Pre-hospital antiplatelet therapy linked to lower COVID-19 death rates
Pre-hospital antiplatelet therapy, most commonly aspirin, was associated with significantly lower in-hospital mortality rates for COVID-19 patients, according to a study this week in the Journal of Thrombosis and Haemostasis.
The researchers matched 6,781 COVID-19 US patients who received antiplatelet therapy before hospital admission with 10,566 who did not receive antiplatelet therapy from February to September 2020. In this 1:1.6 ratio, data showed that those who received antiplatelet therapy had an in-hospital mortality rate of 18.9%, whereas those in the control group had a 21.5% in-hospital mortality rate (hazard ratio, 0.81; 95% confidence interval, 0.76 to 0.87). The antiplatelet therapy group also showed a lower rate of pulmonary embolism (2.2% vs 3.0%) but a higher rate of nosebleeds (0.9% vs 0.4%). No other clotting complications occurred.
Pre-matching, the total pool of patients was 34,675 people 50 or older across 90 US health systems (median age, 69 years). Almost 20% (6,781) had received pre-hospital antiplatelet therapy, with aspirin being the most common (83.9%), followed by clopidogrel (8.2%), and dual antiplatelet therapy occurred in 7.4%. About 30% of patients who didn't receive pre-hospital antiplatelet therapy later received it during their hospitalization.
"Importantly, most patients in the antiplatelet therapy arm received aspirin, which is a widely available medication that is inexpensive and has a well described risk profile," the researchers write. "Future studies are necessary to determine if mortality outcomes are different for P2Y12 antagonists, COX-1 inhibitors, or phosphodiesterase inhibitors."
Aug 29 J Thromb Haemos study
Study: High-risk allergy patients have low reaction rates to Pfizer vaccine
Of 429 patients considered to be high-risk for allergic reactions against the Pfizer/BioNTech COVID-19 vaccine, 98% had no allergic reaction, according to a JAMA Network Open study yesterday.
From Dec 27, 2020, to Feb 22, 2021, 8,102 Israeli patients with allergies applied to the COVID-19 vaccine referral center at the Sheba Medical Center near Tel Aviv. Overall, 85.0% were referred to receiving vaccination in regular settings, 1,219 received further assessment, and 429 (5.3%) were considered high-risk and received the Pfizer vaccine under medical supervision.
After the first dose, 97.9% of the high-risk group had no allergic reactions. Of the 218 who received their second dose during the study period, 98.2% had no allergic reactions.
Nine patients experienced allergic reactions after the first dose. Six had mild reactions that resolved with antihistamines during the observation period, and three had anaphylaxis within 10 to 20 minutes post-vaccination. The anaphylaxis resolved within 2 to 6 hours after adrenaline, antihistamines, an inhaled bronchodilator, and—for one patient—systemic glucocorticoids. None required hospitalization.
After the second dose, four patients had minor allergic reactions, which were treated with antihistamines and bronchodilators. Three of the four had experienced mild reactions after the first dose and had received premedication prior to the second.
"We enabled immunization of most patients with allergies by using a simple algorithm that included a referral center, a risk assessment questionnaire, and a safe environment for immunization of highly allergic patients with observation after immunization," write the researchers.
The high-risk group was 70.9% women, and the mean age was 52 years. Most had a history of anaphylaxis (63.2%), and many had multiple allergies (30.3%), had multiple drug allergies (32.9%), and carried an adrenaline syringe (22.1%).
"Interestingly, the low-risk allergy groups included many of those overrepresented in anaphylaxis reports in the Centers for Disease Control and Prevention's Vaccine Adverse Event Reporting System (VAERS): those who had chronic urticaria; sensitivity to foods, venoms, or aeroallergens; or nonanaphylactic reactions to drugs or contrast media," notes Elizabeth J. Phillips, MD, of Vanderbilt University, in a related commentary.
Aug 31 JAMA Netw Open study and commentary