In a recent study published in PLoS ONE, researchers evaluated the outcomes and identified risk factors associated with the development of ARDS (acute respiratory distress syndrome) after SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infections among young adults.
ARDS has been frequently reported as a complication of SARS-CoV-2 infections among patients requiring hospitalization and intensive care unit (ICU) admissions and has been associated with considerable morbidity and mortality. Age has been identified as a critical risk factor for ARDS development; however, data on post-coronavirus disease 2019 (COVID-19) ARDS among young adults are limited.
About the study
In the present retrospective cohort study, researchers performed a federated analysis comparing young (aged between 18 years and 49 years old) and older (aged >49 years) COVID-19 patients diagnosed with ARDS or without the illness to identify post-COVID-19 ARDS-associated risk factors. They also compared ARDS outcomes among the two age groups.
The international observational federated study, conducted in the period between 1 January 2020 and 28 February 28, 2021, utilizing EHRs (electronic health records) of individuals registered with 12 HS (healthcare systems) spanning over 241 hospitals and nine HS in the US (United States) and 43 hospitals and three HS in Europe that participated in the 4CE consortium (consortium for clinical characterization of coronavirus disease 2019 by electronic health records).
Across each HS, all individuals who were hospitalized one week prior to, and up to two weeks post-SARS-CoV-2-positive positive polymerase chain reaction (PCR) analysis reports were included in the analysis. The date of hospitalization during the period was regarded as the index date. Data were obtained till August 30, 2021, concerning the age, sex, admission duration, hospital discharge, medication history, and mortality.
ARDS diagnosis was based on the ICD-10 (international classification disease, tenth version) code, J80. Procedures associated with invasive-type mechanical ventilation or the insertion of endotracheal tubes were considered severe procedures. Medications such as anesthetics/sedatives or those prescribed for shock treatment were considered severe.
The participants were categorized into three groups- (i) ARDS group, comprising individuals with the J80 code, (ii) no severe group, comprising individuals without the J80 code and no severe medication/procedures history, and (iii) severe without ARDS group, comprising individuals without the J80 code, but with a positive history of severe medication/procedures.
For comorbid conditions categorized based on the Elixhauser index and for comparing complications among the two age groups, univariate analyses were performed, and risk ratios (RR) were estimated. Univariate analysis data obtained at each HS were aggregated for the random effect meta-analysis. In addition, sex and ARDS-associated comorbidities in the meta-univariable analysis were chosen for multivariate analyses.
The study comprised 75,377 hospitalized COVID-19 patients, of which 7,379 individuals, 56,519 individuals, and 11, 379 individuals, were categorized under the ARDS group, no severe group, and severe without ARDS group, respectively. Among the participants, 1001 18-year to 49-year-olds (eight percent of hospitalized young adult individuals) developed ARDS, compared to 10% of older-aged adults.
The 90-day mortality rates among young adults and older adults were 16% and 41%, respectively, and young ARDS patients presented with similar complication rates for infections in comparison to their older counterparts. Peptic ulcers (RR 3.7), paralysis (RR 3.8), obesity (RR 2.8), congestive cardiac failure (RR 2.2), valvular diseases (RR 1.9), diabetes (RR 1.9), chronic pulmonary diseases (RR 1.6), and hepatic diseases (RR 1.6) were related to greater ARDS risks.
Among young ARDS patients, the team observed an increased prevalence of comorbid conditions such as obesity (53%, n=533), diabetes (38%, n=382), and hypertension (32%, n=322). Patients aged 26 to 49 had an increased risk of developing ARDS compared to those aged 18 to 25 (RR 2.9), and men had a higher risk of developing ARDS (RR 1.7).
In comparison to older adults, young ARDS patients had a lower risk of developing the following complications: acute renal failure (RR 0.8), cardiac rhythm/conduction disorders (RR 0.6), fluid, electrolyte and acid-base balance disorders (RR 1.0), and stroke (RR 0.4). However, the risk of developing streptococcal sepsis (RR 1.6), and Streptococcus pneumonia-caused pneumonia (RR 1.8). Over 50% of the young ARDS patients had respiratory superinfections of bacterial etiology (n=538, 54%) during the period of their hospital stay.
Overall, the study findings showed that despite young ARDS patients representing a small percentage of hospitalized SARS-CoV-2-positive individuals with ARDS, they developed ARDS-associated poor outcomes with a noteworthy mortality rate. The study findings also identified risk factors associated with poor ARDS outcomes, which can aid in the early identification of, and provision of the most appropriate treatment to high-risk individuals.