Review Assesses Impact of Seasonality in COPD

Patients with chronic obstructive pulmonary disease (COPD) often have a significant disease burden that is particularly associated with the peak incidence of exacerbation events during winter months. A review assessed previous population studies that evaluated the impact of seasonality in COPD, emphasizing the importance of understanding how all factors impact patients and where interventions can be targeted.

The review used the Global Initiative for Chronic Obstructive Lung Disease (GOLD) Guidelines to define a COPD exacerbation as an acute event characterized by the worsening of a patient’s respiratory symptoms that is beyond normal variation and leads to a change in medication.

Read more about COPD.

One study that the authors reviewed demonstrated that the expression of anti-inflammatory genes was altered by the time of the year—highly expressed in June, July, and August in the northern hemisphere and raised in December, January, and February in the southern hemisphere.

“This seasonal variation in exacerbation incidence has a corresponding effect on hospital admissions in many different health care systems and is also associated with an increase in mortality,” explained the authors. “Therefore, a greater understanding of the factors that contribute to these seasonal increases in exacerbation rates should provide opportunities to protect patients and reduce the burden on already overstretched health care systems.”

Additionally, for environmental factors, the authors noted that in the general population extremes in temperature are typically associated with an increase in morbidity and mortality. As for COPD, the review found inconsistencies among a range of study results, which reflect the complexity of the associations among a variety of environmental factors and the infectious agent itself as well as the immune response from the host.

The authors explained how this review emphasizes that seasonal changes are multifactorial and require further research. The biology of a patient in response to seasonality needs to be better understood in order to provide better treatment and prevention options, according to the review.

“Research should be undertaken with a clear knowledge of the changing environmental conditions that patients experience. It is interesting to speculate as to how climate change will impact on these external factors, such as temperature, humidity, pollution levels, and local pathogen rates,” the authors said. “In this study, we have discussed the factors separately although they are all clearly interconnected; importantly, with growing climate extremes, there is a risk that this will impact on seasonal variations in exacerbations rates.”

The researchers concluded by explaining the need for large multicenter longitudinal studies to provide research context for healthcare modeling in order to offer new opportunities and to limit risk-associated exposures for patients with COPD.

Reference

Hicks A, Healy E, Sandeman N, Feelisch M, Wilkinson T. A time for everything and everything in its time — exploring the mechanisms underlying seasonality of COPD exacerbations. [published online September 5, 2018]. Int J Chron Obstruct Pulmon Dis. doi.org: 10.2147/COPD.S146015