Prophylactic anticoagulation to prevent venous thromboembolism (VTE) was associated with reduced 60-day mortality in patients with COVID-19 who were ill enough to require hospitalization, a new report shows.
In a cohort study of more than 1,300 hospitalized patients with COVID-19 infection across 30 hospitals in Michigan, both prophylactic- and therapeutic-dose anticoagulation were associated with reduced in-hospital mortality; however, at 60 days, only prophylactic-dose anticoagulation remained associated with lower mortality.
And adherence was key; nonadherence, or missing 2 days or more of anticoagulation, was linked to more deaths at 60 days.
The findings, which were published online June 11 in JAMA Network Open, are final proof that a prophylactic anticoagulation strategy for the hospitalized COVID population is, indeed, the right one, Valerie M. Vaughn, MD, director of hospital medicine research at the University of Utah, Salt Lake City, said in an interview.
“We’ve probably always known that patients with COVID need prophylaxis for VTE, but we found that early on, unfortunately, that wasn’t being done,” Dr. Vaughn said.
“Now, we see that prophylactic rates have increased. We always knew to use anticoagulation prophylactically in patients who were hospitalized with infection because of their risk for VTE, so this study just drives home that proper adherence to an anticoagulation protocol improves mortality,” she said.
Dr. Vaughn was on the front lines when COVID-19 came to Michigan, where the research was conducted.
“We probably should have been anticoagulating from the get-go, but you have to remember that in the early days of COVID, the hospitals in Michigan were being overwhelmed. They didn’t have PPE. They were taking care of patients outside of their typical hospital beds or setting up field hospitals,” she said. “It was not quite as bad as New York, but at the University of Michigan, we set up four or five ICUs outside of our normal care.”
They also converted the top floor of their pediatric hospital into an ICU to take care of patients with COVID during the first surge, she added. “We didn’t know much about this disease, but faced with this influx of patients, many of whom were dying with blood clots, we had to do something.”
Some hospitals began prophylactically anticoagulating their patients, but others hesitated before adopting the strategy. “But now we feel confident that prophylactic anticoagulation, done according to the right protocol, with no interruptions in the treatment, is beneficial,” Dr. Vaughn said.
“Prophylactic dose anticoagulation is typically given by an injection under the skin, but a lot of times, I’ve had patients tell me they feel like a human pin cushion and have all these bruises from being stuck with needles every day, which I can totally relate to,” she said.
“It is important for us as clinicians to explain that we’re having to poke our patients because it is good for them and will help them fight COVID,” she added. “Also having the once-a-day option is going to be a lot better for adherence, and adherence to the protocol, not missing any days, is key to the better outcome.”
Dr. Vaughn and her team reviewed the charts of 1,351 patients (48% women, 49% Black, median age 64 [range 52-75]) who were hospitalized throughout Michigan during the first several months of the COVID-19 pandemic, from March to June 2020.
Only 18 patients (1.3%) had a confirmed VTE and 219 patients (16.2%) received treatment-dose anticoagulation.
The researchers noted that use of treatment-dose anticoagulation without imaging ranged from 0% to 29% across hospitals and increased significantly over time.
Of the 1,127 patients who received anticoagulation, 392 (34.8%) missed 2 days or more of prophylaxis.
In addition, there were varying rates of missed prophylaxis among the hospitals, from 11% to 61%, but these rates decreased markedly over time.
Missed doses were associated with a higher 60-day mortality (adjusted hazard ratio, 1.31; 95% confidence interval, 1.03-1.67), but not in-hospital mortality (aHR, 0.97; 95% CI, 0.91-1.03).
Compared with no anticoagulation, receiving any dose of anticoagulation was associated with lower in-hospital mortality.
However, only prophylactic-dose anticoagulation remained associated with lower mortality at 60 days. The adjusted hazard ratio for prophylactic-dose anticoagulation was 0.71 (95% CI, 0.51-0.90), compared with 0.92 (95% CI, 0.63-1.35) for treatment-dose anticoagulation.