目的：利用健保資料庫比較類風濕性關節炎與骨關節炎患者後續罹患憂鬱症之風險差異。方法：使用2000～2013年全民健保承保歸人檔資料（LHID2005），以類風濕性關節炎患者為實驗組，將人口學特性及健康情形等變項，利用傾向分數1:3配對法篩選出骨關節炎患者為對照組。研究對象皆自確診關節炎疾病後追蹤有無發生憂鬱症至2013年底，再以Cox比例風險模式估算憂鬱症之罹病風險。結果：類風濕性關節炎病人比骨關節患者有高於3.33倍的憂鬱症罹病風險，95%信賴區間為2.21到5.01，達統計顯著水準；相較於男性，女性的罹病風險約為男性的1.75倍，95%信賴區間為0.98到3.13。結論：類風濕性關節炎患者有較高機會罹患憂鬱症，此結果可供臨床醫師評估患者的心理變化並適當地給予心理支持。

Objectives: The objective of this study was to compare the risk of depression onset between rheumatoid arthritis (RA) and osteoarthritis (OA) patients by using the National Health Insurance Research Database of Taiwan. Methods: We selected cases of RA and OA from the NHI beneficiaries claims data from 2000 to 2013. Patients diagnosed with RA during the examined period were identified according to the ICD-9-CM classification, and patients with OA were selected using propensity score matching. The members of the matched cohort were followed up till December 31, 2013, to check for the first onset of depression, and those without depression were censored. Cox proportional hazards regression was used to estimate the risk of depression onset. Results: The hazard ratio (HR) for depression onset was 3.33 times higher in the RA cohort than in the control cohort (95% confidence interval [CI] = 2.21-5.01). Moreover, the risk of depression was higher for females (HR = 1.75, 95% CI = 0.98-3.13) than for males. Conclusions: Patients with RA have a significantly higher risk of depression than patients with OA. Therefore, the mental health status of RA patients should be considered when deciding on appropriate care.