Sedentary Patients With COPD Have a Higher Risk of Emergency Department Visits, Study Says

Patients with chronic obstructive pulmonary disease (COPD) have a higher risk of emergency department (ED) visits or hospitalizations, with the highest risk among sedentary patients, according to a study published in BMJ Open Respiratory Research.

Patients with COPD are typically characterized by lower physical activity (PA); lower PA levels are associated with both decreased lung function and accelerated deterioration of lung function. Consequently, PA levels in patients with COPD are the strongest predictor of all-cause mortality and an independent predictor of acute exacerbation hospitalization risk and premature death.

Despite this, little information is available on the association between PA levels assessed by metabolic equivalents (METs) and hospitalization risk in patients with COPD. Therefore, the researchers aimed to quantify PA levels and evaluate their effects on all-cause and respiratory ED visits or hospitalizations in Korean subjects with and without COPD.

The chronic obstructive pulmonary disease (COPD) group with reduced physical activity (PA) has a higher risk of emergency department (ED) visits or hospitalizations. | Image Credit: rawpixel.com - stock.adobe.com

To do so, the researchers used the Health Screening Examination data from the National Health Insurance Service-National Sample Cohort, a population-based retrospective cohort that includes a 2.2% representative sample of Korean citizens. This database collects health data regarding major and minor diagnoses using the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) codes, health examination findings, and drug prescriptions.

The study’s primary exposure was PA, and PA intensity was measured using self-reported questionnaires; the survey included 3 questions on PA frequency and duration during the prior 7 days. Additionally, they calculated PA levels by assigning ratings of 2.9, 4.0, and 7.0 METs for light-intensity, moderate-intensity, and vigorous-intensity PAs, respectively.

Also, the main outcomes of the study were all-cause and respiratory ED visits or hospitalizations. The researchers explained that they calculated the respective incidence of ED visits or hospitalizations by dividing the number of ED visits or hospitalizations by the sum of the follow-up duration, presented as the rate per 1000 person-years (PY). Lastly, the covariates considered included body mass index (BMI), smoking status, alcohol consumption, and COPD-related comorbidities.

From the database, the researchers created 2 cohorts: the COPD cohort and the non-COPD cohort. The COPD cohort consisted of 3308 patients with at least an ICD-10 code for COPD and COPD-related medications within 1 year of health examination. Conversely, the non-COPD cohort consisted of 293,358 patients without ICD-10 codes for COPD. They noted that those with COPD were associated with being of older age, underweight, ex-smokers, lower income, and having comorbidities such as diabetes, asthma, and hypertension (P < .001 for all variables).

The researchers found the median PA level to be 414 METS-min/week (IQR, 87-728) for all patients. More specifically, they reported that the PA level was significantly lower in the COPD cohort (280 METS-min/week; IQR, 0-609) than in the non-COPD cohort (414 METS-min/week; IQR, 87-728) (P < .001). This demonstrated a greater proportion of sedentary activity in the COPD cohort than in the non-COPD cohort (35.4% vs 24.1%; P < .001).

Also, the all-cause ED visit or hospitalization rate (/1000 PY) was significantly higher in the COPD cohort than in the control cohort (P < .01 for all PA groups). Compared with the non-COPD group with PA greater than or equal to 1500 METS-min/week, the researchers reported that the COPD group had a higher risk of all-cause ED visit and hospitalization across all PA levels; the highest risk was found in the sedentary group (adjusted hazard ratio [aHR], 1.70; 95% CI, 1.59-1.81). Conversely, the continuous PA model showed that a 500 METs-min/week increase in PA was associated with reduced all-cause ED visits or hospitalizations by 10% (aHR, 0.92; 95% CI, 0.88-0.96) in the COPD cohort and 3% (aHR, 0.98; 95% CI, 0.97-0.98) in the non-COPD cohort.

Similarly, researchers found the respiratory ED visit or hospitalization rate (/1000 PY) to be significantly greater in the COPD cohort across all PA levels (P < .01 for all PA groups). Compared with the non-COPD cohort with PA greater than or equal to 1500 METs-min/week, the COPD cohort had a higher risk of all-cause ED visits and hospitalizations, the highest risk being in the sedentary group (aHR, 5.45; 95% CI, 4.86-6.12). Lastly, the continuous PA model showed that a 500 METs-min/week increase in PA was associated with reduced respiratory ED visits or hospitalizations by 14% in the COPD cohort (aHR, 0.87; 95 CI, 0.82-0.93) and 7% in the non-COPD cohort (aHR, 0.94; 95% CI, 0.92-0.95).

The researchers acknowledged their study’s limitations, one being that they evaluated PA levels using questionnaires, so potential recall bias was a major limitation. Also, despite statistical adjustments to address potential confounding factors, some additional confounding factors may not have been addressed. Despite these limitations, the researchers made suggestions for future improvements and research based on their findings.

“Increasing PA would be important for improving long-term outcomes in patients with COPD in Korea,” the authors concluded. “Confirmative future prospective studies are needed on whether assessing and modifying PA levels could reduce ED visit or hospitalization in COPD.”

Reference

Yang B, Lee H, Ryu J, et al. Impacts of regular physical activity on hospitalisation in chronic obstructive pulmonary disease: a nationwide population-based study. BMJ Open Respir Res. 2024;11(1):e001789. doi:10.1136/bmjresp-2023-001789