BACKGROUND AND OBJECTIVES Epidemiologic studies suggest increasing incidence and prevalence of myasthenia gravis (MG) among the elderly population outside the United States. We aimed to provide an estimation of MG incidence and prevalence and their trend among the Medicare Fee-For-Service (FFS)-covered elderly US population. METHODS We performed a retrospective longitudinal study using Medicare claims data (2006-2019). Study-eligible beneficiaries were aged 65 years and older, had at least 1 month of FFS Part A/B coverage, and were without any health maintenance organization insurance coverage. Study-eligible beneficiaries were aggregated into 2-year periods from 2006-2007 through 2018-2019. MG cases were ascertained using a validated algorithm of 2 MG claims within each 2-year period, from 2 outpatient office visits or a combination of 1 inpatient admission and 1 outpatient office visit, separated by ≥ 28 days. Period prevalence was calculated from MG-ascertained cases divided by FFS Part A/B beneficiaries and reported as cases per 100,000 population. Incident cases were determined among MG prevalent cases if the initial MG claim occurred in that period after a full calendar year since coverage initiation. Incidence was calculated as case counts per 100,000 at-risk beneficiary person-years (PYs) in each period excluding 2006-2007. Trends of prevalence and incidence over time were examined with Poisson regression. All-cause mortality of each 2-year period was calculated. RESULTS The period prevalence of MG increased from 81 to 119 per 100,000 FFS A/B population from 2006-2007 to 2018-2019 (p < 0.001). Increasing trends of prevalence were observed in all sex (male/female), age (65-69/70-74/75-79/80+), race/ethnic (African American/Asian/Hispanics of any race/non-Hispanic White/other), and census region (Northeast/Midwest/South/West) subgroups. MG incidence increased from 12.2 to 13.3 per 100,000 PYs from 2008-2009 to 2018-2019 (p < 0.05). Increasing incidence trends were significant in the following subgroups: men and women; all age groups except 75-79 years; White non-Hispanic race; Northeast, Midwest, and South census regions. All-cause mortality among MG beneficiaries was stable from 6.26 deaths per 100 PYs in 2006-2007 to 5.67 in 2018-2019 (p = 0.18). DISCUSSION Increasing trends in MG prevalence and incidence in the elderly US population, with variation in rates of certain subgroups, are confirmed in this 14-year period.

中文翻译：

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美国老年人群重症肌无力的流行病学研究：医疗保险索赔数据库的纵向分析，2006-2019 年。


背景和目标 流行病学研究表明，在美国以外的老年人群中，重症肌无力 （MG） 的发病率和患病率不断增加。我们旨在估计 MG 的发病率和患病率及其在 Medicare 按服务收费 （FFS） 覆盖的美国老年人群中的趋势。方法 我们使用 Medicare 索赔数据 （2006-2019） 进行了一项回顾性纵向研究。符合研究条件的受益人年龄在 65 岁及以上，至少有 1 个月的 FFS A/B 部分保险，并且没有任何健康维护组织保险。符合研究条件的受益人被汇总为 2006-2007 年至 2018-2019 年的 2 年期间。MG 病例是使用经过验证的算法确定的，即每 2 年期间 2 次 MG 索赔，从 2 次门诊就诊或 1 次住院和 1 次门诊就诊的组合，间隔 ≥ 28 天。经期患病率是用 MG 确定的病例除以 FFS A/B 部分受益人计算的，并以每 100,000 人中的病例数报告。如果最初的 MG 索赔发生在保险开始后一整年之后的那个时期，则在 MG 流行病例中确定事件案例。发病率计算为除 2006-2007 年以外的每个时期每 100,000 名高危受益人年 （PY） 的病例数。用泊松回归检查患病率和发病率随时间变化的趋势。计算每 2 年期间的全因死亡率。结果 从 2006-2007 年到 2018-2019 年，MG 的患病率从每 100,000 个 FFS A/B 人群 81 个增加到 119 个 （p < 0.001）。 在所有性别（男性/女性）、年龄（65-69/70-74/75-79/80+）、种族/民族（任何种族的非裔美国人/亚洲/西班牙裔/非西班牙裔白人/其他）和人口普查地区（东北/中西部/南部/西部）亚组中观察到患病率增加趋势。从 2008-2009 年到 2018-2019 年，MG 发病率从每 100,000 PY 12.2 例增加到 13.3 例 （p < 0.05）。以下亚组的发病率增加趋势显著： 男性和女性;除 75-79 岁外的所有年龄组;非西班牙裔白人种族;东北部、中西部和南部人口普查区域。MG 受益人的全因死亡率从 2006-2007 年的每 100 PY 6.26 例死亡稳定到 2018-2019 年的 5.67 例 （p = 0.18）。讨论在这 14 年期间，美国老年人群 MG 患病率和发病率呈上升趋势，某些亚组的发病率存在差异。