Social Determinants of Health Influence Early Outcomes Following Lumbar Spine Surgery

DISCUSSION

Our study identified several SDoH that may be correlated with favorable outcomes. When controlling for age, ASA classification, and surgery type, we found that of the SDoH examined, financial resources and strong support systems (ie, currently married or having a life partner) appeared to be correlated with improved postoperative outcomes. Patients with an HHI above the state median were more likely to be discharged to an SNF, while patients with financial strain were more likely to have a longer LOS. Conversely, married patients or those with a life partner were less likely to be discharged to an SNF and had a shorter LOS. Church attendance was the only SDoH associated with a decreased likelihood of a 30-day ED return. Based on these results, patients at risk for suboptimal outcomes appear to be those with lower financial resources, less in-home support, and lower social connectivity (ie, do not attend church). These factors should be considered when preoperatively assessing patient risk profiles; triaging these patients to appropriate support services may improve surgical outcomes.

While a relative paucity of literature evaluating the impact of SDoH on spine surgery outcomes exists, the number of studies evaluating the prognostic value of SDoH has increased. In a 2021 retrospective cohort study, Khalid et al compared 8,280 patients with an SDoH disparity to those without and found that patients undergoing lumbar fusion surgery with at least one SDoH disparity had a 1.7 times increased risk of developing pseudoarthrosis or any other complication.¹¹ However, Khalid et al found no difference in revision surgery or 30-day readmission as in our current study. In another study assessing the relationship between SDoH and readmissions, Mohanty et al evaluated 2,830 patients undergoing spine surgeries from 2012 to 2018 in a 3-hospital US metropolitan health network.¹⁶ In a risk-adjusted analysis, patients with estimated incomes <$31,000 and those residing in neighborhoods with higher diabetes prevalence and limited access to primary care providers were at increased risk for 30-day readmission. Further, each decile increase in the Area Deprivation Index of a patient's census tract was associated with 40% increased odds of readmission.¹⁶ The Yap et al systematic review of 30,987 adult spine surgery patients from 12 countries provided further evidence of the relationship between SDoH and outcomes.¹⁷ Seventy percent of analyses identified significant independent relationships between lower education and poorer outcomes, while 67% revealed an independent relationship between lower socioeconomic status and poorer outcomes, leading to the conclusion that these factors are clear independent contributors to poorer outcomes.¹⁷ A notable strength of the Yap et al study is its focus on functional outcomes, primarily pain and disability as measured by the Oswestry Disability Index, a validated patient-reported outcome measure.^18,19 However, the clinical and methodological heterogeneity of the studies included in the systematic review precluded the authors’ ability to perform a quantitative meta-analysis.

While these results demonstrate the importance of specific SDoH, others have found that aggregated SDoH risk may hold greater prognostic value than the presence of individual risk factors. Using a national US spine registry, Rethorn et al demonstrated that clusters of SDoH outperformed individual SDoH in predicting clinically meaningful improvements in disability, back pain, leg pain, quality of life, and patient satisfaction at 3 and 12 months following lumbar spine surgery.⁴ The study found that younger, minority, lower socioeconomic status patients were least likely to achieve clinically meaningful improvement in each of these outcome measures. These findings highlight the interconnected nature of SDoH and demographics and provide a methodological framework that may inform future approaches to SDoH research.

Collectively, the results of the studies described largely align with those of our current study. However, a strength of our study is its use of more granular SDoH data, expanding upon the commonly reported importance of socioeconomic status, race, and education. In addition to these factors, our results suggest in-home support and social connectivity may play a role in identifying patients at risk for suboptimal outcomes.

Racial disparity is considered an SDoH. In our study, we did not observe racial disparities; however, previous studies have illustrated differences in outcomes among White and non-White orthopedic patients. Stone et al examined the outcomes of 7,208 patients undergoing either total knee arthroplasty or total hip arthroplasty and found that African American patients had poorer outcomes for LOS and discharge disposition compared to White patients.²⁰ Sanford et al analyzed 4,803 spine surgery patients in the American College of Surgeons National Surgical Quality Improvement Program database and demonstrated that African American patients had a longer hospitalization by a full day and higher rates of postoperative complications, including deep vein thrombosis, pulmonary embolism, and surgical site infections, in comparison to White patients.¹⁰ Clearly, additional research across wide patient populations is needed to better understand the impact of racial disparities following various orthopedic surgeries.

Physicians and care teams need to assess patient health through a wide lens to optimize outcomes following surgery. Preoperative optimization may include both medical and social risk reduction, such as making healthy lifestyle choices before and after surgery and building a strong support system for postoperative care. An investment in nurse navigators could be a potential asset for connecting patients to public programs that can best serve them. Managing the complexities of SDoH, however, will require a team effort including housing authorities, food banks, and even schools, in addition to medical providers.²¹ Community programs that provide lifestyle and financial counseling have a potential benefit for patients and health care institutions alike, as the economic value of reducing SDoH disparities is as much as $1 trillion.^21-23 On a national level, the Healthy People 2030 initiative addresses SDoH in one of its 5 overarching goals: “Create social, physical, and economic environments that promote attaining the full potential for health and well-being for all.”⁷ This initiative collects data and recommends interventions that can be implemented on a community level to combat disparities within SDoH. The implementation of these strategies must be combined with long-term efforts to grow community strength, change social and cultural norms, and reduce the cost of healthy behaviors to create long-term sustainability.²³ While Healthy People 2030 addresses SDoH at the systemic level, our findings may help target interventions for the lumbar spine surgery population specifically.

This study was limited by its retrospective design at a single institution and thus may not be representative of the larger population. Furthermore, the inclusion criteria only required patients to have responded to a single question on the SR-SDoH questionnaire, resulting in incomplete data from some patients. Additionally, our inclusion of patients responding to the survey within 2 years of surgery introduced the risk that SDoH status changed during the study period or that surgery influenced patient behaviors. Further, the SR-SDoH instrument used in this study is not a validated measure. To enhance the reproducibility of this study and future SDoH studies, increased utilization of standardized instruments is required. To date, the lack of consensus definitions and standards for capturing SDoH data remains a challenge that has limited the rigor and reproducibility of studies related to the topic.^24,25

Despite these limitations, these results present a quantitative view of complex SDoH data in a spine patient population. Future efforts will likely include standard definitions, measures, and methods to capture data given the broad scope of SDoH, as well as its subjective definitions. Although we examined 10 distinct SDoH, other variables may have an impact on postoperative outcomes and should be investigated. Specific aspects of SDoH that were not evaluated in this study include health literacy, neighborhood crime and violence, and regional differences in access to health services.²⁶ Further, while multiple studies have evaluated the impact of overall comorbidity burden, specific comorbidities, opioid use, and patient-reported function on postoperative outcomes, the interaction between these factors and SDoH has not been explored.^27-32 Given the interconnected nature of traditional risk factors and SDoH, combining these variables to develop phenotypes of patients at risk for suboptimal outcomes after spine surgery is an opportunity for future research that would be highly applicable in practice. Finally, future studies should evaluate the relationship between SDoH and physical function and mental health status following spine surgery.