Influence of affective disorders on outcomes after suboccipital decompression for adult Chiari I malformation

Introduction: Affective disorders (AD) have been shown to influence patient outcomes and healthcare resource utilization across several pathologies, though this relationship has not been described in patients with Chiari I malformations (CM-I). The aim of this study was to determine the impact of comorbid AD on postoperative events and healthcare resource utilization in adults following suboccipital decompression for CM-I. Methods: A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults who underwent suboccipital decompression for CM-I were identified using ICD-10-CM codes. Patients were stratified into two cohorts, those with AD and those without (No AD). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of prolonged length of stay (LOS), exorbitant admission costs, and non-routine discharge (NRD). Results: A total of 3985 patients were identified, of which 2780 (69.8%) were in the No AD cohort and 1205 (30.2%) were in the AD cohort. Patient demographics were similar, except for a greater proportion of Female patients than the No AD cohort (p = 0.004). Prevalence of some comorbidities varied between cohorts, including obesity (p = 0.030), ADHD (p < 0.001), GERD (p < 0.001), smoking (p < 0.001), and chronic pulmonary disease (p < 0.001). The AD cohort had a greater proportion of patients with 1-2 (p < 0.001) or >= 3 comorbidities (p < 0.001) compared to the No AD cohort. A greater proportion of patients in the AD cohort presented with headache compared to the No AD cohort (p = 0.003). Incidence of syringomyelia was greater in the No AD cohort (p = 0.002). A greater proportion of patients in the No AD cohort underwent duraplasty only (without cervical laminectomy) compared to the AD cohort (p = 0.021). Healthcare resource utilization was similar between cohorts, with no significant differences in mean LOS (No AD: 3.78 +/- 3.51 days vs. 3.68 +/- 2.71 days, p = 0.659), NRD (No AD: 3.8% vs. AD: 5.4%, p = 0.260), or mean admission costs (No AD: $20,254 +/- 14,023 vs. AD: $29,897 +/- 22,586, p = 0.284). On multivariate analysis, AD was not independently associated with extended LOS [OR (95%CI): 1.09 (0.72-1.65), p = 0.669], increased hospital costs [OR (95%CI): 0.98 (0.63-1.52), p = 0.930], or NRD [OR (95%CI): 1.39 (0.65-2.96), p = 0.302]. Conclusion: Our study suggests that the presence of an AD may not have as much of an impact on postoperative events and healthcare resource utilization in adult patients undergoing Chiari decompression. Additional studies may be warranted to identify other potential implications that AD may have in other aspects of healthcare in this patient population.