Hospitalizations, ED Visits for COPD and Asthma Increase Under Certain Weather Conditions

Hospitalizations and emergency department (ED) visits for patients with chronic obstructive pulmonary disease (COPD) and asthma increased as meteorological factors and air pollutants changed, according to a recent study.

The results, published in the Korean Journal of Internal Medicine, show that environmental factors, including bouts of low temperature, low humidity, a large temperature difference, high atmospheric pressure, high wind speed, and high concentrations of particulate matter with aerodynamic diameters less than 10 mcm (PM₁₀) and ozone (O₃), can have adverse effects on asthma and COPD disease course, especially in elderly patients.

“Individualized treatment and management has recently been emphasized for asthma and COPD; such treatment should take sex, age, and environmental factors into account,” wrote the investigators.

Weather changes and air pollutant exposure are known to aggravate chronic respiratory conditions, including asthma and COPD, and cause exacerbations, leading to higher health care utilization and medical costs. However, the impacts of environmental factors on COPD and asthma have not been compared prior to this study.

Data on hospitalizations and ED visits were collected from the Korea Health Insurance Review and Assessment database. The data included medical care utilization patterns from 2007 to 2013 of patients with COPD or asthma from Busan, Ulsan, and Gyeongsangnam-do, Republic of Korea.

Meteorological information for place of residence was retrieved from the nearest monitoring station and provided by the Korean Meteorological Administration. Because O₃ levels can vary seasonally, high levels of O₃ were defined by the expected levels from May to September of each year.

Of the medical care visits during the study period, 147,910 were attributed to asthma and 229,133 were for COPD management. Patients were mostly women (asthma, 54.8%; COPD, 55.6%). Busan accounted for the largest proportion of visits resulting from COPD complications.

Over the course of the study, the mean (SD) temperature was 14.1℃ (9.1℃), the mean (SD) temperature difference was 9.3℃ (4.1℃), and the mean (SD) wind speed was 2.3 (1.4) m/sec. Additionally, the mean (SD) relative humidity was 63.1% (17%) and the mean (SD) atmospheric pressure was 1008.9 (8.4) hPa.

Study results showed that a decrease in mean temperature by 1℃ was associated with increases in asthma- and COPD-related hospitalization of 1.2% and 1.7%, respectively, and increases in ED visits of 1.6% for asthma and 2.7% for COPD.

Similarly, an increase in temperature difference of 1℃ resulted in a rise in hospitalizations of 2.7% and 1.8% and ED visits of 1.9% and 2.5% for asthma and COPD, respectively.

When the relative humidity decreased by 10%, hospital admissions and ED visits increased by 4% and 6%, respectively, for asthma and by 5% and 10%, respectively, for COPD. When levels of atmospheric pressure were elevated by 10 hPa, hospitalizations and ED visits increased by 7% and 16% for asthma and 10% and 27% for COPD.

Elevated wind speeds of 1 m/sec were associated with a 4% increase in hospitalizations and a 2.4% increase in ED visits due to COPD. However, wind speed was not associated with asthma-related medical care use.

A 10 mcm/m³ increase in PM10 was related to a 1% rise in medical care visits for both respiratory conditions. Each increase in O₃ level by 10 ppb between May and September was associated with increased ED visits by 2% for asthma and 5% for COPD.

Elderly patients had the highest risk of increased medical care use, and the effects among older patients were found to be greater for COPD than for asthma. Additionally, whereas ED care was more prevalent among female patients, male patients had a higher prevalence of hospitalizations.

Investigators’ limited use of O₃ levels and lack of information on daily environmental factors were identified as study limitations. Additionally, each medical care visit was treated as a discrete event, and the study did not take into account the potential for multiple visits to be attributable to 1 patient.

Reference

Jo EJ, Choi MH, Kim CH, et al. Patterns of medical care utilization according to environmental factors in asthma and chronic obstructive pulmonary disease patients. Korean J Intern Med. Published online February 10, 2021. doi:10.3904/kjim.2020.168