Improvements in BMI are Observed After Spine Surgery at One, Two, and Three-Years Post-Operatively

Introduction: Spine surgery can provide improvements in chronic pain and mobility, leading to potential lifestyle modifications and improvements in long-term BMI, however this relationship remains largely unexplored.

Methods: A retrospective chart review was conducted for patients who underwent spine surgery at our institution between October 2016 to May 2020. Demographic information, pain scores, Patient Reported Outcomes Measurement Information System (PROMIS) scores, and BMI were collected on patients preoperatively and postoperatively at one, two, and three-year follow-up periods. Descriptive and regression analysis was conducted to examine the interplay between BMI, preclinical characteristics and outcomes at follow-up.

Results: 308 patients undergoing elective spine surgery at our institution were included in the study with 128 males and an average age of 66.5±11.7 years. Patients had a significant decrease in their BMIs at one-year (Difference= -0.712, 95% CI: -1.046,-0.378, p< 0.001), two-years (Difference= -0.598, 95% CI: -0.901, -0.296, p< 0.001), and three-years (Difference=-0.501, 95% CI: -0.779,-0.223, p< 0.001) postoperatively. Older age was a predictor of increased BMI changes by 3-years postoperatively (OR: 1.06, 95% CI 1.01,1.11, p< 0.05). Base pain scores and base PROMIS scores were not significant predictors of BMI change at any time point during three-year follow-up (p>0.05). Patients with a history of hypertension (OR=0.878, 95% CI: 0.781,0.987, p< 0.05) or an active smoker (OR=0.800, 95% CI: 0.649,0984 p< 0.05) were less likely to have significant BMI changes at one-year postoperatively, but this was not observed at two and three-year follow-up compared to patients without these conditions.

Conclusion : Spine surgery may influence improvements in BMI observed and maintained at one-year, two-year, and three-year timepoints postoperatively. However, patient comorbidities present preoperatively such as hypertension and tobacco smoking appear to negatively mediate this effect in short term, but not long-term timelines.