Among people with COVID-19, those with systemic autoimmune rheumatic diseases had an elevated 30-day risk of hospitalization, ICU admission, need for mechanical ventilation, and acute kidney injury, compared to a group without rheumatic diseases at 4 months in a match-controlled study.

Dr. Kristin D'Silva, a rheumatology fellow at Massachusetts General Hospital in Boston

Dr. Kristin D'Silva

When investigators expanded the study to 6 months, the difference in need for mechanical ventilation disappeared. However, relative risk for venous thromboembolism (VTE) emerged as 74% higher among people with COVID-19 and with rheumatic disease, said Kristin D’Silva, MD, who presented the findings during a plenary session at the virtual annual meeting of the American College of Rheumatology. She noted that rheumatic disease itself could contribute to VTE risk.

Comorbidities including hypertension, diabetes, and asthma were more common among people with systemic autoimmune rheumatic diseases (SARDs). After adjustment for comorbidities, “the risks of hospitalization and ICU admission were attenuated, suggesting comorbidities are likely key mediators of the increased risk of severe COVID-19 outcomes observed in SARDs patients versus comparators,” Dr. D’Silva, a rheumatology fellow at Massachusetts General Hospital in Boston, said in an interview.

“The risk of venous thromboembolism persisted even after adjusting for comorbidities,” Dr. D’Silva said. Patients with SARDs should be closely monitored for VTE during COVID-19 infection, she added. “Patients with significant cardiovascular, pulmonary, and metabolic comorbidities should be closely monitored for severe COVID-19.”

At the same time, a systematic review of 15 published studies revealed a low incidence of COVID-19 infection among people with rheumatic disease. Furthermore, most experienced a mild clinical course and low mortality, Akhil Sood, MD, said when presenting results of his poster at the meeting.

Underlying immunosuppression, chronic inflammation, comorbidities, and disparities based on racial, ethnic, and socioeconomic status could predispose people with rheumatic disease to poorer COVID-19 outcomes. However, the risks and outcomes of COVID-19 infection among this population “are not well understood,” said Dr. Sood, a second-year resident in internal medicine at the University of Texas Medical Branch in Galveston.

Elevated risks in match-controlled study

Dr. D’Silva and colleagues examined a COVID-19 population and compared 716 people with SARDs and another 716 people from the general public at 4 months, as well as 2,379 people each in similar groups at 6 months. They used real-time electronic medical record data from the TriNetX research network to identify ICD-10 codes for inflammatory arthritis, connective tissue diseases, and systemic vasculitis. They also used ICD-10 codes and positive PCR tests to identify people with COVID-19.

Mean age was 57 years and women accounted for 79% of both groups evaluated at 4 months. Those with SARDs were 23% more likely to be hospitalized (relative risk, 1.23; 95% confidence interval, 1.01-1.50). This group was 75% more likely to be admitted to the ICU (RR, 1.75; 95% CI, 1.11-2.75), 77% more likely to require mechanical ventilation (RR, 1.77; 95% CI, 1.06-2.96), and 83% more likely to experience acute kidney injury (RR, 1.83; 95% CI, 1.11-3.00).

Risk of death was not significantly higher in the SARDs group (RR, 1.16; 95% CI, 0.73-1.86).

When Dr. D’Silva expanded the study to more people at 6 months, they added additional 30-day outcomes of interest: renal replacement therapy, VTE, and ischemic stroke. Risk of need for renal replacement therapy, for example, was 81% higher in the SARDs group (RR, 1.81; 95% CI, 1.07-3.07). Risk of stroke was not significantly different between groups.The improvement in mechanical ventilation risk between 4 and 6 months was not completely unexpected, Dr. D’Silva said. The relative risk dropped from 1.77 to 1.05. “This is not particularly surprising given national trends in the general population reporting decreased severe outcomes of COVID-19 including mortality as the pandemic progresses. This is likely multifactorial including changes in COVID-19 management (such as increasing use of nonintubated prone positioning rather than early intubation and treatments such as dexamethasone and remdesivir), decreased strain on hospitals and staffing compared to the early crisis phase of the pandemic, and higher testing capacity leading to detection of milder cases.”

When the 6-month analysis was further adjusted for comorbidities and a history of prior hospitalization within 1 year, only risk for acute kidney injury and VTE remained significant with relative risks of 1.33 and 1.60, respectively, likely because comorbidities are causal intermediates of COVID-19 30-day outcomes rather than confounders.

When asked to comment on the results, session comoderator Victoria K. Shanmugam, MD, said in an interview that the study “is of great interest both to rheumatologists and to patients with rheumatic disease.”

Dr. Victoria K. Shanmugam, Director of the Division of Rheumatology at The George Washington University in Washington, D.C.

Dr. Victoria K. Shanmugam

The higher risk of hospitalization, ICU admission, mechanical ventilation, acute kidney injury, and heart failure “is an important finding with implications for how our patients navigate risk during this pandemic,” said Dr. Shanmugam, director of the division of rheumatology at George Washington University in Washington.

Lower risks emerge in systematic review

The 15 observational studies in the systematic review included 11,815 participants. A total of 179, or 1.5%, tested positive for COVID-19.

“The incidence of COVID-19 infection among patients with rheumatic disease was low,” Dr. Sood said.

Within the COVID-19-positive group, almost 50% required hospitalization, 10% required ICU admission, and 8% died. The pooled event rate for hospitalization was 0.440 (95% CI, 0.296-0.596), while for ICU admission it was 0.132 (95% CI, 0.087-0.194) and for death it was 0.125 (95% CI, 0.082-0.182).

Different calculations of risk

The two studies seem to offer contradictory findings, but the disparities could be explained by study design differences. For example, Dr. D’Silva’s study evaluated a population with COVID-19 and compared those with SARDs versus a matched group from the general public. Dr. Sood and colleagues assessed study populations with rheumatic disease and assessed incidence of SARS-CoV-2 infection and difference in outcomes.

“We are asking very different questions,” Dr. D’Silva said.

“The study by D’Silva et al. was able to account for different factors to reduce confounding,” Dr. Sood said, adding that Dr. D’Silva and colleagues included a high proportion of minorities, compared with a less diverse population in the systematic review, which featured a large number of studies from Italy.

The authors of the two studies had no relevant financial disclosures to report.

SOURCES: D’Silva K et al. Arthritis Rheumatol. 2020;72(suppl 10): Abstract 0430, and Sood A et al. Arthritis Rheumatol. 2020;72(suppl 10): Abstract 0008.