Hidradenitis suppurativa (HS) has been associated with a high prevalence of spondyloarthritis; however, the population-based risk of developing inflammatory arthritis remains unclear.¹ This population-based cohort study sought to evaluate the risk of developing inflammatory arthritis among patients with HS compared with matched patients without HS.

We used longitudinal claims data from commercially insured patients, including those with Medicaid and Medicare, covering 185 million lives in the United States between January 1, 2003, and January 1, 2016. We identified patients of all ages who received a diagnosis of HS (International Classification of Diseases, Ninth Revision code 705.83 or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision code L73.2), defined as 1 diagnosis by a dermatologist or 3 diagnoses by any health care professional.² The cohort entry date for the HS group was the first recorded diagnosis date of HS after at least 180 days of continuous enrollment (eFigure in the Supplement). For the non-HS group, we risk-set sampled 2 patients without HS from all plan enrollees who did not have a diagnosis of HS matched on the date the patient with HS entered the cohort. We excluded patients who had less than 180 days of continuous enrollment before cohort entry or had preexisting inflammatory arthritis, including ankylosing spondylitis, psoriatic arthritis, other spondyloarthritis, or rheumatoid arthritis (eAppendix in the Supplement). The Brigham and Women’s Hospital’s Institutional Review Board approved this study. All patient information was deidentified.

化脓性汗腺炎（HS）与脊椎关节炎的高患病率有关。然而，基于人群的发炎性关节炎风险仍然不清楚。¹这项基于人群的队列研究旨在评估HS患者与相匹配的HS患者之间发生炎性关节炎的风险。

我们使用了来自商业保险患者的纵向索赔数据，其中包括那些拥有Medicaid和Medicare的患者，其在2003年1月1日至2016年1月1日期间覆盖了美国1.85亿人的生命。我们确定了所有年龄段接受过HS诊断的患者（国际疾病分类，第九修订版代码705.83或国际疾病和相关健康问题的统计分类，第十修订版代码L73.2），定义为由皮肤科医生进行1次诊断或由任何卫生保健专业人员进行3次诊断。²HS组的队列输入日期是连续入组至少180天后首次记录的HS诊断日期（补编中的数字）。对于非HS组，我们对所有计划参与者中有2例没有HS的患者进行风险分析，这些患者在HS进入患者队列之日未诊断出HS匹配。我们排除了入组前连续入学少于180天或已存在炎性关节炎（包括强直性脊柱炎，银屑病关节炎，其他脊椎关节炎或类风湿性关节炎）的患者（补遗中的e附录）。布莱根妇女医院的机构审查委员会批准了这项研究。所有患者信息均已被识别。