Sex and Age Differences Found in Virus-Related ED Visits, Hospitalization in COPD

Significant age and sex differences were detected during an evaluation of emergency department (ED) visits and hospitalizations for respiratory viruses in patients with chronic obstructive pulmonary disease (COPD), asthma, and respiratory tract infections (RTIs).

The retrospective study, conducted in Canada and published in ERJ Open Research, is the first study to evaluate age and sex differences in the rates of ED visits and hospitalizations in this population, the authors said. It’s also the first to concurrently evaluate the association of respiratory viruses with the observed rates at the population level.

Viral infections often present to hospitals as RTIs or exacerbations related to COPD or asthma. The Canadian Respiratory Virus Detection Surveillance System report weekly percentages of positive tests for influenza A and B, respiratory syncytial virus, parainfluenza, adenovirus, human metapneumovirus, human rhinovirus, and coronavirus.

Knowledge about the influence of age and sex on ED visits and hospitalizations and the role that specific viruses play in outcomes is important. For instance, infants, children, and older adults are prone to have higher mortality rates from RTIs; males under the age of 15 are more likely to be hospitalized for asthma; and females with COPD have experienced more exacerbations and a rising mortality rate compared with males.

Previous research on COPD, asthma, and RTIs have often used small-sized cohorts of select groups of patients rather than population-based cohorts.

“Within a whole population where there is universal healthcare, and the reasons for ED visits and hospitalisations, along with individual daily virus rates, are being collected, a much broader perspective can be explored,” wrote the investigators.

The investigators analyzed data from the Respiratory Virus Detection Surveillance System for Ontario, Canada collected from 11 public health laboratories and 6 hospital laboratories between 2003 and 2013.

During this time frame, there were 817,141 ED visits for COPD, of which 260,665 (31.9%) resulted in hospital admission. Overall, 159,691 tests were performed in Ontario for the 8 reported respiratory viruses.

The rate of ED visits was higher among females with COPD who were between the ages of 15 and 5. However, the rate of increase by age was higher among male patients. This resulted in males over the age of 70 recording a higher daily ED visit rate than females.

The daily rate of hospitalizations increased with age for male and female patients. The rate was also similar between sexes for patients between the ages of 15 and 70 but was higher among men over 70 years of age.

The rate of ED visits to hospitalizations increased 7-fold from age 15 to 50 to 50 to 70. The rate increased 2-fold from the 50 to 70 age group to those aged 70 and above. Almost two-thirds of those over the age of 70 were hospitalized.

Influenza A was the respiratory virus most associated with ED visits among patients with COPD across all age groups and sexes. Influenza A was the most strongly associated with patients aged 50 to 70 and those over age 70. Among men and women, the association was similar until age 70, when the rate was higher among women.

The standardized beta-values for human rhinovirus among patients with COPD was small and similar across age groups and sexes but were consistently higher among women.

The study had several limitations, including that positive tests couldn’t be linked to specific ED visits and hospitalizations, that stratification based on age was limited, that there was a potential for misclassification of COPD diagnoses, and that there was a lack of access to information on comorbidities and medication usage.

Reference

Satia I, Adatia A, Cusack RP, et al. Influence of age, sex and respiratory viruses on the rates of emergency department visits and hospitalisations with respiratory tract infections, asthma and COPD. ERJ Open Res. May 24, 2021;7(2):00053-2021. doi: 10.1183/23120541.00053-2021