Older adults with COVID-19 infection may be at increased risk of mortality and multiorgan dysfunction for more than 1 year following diagnosis, according to study results published in the Journal of Travel Medicine. 

Researchers conducted a retrospective cohort study among older adults from Hong Kong (HK) and the United Kingdom (UK) to investigate the long-term effects of COVID-19 infection. Study participants with polymerase chain reaction-confirmed COVID-19 infection were randomly matched against uninfected participants (controls) by age, sex, and index date. The index date for infected participants was defined as 21 days after the first positive COVID-19 test result.

Outcome measures included but were not limited to major cardiovascular disease (CVD), lung disease, neurocognitive decline, gastrointestinal disorders, kidney disease, deep vein thrombosis, hepatic complications, stroke, and all-cause mortality.

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Confounder impact was reduced with inverse probability treatment weighting for the UK cohort. Potential confounders included age, sex, Charlson Comorbidity Index scores, chronic kidney disease, respiratory disease, diabetes, CVD, history of cancer, and COVID-19 vaccination status. For the HK cohort, drug records were assessed and medication history was incorporated as an additional confounder. The association between COVID-19 infection and outcome measures was calculated via Cox proportional hazards regression, and incidence rates were determined via Poisson distribution. 

A total of 10,759 UK participants and 165,259 HK participants with COVID-19 infection were matched against 291,077 and 1,100,394 control participants, respectively. Participants’ baseline characteristics were similar between the groups. 

Participants with vs without COVID-19 diagnoses had higher incidence and risk of all-cause mortality in both the UK (hazard ratio [HR], 4.9; 95% CI, 4.4-5.4) and HK (HR, 2.5; 95% CI, 2.5-2.6) cohorts. 

Further analysis showed older adults with vs without COVID-19 diagnoses in both the UK and HK cohorts were at significantly increased risk for cardiovascular, respiratory, neurologic, psychiatric, gastrointestinal, renal, and hepatic complications.

The association between COVID-19 infection and increased risk of all-cause mortality was significantly greater among participants with severe vs nonsevere disease in both the UK (HR, 13.6; 95% CI, 9.0-20.5) and HK (HR, 37.8; 95% CI, 18.1-79.1) cohorts.

Limitations of this study include the observational design, potential confounding, and the possibility of asymptomatic infection among control participants.  

Based on these findings, “Infected patients in this age-group may benefit from appropriate monitoring of signs and symptoms of developing these disease complications in the long-term,” the researchers concluded.

This article originally appeared on Infectious Disease Advisor