Body Mass Index Cutoffs Increase Health Care Racial Disparities in Patients with Cervical Myelopathy

Introduction: Body mass index (BMI) is often used by surgeons to decide whether to recommend surgery for patients with cervical myelopathy. However, BMI has historically had racially discriminative effects in the accessibility of some health care services. The purpose of this study is to investigate the implications of using a BMI cutoff to determine surgical eligibility in patients of different races with cervical myelopathy.

Methods: A retrospective review was performed at a single tertiary care hospital. Electronic medical records were queried for adult patients undergoing decompression surgery for cervical myelopathy between 2016 and 2020. Cohort characteristics were collected from medical records. Wilcoxon rank sum, student’s t-test, ANOVA, and chi-squared tests were used to evaluate outcomes between patients with BMI < 40 kg/m2 and BMI>=40 kg/m2 and between White and non-White patients. Statistical analysis was performed in MATLAB.

Results: 491 patients were included in the study. The average BMI was 29.09 kg/m2 with a standard deviation of 6.78 kg/m2. 458 patients had a BMI < 40 kg/m2, and 33 patients had a BMI >=40. Several other criteria used for surgical risk stratification including duration of symptoms, Charlson Comorbidity Index, and functional status did not differ between the cohorts comparing BMI or race. Post-operative outcomes including length of hospital stay, number of complications, and mortality also did not differ significantly between cohorts comparing BMI or race. However, when a BMI cutoff of 40 was implemented, race was significantly different between the groups. Patients with BMI >=40 kg/m2 were more likely to be non-White compared to patients with BMI < 40 kg/m2 (54.5% vs 34.5%, p=0.02).

Conclusion : Despite similar pre-operative eligibility metrics and post-operative outcomes between patients of varying BMI and race, a BMI cutoff of 40 significantly excluded patients who were non-White. Physicians utilizing a BMI cutoff as a sole risk stratification tool in patients with cervical myelopathy may be inadvertently increasing racial disparities. Spine surgeons should consider additional diagnostic measures of obesity when recommending treatment for cervical myelopathy.