Risk of Suicide Completion in Psychiatric Patients According to the Level of Continuity of Care and Area Deprivation: A Population-Based Nested Case-Control Study

Abstract

Background: Continuity of care (COC) and area deprivation (AD) have been implicated as possible risk factors of suicide in psychiatric patients. This nested case-control study aimed to examine the association between COC and AD and suicide completion in patients with psychiatric disorders. Methods: Data were collected from the Korean National Health Insurance Service National Sample Cohort, 2003-2013. The subjects were 974 patients with psychiatric disorders who completed suicides. Each case was compared to three control cases with propensity score matching by gender, age, and follow-up period with incidence density sampling, comprising the final control group of 2,922 living patients. Hazard ratios (HR) for suicide risk considering COC and area deprivation were analysed using a multiple conditional logistic regression. Outcomes: The average follow-up periods between the case and control groups were not statistically different (case: 277.6 weeks, control: 271.4 weeks, p = .245). Both poor COC and higher AD proved to be associated with increased risk of suicide (poor COC; adjusted HR [AHR]: 1.90, 95% confidence intervals [CI]: 1.45-2.49, highest AD; AHR: 1.80, 95% CI: 1.16-2.79). Lower COC combined with highest AD showed a negative synergistic effect on a highly increased risk of suicide (AHR: 3.18, 95% CI: 1.64-6.15). Age was effect modified between suicide risk and poor COC as well as suicide risk and higher AD. Interpretation: A strong patient-provider relationship with good COC may lead to a lower possibility of suicide in psychiatric patients. Moreover, improving community capacity for suicide prevention as well as appropriate postvention should be addressed. Funding: None. Declaration of Interest: None of the authors have any financial interests or potential conflicts of interest to declare. Ethical Approval: All personal information in this data were de-identified by the KNHIS before distribution; therefore, the institutional review board of Yonsei University confirmed that this study is eligible for exemption from full institutional review board review.