A New High Affinity Hemoglobin Variant: Hb San Francisco-KP (HBB: c.104T>C).

The evaluation of erythrocytosis can fail to detect hemoglobin (Hb) variants if a thorough and systemic investigation is not undertaken. Here we report the identification of a novel high-oxygen affinity Hb that was previously misclassified as polycythemia vera (PV). Given that treatment recommendations can vary significantly based on the etiology of erythrocytosis, familiarity with reference laboratories and their methodologies is of crucial importance to conducting a precise consultation, as in the case of our Hb variant, named Hb San Francisco-KP [ß34(B16)Val→Ala, HBB: c.104T>C] for the city and medical center where it was discovered. The Mayo Clinic's (Rochester, MN, USA) Erythrocytosis Evaluation (REVE) panel was instrumental in establishing a final diagnosis. Of note, the patient's clinical response to phlebotomy distinguishes this subtype from many of the other high affinity Hbs where the erythrocytosis is primarily compensatory and not in need of venesection.

Expanding outpatient management of low-risk pulmonary embolism to the pregnant population: a case series.

Background: Outpatient treatment of pregnant patients with acute pulmonary embolism (PE) is recommended by some obstetric and haematology societies but has not been described in the literature. Little is known about patient selection and clinical outcomes. Case summary: We report two cases of pregnant patients diagnosed with acute PE. The first, at 9 weeks of gestational age, presented to the emergency department with 12 h of pleuritic chest pain and was diagnosed with segmental PE. She was normotensive and tachycardic without evidence of right ventricular dysfunction. She received multispecialty evaluation, was deemed suitable for outpatient management, and, after 12 h of monitoring, was discharged home on enoxaparin with close follow-up. The second case, at 30 weeks of gestational age, presented to obstetrics clinic with 3 days of dyspnoea. Vital signs were normal except for tachycardia. She was referred to labour and delivery, where she was diagnosed with segmental PE. Her vital signs were stable, and she had no evidence of right ventricular dysfunction. After 6 h of monitoring, she was discharged home on enoxaparin with close follow-up. Neither patient developed antenatal complications from their PE or its treatment. Discussion: This case series is the first to our knowledge to describe patient and treatment characteristics of pregnant patients with acute PE cared for as outpatients. We propose a definition for this phenomenon and discuss the benefits of and provisional selection criteria for outpatient PE management, while engaging with professional society guidelines and the literature. This understudied practice warrants further research.

Assessment of the Risk of Venous Thromboembolism in Nonhospitalized Patients With COVID-19.

Importance: Patients hospitalized with COVID-19 have higher rates of venous thromboembolism (VTE), but the risk and predictors of VTE among individuals with less severe COVID-19 managed in outpatient settings are less well understood. Objectives: To assess the risk of VTE among outpatients with COVID-19 and identify independent predictors of VTE. Design, Setting, and Participants: A retrospective cohort study was conducted at 2 integrated health care delivery systems in Northern and Southern California. Data for this study were obtained from the Kaiser Permanente Virtual Data Warehouse and electronic health records. Participants included nonhospitalized adults aged 18 years or older with COVID-19 diagnosed between January 1, 2020, and January 31, 2021, with follow-up through February 28, 2021. Exposures: Patient demographic and clinical characteristics identified from integrated electronic health records. Main Outcomes and Measures: The primary outcome was the rate per 100 person-years of diagnosed VTE, which was identified using an algorithm based on encounter diagnosis codes and natural language processing. Multivariable regression using a Fine-Gray subdistribution hazard model was used to identify variables independently associated with VTE risk. Multiple imputation was used to address missing data. Results: A total of 398 530 outpatients with COVID-19 were identified. The mean (SD) age was 43.8 (15.8) years, 53.7% were women, and 54.3% were of self-reported Hispanic ethnicity. There were 292 (0.1%) VTE events identified over the follow-up period, for an overall rate of 0.26 (95% CI, 0.24-0.30) per 100 person-years. The sharpest increase in VTE risk was observed during the first 30 days after COVID-19 diagnosis (unadjusted rate, 0.58; 95% CI, 0.51-0.67 per 100 person-years vs 0.09; 95% CI, 0.08-0.11 per 100 person-years after 30 days). In multivariable models, the following variables were associated with a higher risk for VTE in the setting of nonhospitalized COVID-19: age 55 to 64 years (HR 1.85 [95% CI, 1.26-2.72]), 65 to 74 years (3.43 [95% CI, 2.18-5.39]), 75 to 84 years (5.46 [95% CI, 3.20-9.34]), greater than or equal to 85 years (6.51 [95% CI, 3.05-13.86]), male gender (1.49 [95% CI, 1.15-1.96]), prior VTE (7.49 [95% CI, 4.29-13.07]), thrombophilia (2.52 [95% CI, 1.04-6.14]), inflammatory bowel disease (2.43 [95% CI, 1.02-5.80]), body mass index 30.0-39.9 (1.57 [95% CI, 1.06-2.34]), and body mass index greater than or equal to 40.0 (3.07 [1.95-4.83]). Conclusions and Relevance: In this cohort study of outpatients with COVID-19, the absolute risk of VTE was low. Several patient-level factors were associated with higher VTE risk; these findings may help identify subsets of patients with COVID-19 who may benefit from more intensive surveillance or VTE preventive strategies.

COVID-19 and Risk of VTE in Ethnically Diverse Populations.

BACKGROUND: Limited existing data suggest that the novel COVID-19 may increase risk of VTE, but information from large, ethnically diverse populations with appropriate control participants is lacking. RESEARCH QUESTION: Does the rate of VTE among adults hospitalized with COVID-19 differ from matched hospitalized control participants without COVID-19? STUDY DESIGN AND METHODS: We conducted a retrospective study among hospitalized adults with laboratory-confirmed COVID-19 and hospitalized adults without evidence of COVID-19 matched for age, sex, race or ethnicity, acute illness severity, and month of hospitalization between January 2020 and August 2020 from two integrated health care delivery systems with 36 hospitals. Outcomes included VTE (DVT or pulmonary embolism ascertained using diagnosis codes combined with validated natural language processing algorithms applied to electronic health records) and death resulting from any cause at 30 days. Fine and Gray hazards regression was performed to evaluate the association of COVID-19 with VTE after accounting for competing risk of death and residual differences between groups, as well as to identify predictors of VTE in patients with COVID-19. RESULTS: We identified 6,319 adults with COVID-19 and 6,319 matched adults without COVID-19, with mean ± SD age of 60.0 ± 17.2 years, 46% women, 53.1% Hispanic, 14.6% Asian/Pacific Islander, and 10.3% Black. During 30-day follow-up, 313 validated cases of VTE (160 COVID-19, 153 control participants) and 1,172 deaths (817 in patients with COVID-19, 355 in control participants) occurred. Adults with COVID-19 showed a more than threefold adjusted risk of VTE (adjusted hazard ratio, 3.48; 95% CI, 2.03-5.98) compared with matched control participants. Predictors of VTE in patients with COVID-19 included age ≥ 55 years, Black race, prior VTE, diagnosed sepsis, prior moderate or severe liver disease, BMI ≥ 40 kg/m2, and platelet count > 217 k/µL. INTERPRETATION: Among ethnically diverse hospitalized adults, COVID-19 infection increased the risk of VTE, and selected patient characteristics were associated with higher thromboembolic risk in the setting of COVID-19.