Comorbid conditions

COVID-19 Roundup: New Onset Alzheimer Disease, Elevated Risk for Thrombotic Diseases, and More

Higher Risk of New Onset Alzheimer Disease After COVID-19 Infection in Older Individuals1

Individuals aged 65 years and older who’ve had a COVID-19 infection may be at a considerably greater risk—as much as 50% to 80% higher than a control group—of developing new onset Alzheimer disease (AD) within a year, according to a new study.

Researchers conducted a retrospective cohort study utilizing data from de-identified electronic health records from more than 6 million older adults who had medical encounters between February 2020 to May 2021 for non-COVID-19 reasons and had no prior diagnosis of AD.

The findings revealed that before propensity score matching the risk for developing AD in older individuals nearly doubled (0.35% to 0.68%) during a 1-year period following a COVID-19 infection. After propensity-score matching, the COVID-19 cohort had augmented risk for new diagnosis of AD compared with matched non-COVID-19 cohort (HR 1.69, 95% CI; 1.53 – 1.72) particularly in individuals aged 85 years and older and in women.

The researchers noted that it is uncertain whether COVID-19 triggers new development of AD or accelerates its emergence. They concluded that confirmation from other data resources, longer-term follow-up, understanding underlying mechanisms, and investigating other types of dementia is warranted.

High Risk Remains for Vascular Events After Infection2

Although the relative incidence of vascular events increases following COVID-19 infection, it decreases more swiftly for arterial thromboses (ATs) than venous thromboembolic events (VTEs), according to new cohort study involving 48 million adults in England and Wales.

Of the study cohort, 125,985 were hospitalized and 1,319,789 were not hospitalized within 28 days of COVID-19 diagnosis. In England, there were 260,279 first ATs and 59,421 first VTEs during 41.6 million person-years of follow-up. When comparing individuals hospitalized with COVID-19 vs those not hospitalized, the adjusted hazard ratios were greater for longer periods following diagnosis for Black vs White individuals and among those without a previous event vs those with a previous event.

The estimated whole-population increases in risk of ATs and VTEs 49 weeks after COVID-19 diagnosis were 0.5% and 0.25%, respectively, corresponding to 7,200 and 3,500 additional events after 1.4 million COVID-19 diagnoses.

The authors concluded, “These results support policies to prevent severe COVID-19 by means of COVID-19 vaccines, early review after discharge, risk factor control, and use of secondary preventive agents in high-risk patients.”

COVID-19 Vaccines Effective in Patients Taking Immunosuppressive Drugs3

Individuals taking immunosuppressive disease modifying antirheumatic drugs (DMARDs), biologic DMARDs, or glucocorticoids are at considerably greater risk of hospitalization due to COVID-19 than the general population. Nevertheless, the mRNA-1273 and BNT162b2 vaccines remain effective within this patient population group, according to findings from a retrospective study.

Researchers sought to evaluate the relationship between immunosuppressive medications, mRNA vaccination, omicron infection, and severe COVID-19 outcomes, including hospitalization, ICU admission, and death.

Results revealed that among the 168,414 participants receiving immunosuppressants, 3 doses of BNT162b2 had a vaccine effectiveness of 50% (95% CI 31 – 64; p < .0001) and 3 doses of mRNA-1273 had a vaccine effectiveness of 60% (42 – 73; p < .0001) against SARS-CoV-2 infection. Moreover, 3 doses of either vaccine had an effectiveness of 87% (95% CI 73 – 93; p < .0001) against hospitalization due to COVID-19. Receipt of immunosuppressive DMARDs or glucocorticoids and a history of organ or bone marrow transplantation were linked with augmented risk of hospitalization due to COVID-19 compared with those who had not received immunosuppressive medications or transplant.

New Onset Atrial Fibrillation in Patients Hospitalized With COVID-194

New onset atrial fibrillation (AF) developed in 1 in 20 patients hospitalized with COVID-19 and was strongly correlated with increased in-hospital mortality and major adverse cardiovascular events, according to a new study.  

Utilizing data from the American Heart Association’s COVID-19 Cardiovascular Disease Registry, researchers examined patients without a history of AF who were hospitalized for COVID-19. The primary and secondary outcomes were in-hospital mortality and major adverse cardiovascular events, including cardiovascular death, myocardial infarction, stroke, cardiogenic shock, and heart failure.

The authors found that of the 30,999 total patients, 27,851 had no history of AF. Moreover, 1517 (5.4%) developed new-onset AF during their index hospitalization. New-onset AF was correlated with greater rates of death (45.2% vs 11.9%) and major adverse cardiovascular events (MACE) (23.8% vs 6.5%). The unadjusted hazard ratio for mortality was 1.99 (95% CI, 1.81 – 2.18) and for MACE was 2.23 (95% CI, 1.98 – 2.53) for patients with new onset AF versus without new-onset AF.

“Our findings do not support a causal association between incident [AF] and mortality among patients hospitalized with COVID-19,” the authors wrote. “However, an attenuated association was found between new-onset AF and MACE in the fully adjusted model. These findings predominantly suggest that [AF] is a marker of disease severity, though specific [AF]-directed therapies such as rhythm control and anticoagulation need to be further investigated to assess the impact on MACE event occurrences.”


—Yvette C Terrie, BS, Pharm, R.Ph.



  1. Wang L, Davis PB, Volkow ND, Berger NA, Kaelber DC, Xu R. Association of COVID-19 with New-Onset Alzheimer's Disease. J Alzheimers Dis. 2022;89(2):411-414. doi:10.3233/JAD-220717
  2. Knight R, Walker V, Ip S, et al. Association of COVID-19 With Major Arterial and Venous Thrombotic Diseases: A Population-Wide Cohort Study of 48 Million Adults in England and Wales. Circulation. 2022;146(12):892-906. doi:10.1161/CIRCULATIONAHA.122.060785
  3. Risk M, Hayek SS, Schiopu E, et al. COVID-19 vaccine effectiveness against omicron (B.1.1.529) variant infection and hospitalization in patients taking immunosuppressive medications: a retrospective cohort study. Lancet Rheumatol. 2022;10.1016/S2665-9913(22)00216-8. doi:10.1016/S2665-9913(22)00216-8
  4. Rosenblatt AG, Ayers CR, Rao A, et al. New-Onset Atrial Fibrillation in Patients Hospitalized With COVID-19: Results From the American Heart Association COVID-19 Cardiovascular Registry. Circ Arrhythm Electrophysiol. 2022;15(5):e010666. doi:10.1161/CIRCEP.121.010666