Smartphone accelerometers as tools to study the effect of socioeconomic disparities in neurosurgical outcomes: a multi-institutional retrospective analysis.

Objective: Smartphones and wearable devices can be effective tools to objectively assess patient mobility and well-being before and after spine surgery. In this retrospective observational study, the authors investigated the relationship between these longitudinal perioperative patient activity data and socioeconomic and demographic correlates, assessing whether smartphone-captured metrics may allow neurosurgeons to distinguish intergroup patterns.

Methods: A multi-institutional retrospective study of patients who underwent spinal decompression with and without fusion between 2017 and 2021 was conducted. Patients' home zip codes were used to determine each patient's Area Deprivation Index (ADI)-an independently validated composite measure of the socioeconomic health of a specific neighborhood relative to the entire United States. Activity data, including steps-taken-per-day across a 2-year perioperative period, were extracted from patient smartphones and statistically normalized to enable interpatient comparisons. Multivariate regression was performed to identify relationships between ADI and patient mobility, while controlling for confounders including age and obesity.

Results: The study included 49 patients. The preoperative activity level of patients living in neighborhoods with an ADI score below the 80th percentile nationally was significantly greater than that of patients living in neighborhoods above the 80th percentile (p = 0.011). A direct positive correlation existed between patients' ADI scores and the number of days with below-average steps-taken-per-day during the preoperative period (adjusted r2 = 0.822, p = 0.049). Postoperatively, patients with ADI scores above the 80th percentile had significantly greater documented activity levels (p = 0.031).

Conclusions: The authors' study demonstrates that individuals living in neighborhoods with an ADI score below the 80th percentile had higher preoperative activity than patients in neighborhoods above the 80th percentile; this disparity diminishes after spine surgery. Though these findings are not generalizable, the authors hypothesized that the relatively faster postoperative recovery of patients living in wealthier neighborhoods is likely multifactorial, possibly due to sustained activity in the preoperative and likely symptomatic period of patients in lower-income neighborhoods, as well as enhanced access to postoperative care for patients in higher-income neighborhoods. Overall, the findings from the authors' study demonstrate that smartphone-captured activity may be utilized as a metric to study socioeconomic disparities in surgical outcomes. Future studies must specifically isolate socioeconomic variables as potential causal factors to inform improvements in healthcare delivery after surgery.