Supplementary Material for: Association of borderline personality disorder with physical diseases and mortality: a 16-year population-based electronic health-record cohort study in Hong Kong

Introduction: Borderline-personality-disorder (BPD) research is scarce. This study quantified risks of physical-diseases and assessed mortality patterns in individuals with BPD. Methods: This retrospective population-based cohort study investigated individuals with a first-recorded diagnosis of BPD in 2006–2021, utilizing a medical-record database of public-healthcare services in Hong-Kong. Individuals without mental-disorders attending primary-care-clinics in the study-period served as unexposed-comparison (i.e., PCC cohort). We estimated risks of physical-diseases and all-cause and cause-specific mortality using Cox-proportional hazards-regression models, and calculated excess life-years lost (LYLs). Results: This analysis included 3092 patients with BPD and 902927 individuals in the PCC cohort. BPD was associated with increased risks of a wide-spectrum of physical-diseases, with the highest hazards-ratio (HR) for epilepsy (7.58 [95% confidence-intervals:5.33–10.79]). HRs for other physical-diseases ranged from 1- to 3-fold higher than the PCC cohort. Individuals with BPD experienced elevated risk of all-cause (5.65 [4.83–6.61]), natural-cause (2.02 [1.56–2.62]) and external-cause mortality (30.35 [23.52–39.17]), with suicide and cardiovascular-diseases as the leading-contributors. External-causes accounted for 40.4% of deaths in BPD, while natural-causes explained 37.3%. The excess-LYL for BPD was 13.01 years (9.35–15.52). The association between BPD and physical-diseases generally became statistically non-significant among males but remained significantly elevated among females. BPD-associated all-cause mortality risk was higher in females than males. Statistically-significant associations between BPD and physical-diseases were predominantly-observed in individuals with BPD-diagnoses at younger-ages. Conclusion: BPD is associated with increased risk of physical-diseases, excess-mortality and reduced life-expectancy. Suicide-prevention strategies and physical-health monitoring are urgently-warranted to reduce physical-health disparities and premature-mortality in BPD.