Fibromyalgia diagnosis and biased assessment: Sex, prevalence and bias

PurposeMultiple clinical and epidemiological studies have provided estimates of fibromyalgia prevalence and sex ratio, but different criteria sets and methodology, as well as bias, have led to widely varying (0.4%->11%) estimates of prevalence and female predominance (>90% to MethodsWe used a rheumatic disease databank and 2016 fibromyalgia criteria to study prevalence and sex ratios in a selection biased sample of 1761 referred and diagnosed fibromyalgia patients and in an unbiased sample of 4342 patients with no diagnosis with respect to fibromyalgia. We compared diagnostic and clinical variables according to gender, and we reanalyzed a German population study (GPS) (n = 2435) using revised 2016 criteria for fibromyalgia.ResultsIn the selection-biased sample of referred patients with fibromyalgia, more than 90% were women. However, when an unselected sample of rheumatoid arthritis (RA) patients was studied for the presence of fibromyalgia, women represented 58.7% of fibromyalgia cases. Women had slightly more symptoms than men, including generalized pain (36.8% vs. 32.4%), count of 37 symptoms (4.7 vs. 3.7) and mean polysymptomatic distress scores (10.2 vs. 8.2). We also found a linear relation between the probability of being females and fibromyalgia and fibromyalgia severity. Women in the GPS represented 59.2% of cases.DiscussionThe perception of fibromyalgia as almost exclusively (≥90%) a women’s disorder is not supported by data in unbiased studies. Using validated self-report criteria and unbiased selection, the female proportion of fibromyalgia cases was ≤60% in the unbiased studies, and the observed CritFM prevalence of fibromyalgia in the GPS was ~2%. ClinFM is the public face of fibromyalgia, but is severely affected by selection and confirmation bias in the clinic and publications, underestimating men with fibromyalgia and overestimating women. We recommend the use of 2016 fibromyalgia criteria for clinical diagnosis and epidemiology because of its updated scoring and generalized pain requirement. Fibromyalgia and generalized pain positivity, widespread pain (WPI), symptom severity scale (SSS) and polysymptomatic distress (PSD) scale should always be reported.研究目的：多项临床与流行病学研究已对纤维肌痛（fibromyalgia）的患病率及性别比进行了估算，但不同的诊断标准体系、研究方法以及偏倚因素，导致患病率与女性优势占比的估计值差异巨大（0.4%~11%），女性优势占比范围为>90%至[原文此处内容缺失]。 研究方法：本研究利用风湿病数据库与2016版纤维肌痛诊断标准，分别对选择性偏倚样本（1761例转诊并确诊的纤维肌痛患者）以及无偏倚样本（4342例未被诊断为纤维肌痛的患者）的患病率与性别比开展分析。我们按性别对比了诊断与临床变量，并采用修订后的2016版纤维肌痛诊断标准，重新分析了德国人群研究（GPS，n=2435）的队列数据。 研究结果：在选择性偏倚的转诊纤维肌痛患者样本中，超90%的患者为女性。但当对未经过筛选的类风湿关节炎（RA）患者开展纤维肌痛患病情况筛查时，纤维肌痛病例中女性占比仅为58.7%。女性患者的症状负荷略高于男性，具体表现为：广泛性疼痛发生率（36.8% vs 32.4%）、37项症状计数评分（4.7 vs 3.7）以及平均多症状困扰评分（10.2 vs 8.2）均更高。本研究还发现，女性性别与纤维肌痛患病风险及纤维肌痛严重程度之间存在线性关联。在德国人群研究中，纤维肌痛病例的女性占比为59.2%。 讨论：目前学界普遍认为纤维肌痛几乎完全（≥90%）为女性疾病，但这一认知并未得到无偏倚研究数据的支持。采用经过验证的自报告诊断标准并开展无偏倚入组后，无偏倚研究中的纤维肌痛病例女性占比≤60%；在德国人群研究中，观测到的CritFM纤维肌痛患病率约为2%。临床型纤维肌痛（ClinFM）是大众认知中的纤维肌痛代表，但临床与发表研究中的选择偏倚与确认偏倚会严重影响其结果，导致低估男性纤维肌痛患者数量、高估女性患者占比。鉴于2016版纤维肌痛诊断标准更新了评分体系并纳入了广泛性疼痛判定要求，我们推荐将其用于临床诊断与流行病学研究。需始终报告纤维肌痛及广泛性疼痛阳性情况、广泛性疼痛指数（Widespread Pain Index, WPI）、症状严重度量表（Symptom Severity Scale, SSS）以及多症状困扰量表（Polysymptomatic Distress Scale, PSD）。