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Background
Despite the increasing number of cases of secondary antibody deficiency (SAD) and immunoglobulin (Ig) utilization, there is a paucity of data in the literature on clinical and patient-reported outcomes in this population.
Objective
To describe immunoglobulin utilization patterns, clinical and patient-reported outcomes in patients with SAD on immunoglobulin replacement therapy (IgRT).
Methods
A cross-sectional study of patients with secondary antibody deficiency enrolled in the Ontario Immunoglobulin Treatment (ONIT) Case Registry from June 2020 to September 2022 was completed. Demographics, comorbidities, indications for immunoglobulin treatment, clinical infections at baseline and post IgRT, and patient-reported outcomes were collected and analyzed.
Results
There were 140 patients (58 males; 82 females; median age 68) with SAD during the study period; 131 were on subcutaneous Ig (SCIG) and 9 were on intravenous Ig (IVIG). The most common indication was chronic lymphocytic leukemia (CLL) (N = 52). IgRT reduced the average annual number of infections by 82.6%, emergency room (ER) visits by 84.6%, and hospitalizations by 83.3%. Overall, 84.6% of patients reported their health as better compared to before IgRT. Among those patients who switched from IVIG to SCIG (N = 35), 33.3% reported their health as the same, and 62.9% reported their health as better.
Conclusions
This study demonstrates that IgRT significantly improved clinical outcomes and patient-reported general health state in patients with SAD. This study also further supports the use of SCIG in patients with SAD.

背景：尽管继发性抗体缺乏症（secondary antibody deficiency, SAD）的病例数与免疫球蛋白（immunoglobulin, Ig）的使用量持续增长，但现有文献中针对该人群的临床结局及患者报告结局的相关数据仍较为匮乏。
研究目的：旨在描述接受免疫球蛋白替代治疗（immunoglobulin replacement therapy, IgRT）的继发性抗体缺乏症患者的免疫球蛋白使用模式、临床结局与患者报告结局。
研究方法：本研究针对2020年6月至2022年9月期间纳入安大略省免疫球蛋白治疗（Ontario Immunoglobulin Treatment, ONIT）病例登记库的继发性抗体缺乏症患者开展横断面研究。研究收集并分析了患者的人口学特征、合并症、免疫球蛋白治疗指征、基线及免疫球蛋白替代治疗后的临床感染情况，以及患者报告结局相关数据。
研究结果：研究期间共纳入140例继发性抗体缺乏症患者（男性58例，女性82例；中位年龄68岁），其中131例接受皮下注射免疫球蛋白（subcutaneous Ig, SCIG）治疗，9例接受静脉注射免疫球蛋白（intravenous Ig, IVIG）治疗。最常见的治疗指征为慢性淋巴细胞白血病（chronic lymphocytic leukemia, CLL）（N=52）。免疫球蛋白替代治疗可使患者年均感染次数降低82.6%，急诊室（emergency room, ER）就诊次数降低84.6%，住院次数降低83.3%。总体而言，84.6%的患者表示其健康状况较接受免疫球蛋白替代治疗前有所改善。在由静脉注射免疫球蛋白转换为皮下注射免疫球蛋白的患者中（N=35），33.3%的患者表示健康状况无明显变化，62.9%的患者表示健康状况有所改善。
研究结论：本研究证实，免疫球蛋白替代治疗可显著改善继发性抗体缺乏症患者的临床结局与患者报告的整体健康状态，同时进一步支持了皮下注射免疫球蛋白在继发性抗体缺乏症患者中的临床应用。