiving lumbar spine surgery and investigated the relationship between at least one SDH and post-surgical pain, opioid use, disability or work absenteeism. We evaluated the risk of bias of included studies and used the PROGRESS-Plus framework to organize a narrative synthesis of findings. Results: Relevant data was extracted from twenty-three studies involving 30,987 adults from 12 countries. A total of 107 relationships between the SDH and post-surgical outcomes were evaluated, 67 in multivariate analyses. Education was investigated in 23 analyses (14 studies): 70% revealed significant independent relationships between lower education and poorer outcomes. Socioeconomic status was investigated in nine analyses (four studies): 67% revealed independent relationships between lower socioeconomic status and poorer outcomes. Gender was investigated in 40 analyses (22 studies): indications that male versus female sex was associated with poorer outcomes were equivocal. Place of residence, race/ethnicity, and social capital were infrequently investigated. Conclusions: Low educational attainment and low-income status are clear independent contributors to poorer outcomes following lumbar spine surgery. Occupational factors and work context are likely to be influential. Further research is critical to guide best-practice spinal surgery through a health equity lens.