Hypercalcemia in monoclonal gammopathy of undetermined significance (MGUS) presents a clinical challenge since it may indicate progression to multiple myeloma (MM) but could also be due to a multitude of unrelated disorders. To inform the approach to this clinical challenge, we conducted a nested cohort study within the iStopMM screening study. Of the 75,422 Icelanders aged 40 years and above who underwent screening for MGUS, we included 2,546 with MGUS who were in active follow-up, including regular serum calcium measurements. In total, 191 individuals (7.5%) had hypercalcemia detected at least once, of whom 93 had persistent hypercalcemia (48.7%). MM was found in 3 participants with persistent hypercalcemia (3.2%); all had concurrent bone disease and other end-organ damage. The most common causes of hypercalcemia were primary hyperparathyroidism (56.0%) and malignancies other than MM (16.0%). In this first comprehensive study on hypercalcemia in MGUS, we observed that hypercalcemia rarely indicated MGUS progression and never in the absence of other symptoms of MM. More than half of hypercalcemia cases were transient and the underlying causes were similar to those in the general population. We conclude that hypercalcemia in MGUS should be approached in the same way as in those without MGUS.

中文翻译：

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处理意义未明的单克隆丙种球蛋白病中的高钙血症：来自 iStopMM 研究的见解。


意义未明的单克隆丙种球蛋白病 （MGUS） 中的高钙血症带来了临床挑战，因为它可能表明进展为多发性骨髓瘤 （MM），但也可能是由于多种不相关的疾病。为了告知应对这一临床挑战的方法，我们在 iStopMM 筛查研究中进行了一项嵌套队列研究。在 75,422 名 40 岁及以上接受 MGUS 筛查的冰岛人中，我们纳入了 2,546 名正在积极随访（包括定期血清钙测量）的 MGUS 患者。总共有 191 人 （7.5%） 至少检测到一次高钙血症，其中 93 人患有持续性高钙血症 （48.7%）。在 3 例持续性高钙血症参与者中发现 MM （3.2%）;所有患者均并发骨病和其他终末器官损伤。高钙血症最常见的原因是原发性甲状旁腺功能亢进症 （56.0%） 和 MM 以外的恶性肿瘤 （16.0%）。在这项关于 MGUS 高钙血症的首次全面研究中，我们观察到高钙血症很少表明 MGUS 进展，而且从未在没有 MM 的其他症状的情况下出现。超过一半的高钙血症病例是一过性的，其根本原因与一般人群相似。我们得出结论，MGUS 患者的高钙血症应采用与无 MGUS 患者相同的处理方式。