Characteristics of the study population by sex.

Background
Self-harm is a major public health concern globally and in South Africa. Individuals with a history of self-harm are at increased risk of unnatural death, including suicide and fatal accidents. This study investigates the incidence and predictors of self-harm and its role as a predictor for subsequent unnatural death.
Methods and findings
We conducted a cohort study using insurance claims and vital registration data from beneficiaries of South African medical insurance schemes (2011–2022), aged 10 years or older. We estimated the cause-specific cumulative incidences of healthcare encounters for intentional self-harm (International Classification of Diseases 10th Revision [ICD-10] codes X60-X84) and unnatural deaths (ICD-10 codes V01-Y98), using the Aalen–Johansen method. We assessed predictors of both outcomes using Cox regression. We followed 1,356,119 beneficiaries (median age 33 years, 52.2% female) for a median of 3 years, during which 7,510 (0.6%) had a healthcare encounter for self-harm. The 5-year cumulative incidence of self-harm ranged from 0.2% in males aged 10–14 to 2.1% in females aged 15–24. Sex, age, and mental disorders were strong predictors for self-harm, while HIV was a modest predictor. Among individuals who survived a self-harm event, the five-year cumulative incidence of subsequent unnatural death was 3.43% (95% CI [2.38, 4.76]) for males and 0.77% (95% CI [0.48, 1.19]) for females. Non-fatal self-harm was a strong predictor of subsequent unnatural death in both males (hazard ratio [HR] 7.03, 95% CI [5.27, 9.39]) and females (HR 4.63, 95% CI [3.00, 7.15]). The study’s main limitations include potential under-ascertainment of self-harm incidence due to reliance on routine data, and the unavailability of the exact cause of death, preventing analysis of suicide.
Conclusion
Self-harm is common among beneficiaries of South African private medical insurance, with the highest risk in young females and individuals with mental disorders. These groups may benefit from targeted screening and early intervention. Non-fatal self-harm was a strong predictor of subsequent unnatural death, underscoring the need for suicide-specific brief interventions for individuals presenting with self-harm.

研究背景
自我伤害（Self-harm）是全球及南非范围内的重大公共卫生问题。有自我伤害史的个体发生非自然死亡（包括自杀与致命事故）的风险显著升高。本研究旨在探讨自我伤害的发生率及其影响因素，并明确其作为后续非自然死亡预测因子的作用。

研究方法与结果
本研究依托2011年至2022年南非医疗保险计划受益人群的保险理赔数据与生命登记数据，开展了一项队列研究，研究对象为10岁及以上人群。我们采用阿伦-约翰森（Aalen–Johansen）法，估算了意向性自我伤害（国际疾病分类第10版（International Classification of Diseases 10th Revision，ICD-10）编码X60-X84）以及非自然死亡（ICD-10编码V01-Y98）的医疗就诊病因特异性累积发生率。我们通过Cox回归分析评估了两种结局的影响因素。本研究共纳入1,356,119名受益人群，中位年龄为33岁，女性占比52.2%，中位随访时长为3年。随访期间，共有7,510名（0.6%）个体因自我伤害接受医疗就诊。自我伤害的5年累积发生率在10-14岁男性群体中为0.2%，在15-24岁女性群体中则高达2.1%。性别、年龄与精神障碍是自我伤害的强预测因子，而HIV感染则为轻度预测因子。在曾发生自我伤害但幸存的个体中，男性后续5年非自然死亡的累积发生率为3.43%（95%置信区间[2.38, 4.76]），女性为0.77%（95%置信区间[0.48, 1.19]）。无论男性（风险比[HR] 7.03, 95% CI [5.27, 9.39]）还是女性（HR 4.63, 95% CI [3.00, 7.15]），非致命性自我伤害均为后续非自然死亡的强预测因子。本研究存在若干主要局限性：其一，依赖常规数据可能导致自我伤害发生率漏报；其二，无法获取确切死因，无法开展自杀相关的细分分析。

研究结论
南非私人医疗保险受益人群中自我伤害较为常见，年轻女性及精神障碍个体的自我伤害风险最高。此类人群可从针对性筛查与早期干预中获益。非致命性自我伤害是后续非自然死亡的强预测因子，这凸显了为因自我伤害就诊的个体开展自杀相关简短干预的必要性。