精神科醫師密度與自殺率關聯性：臺灣全國性樣本的多層次個案對照研究

Abstract

研究背景：自殺是重要的公共衛生議題，精神醫療資源可近性可能為影響該地區自殺率的重要因子，然而過去精神醫療資源可近性與自殺之關聯性研究呈現不一致的結果，此不一致性可能自於不同研究間對於個人/地區層次特性的校正程度差異。 研究目的：本研究旨在校正已知影響自殺之重要個人及地區層次特性的情況下，探討精神科醫師密度及自殺率之關聯性。 研究方法：本研究自全國死因資料庫中納入2007年至2017年的所有自殺個案，每個自殺案例皆自健保承保檔中以年齡－性別匹配十名對照個案，並將所有個案依戶籍地分配至臺灣355個鄉鎮之一。本研究使用多層次模型估計自殺的勝算比（OR）與個人/地區層次變項的關聯性。精神科醫師密度之定義為每10萬人口之精神科醫師人數，取四分位數作為類別變項[Q1（0.01-3.02）；Q2（3.02-7.20）；Q3（7.20-13.82）；和Q4（>13.82）]，比較無精神科醫師鄉鎮與有精神科醫師鄉鎮的自殺勝算比。 結果： 本研究共納入40,930例自殺個案和409,300名年齡－性別匹配的對照個案。經校正個人層次變項（就業狀況、月收入、身體共病症和精神障礙診斷）及地區社經特性後，精神科醫師密度與自殺呈現負相關，精神科醫師密度Q1至Q4之校正後自殺勝算比及95%信賴區間分別為0.95, (0.90-1.01)，0.90, (0.85-0.96)，0.89, (0.83-0.94)，以及0.89, (0.83-0.95)。 結論：精神醫療資源可近性為自殺之潛在保護因子，提升地區精神醫療資源可近性或可做為自殺防治策略之一環。

Background: Access to psychiatric services could be an important factor influencing local suicide rates, but previous studies showed inconsistent findings in the association between psychiatrist density and suicide. The inconsistency could result from different levels of controlling of individual- and area-level characteristics. Aim: To investigate the association between psychiatrist density and suicide, accounting for individual- and area-level characteristics. Methods: We investigated all suicide cases in 2007-2017 identified from the national cause-of-death data files, with each suicide case matched to ten controls by age and sex and each suicide case/control assigned to one of the 355 townships across Taiwan. Our primary outcomes were the odds ratios (OR) of suicide and its 95% confidence interval (CI) estimated via multi-level models, which included both individual-level and area-level characteristics. Townships with no psychiatrists were compared with the quartiles of townships with psychiatrists (density per 100,000 population): Q1 (0.01-3.02); Q2 (3.02-7.20); Q3 (7.20-13.82); and Q4 (>13.82). Results: A total of 40,930 suicide cases and 409,300 age-sex-matched controls were included. We found that increased psychiatrist density was associated with decreased suicide risk (Q1: adjusted OR [aOR]=0.95 [95% CI 0.90-1.01]; Q2: aOR=0.90 [95% CI 0.85-0.96]; Q3: aOR=0.89 [95% CI 0.83-0.94]; Q4: aOR=0.89 [95% CI 0.83-0.95]) after adjusting for individual-level characteristics (employment state, monthly income, physical comorbidities, and the diagnosis of psychiatric disorders) and area socioeconomic characteristics. Conclusions: The psychiatrist density-suicide association suggests an effect of increased availability of psychiatric services on preventing suicide. Suicide prevention strategies could usefully focus on enhancing local access to psychiatric services.