From the Department of Health and Medical Psychology, Institute of Psychology, Leiden University, the Netherlands.
Psychosom Med. 2021 Jan 1;83(1):2-15. doi: 10.1097/PSY.0000000000000874.
Medically unexplained physical symptoms (MUPS) and related syndromes are common and place a substantial burden on both patients and society. Chronic psychological distress and dysregulation of the autonomic nervous system may be common factors associated with MUPS, although previous studies have reported mixed results. The aims of this meta-analysis are to provide an updated synthesis of studies investigating heart rate variability (HRV) indices associated with autonomic nervous system functioning in three common MUPS syndromes and to explain inconsistencies in previous study findings.
Literature search yielded 58 studies comparing HRV indices of reduced parasympathetic activity of healthy individuals with those of patients with chronic fatigue syndrome (npatients = 271), irritable bowel syndrome (npatients = 1005), and fibromyalgia (npatients = 534). Separate random-effects meta-analyses were conducted on studies measuring root mean square of successive differences (RMSSD) and high-frequency HRV (HF-HRV).
Regardless of syndrome type, patients had significantly lower RMSSD (k = 22, Hedges g = -0.37 [-0.53 to -0.21], p < .001) and HF-HRV (k = 52, Hedges g = -0.69 [-1.03 to -0.36], p < .001) than did healthy individuals. Sample age and publication year explained a substantial variation in RMSSD, whereas controlling for confounders in statistical analyses explained variation in HF-HRV.
Lower RMSSD and HF-HRV in patients with MUPS versus healthy controls indicates that autonomic nervous system dysregulation, particularly lower parasympathetic activity, may play a role in patients with these conditions. This conclusion may have important implications for the underlying mechanisms and treatment of MUPS and related syndromes.
无法用医学解释的身体症状（MUPS）及相关综合征较为常见，给患者和社会都带来了沉重的负担。慢性心理压力和自主神经系统失调可能是与 MUPS 相关的常见因素，尽管之前的研究结果不一。本荟萃分析旨在综合分析三项常见 MUPS 综合征中与自主神经系统功能相关的心率变异性（HRV）指标的研究，以解释之前研究结果的差异。
文献检索共获得 58 项研究，比较了慢性疲劳综合征（npatients = 271）、肠易激综合征（npatients = 1005）和纤维肌痛综合征（npatients = 534）患者的 HRV 指标与健康个体的 HRV 指标。对测量均方根差（RMSSD）和高频 HRV（HF-HRV）的研究分别进行了随机效应荟萃分析。
无论综合征类型如何，患者的 RMSSD（k = 22，Hedges g = -0.37 [-0.53 至 -0.21]，p <.001）和 HF-HRV（k = 52，Hedges g = -0.69 [-1.03 至 -0.36]，p <.001）均显著低于健康个体。RMSSD 的变异可由样本年龄和发表年份解释，而在统计分析中控制混杂因素则可以解释 HF-HRV 的变异。
MUPS 患者与健康对照相比，RMSSD 和 HF-HRV 较低，表明自主神经系统失调，尤其是副交感神经活动降低，可能在这些情况下发挥作用。这一结论可能对 MUPS 及相关综合征的潜在机制和治疗具有重要意义。
