Supplementary Material for: Are Respiratory Abnormalities Specific for Panic Disorder? A Meta-Analysis

<b><i>Objectives:</i></b> There is evidence of baseline respiratory abnormalities in panic disorder (PD), but whether they are specific to PD remains unclear. To investigate this issue, we meta-analyzed results from studies comparing baseline respiratory and hematic variables between subjects with PD and subjects with other anxiety disorders. <b><i>Methods:</i></b> A literature search in bibliographic databases was performed. Fixed-effects models were applied. Several moderator analyses and publication bias diagnostics were performed. <b><i>Results:</i></b> We found: (1) significantly lower mean end-tidal partial pressure of CO₂ (et-pCO₂) in subjects with PD than in those with social phobia (SP) or generalized anxiety disorder (GAD), and (2) higher mean respiratory rate, lower venous et-pCO₂ and HCO₃^- concentration in subjects with PD than in those with SP. No publication bias was found. <b><i>Conclusions:</i></b> Subjects with PD show a condition of baseline hyperventilation when compared to subjects with SP or GAD. Hematic variables suggest that the hyperventilation may be chronic. These results support the idea that baseline respiratory abnormalities are specific to PD pathophysiology. Further studies are needed to clarify whether these abnormalities are related to a malfunction of the respiratory system or to specific cognitive/emotional/behavioral factors in this population.

<b><i>研究目的：</i></b> 已有证据表明惊恐障碍（Panic Disorder, PD）患者存在基线呼吸异常，但此类异常是否仅特异性出现于惊恐障碍仍尚不明确。为探究该问题，本研究对比较惊恐障碍患者与其他焦虑障碍患者的基线呼吸及血液学指标的相关研究结果进行了元分析。<b><i>研究方法：</i></b> 本研究在文献数据库中开展了文献检索，采用固定效应模型进行分析，并开展了多项调节效应分析与发表偏倚诊断。<b><i>研究结果：</i></b> 本研究发现：（1）相较于社交恐惧症（Social Phobia, SP）或广泛性焦虑障碍（Generalized Anxiety Disorder, GAD）患者，惊恐障碍患者的潮气末二氧化碳分压（end-tidal partial pressure of CO₂, et-pCO₂）均值显著更低；（2）相较于社交恐惧症患者，惊恐障碍患者的呼吸频率均值更高，静脉潮气末二氧化碳分压（et-pCO₂）与碳酸氢根离子（HCO₃⁻）浓度均值更低。本研究未发现显著发表偏倚。<b><i>研究结论：</i></b> 相较于社交恐惧症或广泛性焦虑障碍患者，惊恐障碍患者基线状态下存在过度换气状态。血液学指标提示该过度换气可能为慢性过程。上述结果支持“基线呼吸异常为惊恐障碍病理生理学特异性表现”这一观点。未来仍需开展进一步研究，以明确此类异常是与呼吸系统功能障碍相关，还是与该人群特有的认知、情绪或行为因素相关。