Wang Lindsey, Berger Nathan A, Kaelber David C, Davis Pamela B, Volkow Nora D, Xu Rong
Center for Artificial Intelligence in Drug Discovery, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
Center for Science, Health, and Society, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
medRxiv. 2022 Feb 22:2022.02.21.22271300. doi: 10.1101/2022.02.21.22271300.
SARS-CoV-2 infections and hospitalizations are rising in the US and other countries after the emergence of the Omicron variant. Currently, data on infection rates, severity and racial/ethnic and gender disparities from Omicron in the US is limited.
We performed a retrospective cohort study of a large, geographically diverse database of patient electronic health records (EHRs) in the US. The study population comprised 881,473 patients who contracted SARS-CoV-2 infection for the first time between 9/1/2021-1/16/2022, including 147,964 patients infected when Omicron predominated (Omicron cohort), 633,581 when Delta predominated (Delta cohort) and another 99,928 infected when the Delta predominated but just before the Omicron variant was detected in the US (Delta-2 cohort). We examined monthly incidence rates of COVID-19 infections stratified by age groups, gender, race and ethnicity, compared severe clinical outcomes including emergency department (ED) visits, hospitalizations, intensive care unit (ICU) admissions, and mechanical ventilation use between propensity-score matched Omicron and Delta cohorts stratified by age groups (0-4, 5-17, 18-64 and ≥ 65 years), and examined racial/ethnic and gender differences in severe clinical outcomes.
Among 147,964 infected patients in the Omicron cohort (average age: 39.1 years), 56.7% were female, 2.4% Asian, 21.1% Black, 6.2% Hispanic, and 51.8% White. The monthly incidence rate of COVID infections (new cases per 1000 persons per day) was 0.5-0.7 when Delta predominated, and rapidly increased to 3.8-5.2 when Omicron predominated. In January 2022, the infection rate was highest in children under 5 years (11.0) among all age groups, higher in Black than in White patients (14.0 vs. 3.8), and higher in Hispanic than in non-Hispanic patients (8.9 vs. 3.1). After propensity-score matching for demographics, socio-economic determinants of health, comorbidities and medications, risks for severe clinical outcomes in the Omicron cohort were significantly lower than in the Delta cohort: ED visits: 10.2% vs. 14.6% (risk ratio or RR: 0.70 [0.68-0.71]); hospitalizations: 2.6% vs. 4.4% (RR: 0.58 [0.55-0.60]); ICU admissions: 0.47% vs. 1.00% (RR: 0.47 [0.43-0.51]); mechanical ventilation: 0.08% vs. 0.3% (RR: 0.25 [0.20-0.31]). Similar reduction in disease severity was observed for all age groups. There were significant racial/ethnic and gender disparities in severe clinical outcomes in the Omicron cohort, with Black, Hispanic patients having more ED visits and ICU admissions than White and non-Hispanic patients, respectively and women had fewer hospitalization and ICU admission than men.
The incidence rate of COVID infection during the omicron predominant period (prevalence >92%) was 6-8 times higher than during the Delta predominant period that preceded it consistent with greater infectivity. The incidence rate was highest among those less than 5 years of age, and in Black and Hispanic patients. COVID infections occurring when the Omicron predominated were associated with significantly less frequent severe outcomes than in matched patients when the Delta variant predominated. There were significant racial, ethnic and gender disparities in severe clinical outcomes, with Black and Hispanic patients and men disproportionally impacted.
奥密克戎变异株出现后，美国及其他国家的新冠病毒感染和住院人数不断上升。目前，美国奥密克戎毒株的感染率、严重程度以及种族/民族和性别差异方面的数据有限。
我们对美国一个大型、地域多样的患者电子健康记录（EHR）数据库进行了回顾性队列研究。研究人群包括2021年9月1日至2022年1月16日期间首次感染新冠病毒的881473名患者，其中包括147964名在奥密克戎毒株占主导时感染的患者（奥密克戎队列）、633581名在德尔塔毒株占主导时感染的患者（德尔塔队列）以及另外99928名在德尔塔毒株占主导但在美国检测到奥密克戎变异株之前感染的患者（德尔塔-2队列）。我们按年龄组、性别、种族和民族对新冠病毒感染的月发病率进行了分层分析，比较了倾向评分匹配的奥密克戎和德尔塔队列（按年龄组0 - 4岁、5 - 17岁、18 - 64岁和≥65岁分层）之间的严重临床结局，包括急诊科就诊、住院、重症监护病房（ICU）入院和机械通气使用情况，并研究了严重临床结局中的种族/民族和性别差异。
在奥密克戎队列的147964名感染患者中（平均年龄：39.1岁），56.7%为女性，2.4%为亚洲人，21.1%为黑人，6.2%为西班牙裔，51.8%为白人。德尔塔毒株占主导时，新冠病毒感染的月发病率（每千人每日新增病例数）为0.5 - 0.7，奥密克戎毒株占主导时迅速升至3.8 - 5.2。2022年1月，所有年龄组中5岁以下儿童的感染率最高（11.0），黑人患者高于白人患者（14.0对3.8），西班牙裔患者高于非西班牙裔患者（8.9对3.1）。在对人口统计学、健康的社会经济决定因素以及合并症和用药情况进行倾向评分匹配后，奥密克戎队列中严重临床结局的风险显著低于德尔塔队列：急诊科就诊：10.2%对14.6%（风险比或RR：0.70[0.68 - 0.71]）；住院：2.6%对4.4%（RR：0.58[0.55 - 0.60]）；ICU入院：0.47%对1.00%（RR：0.47[0.43 - 0.51]）；机械通气：0.08%对0.3%（RR：）。所有年龄组均观察到疾病严重程度有类似降低。奥密克戎队列的严重临床结局存在显著的种族/民族和性别差异，黑人、西班牙裔患者的急诊科就诊和ICU入院次数分别多于白人和非西班牙裔患者，女性的住院和ICU入院次数少于男性。
奥密克戎毒株占主导时期（流行率>92%）的新冠病毒感染发病率比之前德尔塔毒株占主导时期高6 - 8倍，这与更高的传染性一致。发病率在5岁以下人群、黑人和西班牙裔患者中最高。奥密克戎毒株占主导时发生的新冠病毒感染与德尔塔变异株占主导时匹配患者相比，严重结局的发生频率显著更低。严重临床结局存在显著的种族、民族和性别差异，黑人和西班牙裔患者以及男性受到的影响尤为严重。
