Disproportionate decline in admissions for exacerbated COPD during the COVID-19 pandemic

1. Introduction

Patients with chronic obstructive pulmonary disease (COPD) may represent a particularly vulnerable group for infections with COVID-19. Less favorable outcomes might be common among COPD patients with COVID-19 infections [1]. Social containment measures have been implemented to address the COVID-19 pandemic. However, such measures have collaterally translated into a significant decrease in hospitalization rates of patients with stroke [2] and myocardial infarction [3]. Whether a similar association might also be seen among COPD patients is unclear, and recent population-based data are scarce. We therefore investigated current hospital admission rates for exacerbated COPD, and compared our findings with prior COPD admission rates as well as current admission rates for myocardial infarction and stroke at our institution.

2. Methods

The University Hospital Augsburg provides healthcare for a population of more than 546,500 inhabitants, whose sociodemographic characteristics are highly representative for the German population [4]. We retrospectively searched the institutional database for patients with exacerbated COPD (ICD-10-GM: J44.0, J44.1), stroke (ICD-10-GM: I63), and myocardial infarction (ICD-10-GM: I21), hospitalized between 01. December 2017 and 01. May 2020. Monthly admission rates were available for our review. Given that the first case of COVID-19 in Germany was confirmed on 27. January 2020, study period was defined from 01. February to 01. May 2020. We compared admission rates between the study period and a corresponding period during the two previous years (01. February to 01. May 2018/2019). Changes in admission rates were assessed by calculating admission rate ratios, dividing monthly admission rates during the study period by corresponding monthly admission rates during the two previous years. Differences in admission rates and admission rate ratios were analyzed by the unpaired Student's t-test. Statistical analyses were performed using Prism statistical software (Prism 7.0a; GraphPad Software Inc., San Diego, CA, USA). The significance level was set at p ≤ 0.05.

3. Results

184 patients were hospitalized for exacerbated COPD during the study period of 01. February and 01. May 2020 (Fig. 1 ). Median admission rate for exacerbated COPD was 47 ± 15 admissions per month (range 45–92 admissions). This rate was significantly lower when compared to the admission rate encountered during the same period in 2018/2019 (median 105 ± 8 admissions per month, range 78–131; 95% confidence interval (CI) −76.9 to −5.2, p = 0.030). Median admission rate ratio for 2020 to 2018/2019 was calculated with 0.58 ± 0.1 (range 0.34–0.85).

Fig. 1.

Hospitalized patients between 2018 and 2020.

A: Absolute numbers of hospitalized patients with exacerbated COPD (blue), myocardial infarction (red), and stroke (green) between 01. December

2017 and 01. May

2020. Dates of first confirmed COVID-19 cases in Europe and Germany are displayed. Curves were smoothed for display purposes.

A similar reduction in the admission rate of patients with myocardial infarction was seen during the study period when compared to 2018/2019 (admission rate ratio 0.85 ± 0.1, range 0.73–0.88; p = 0.029), whereas no significant reduction was detected at our institution for patients with stroke (admission rate ratio 0.86 ± 0.1, range 0.83–1.22; p = 0.388). The COPD admission rate ratio was significantly lower when compared to the admission rate ratio of myocardial infarction (95% CI -0.42 to −0.03, p = 0.027).

4. Discussion

We found a significant decrease of cases hospitalized for COPD at our institution since the first German case of COVID-19 was confirmed. Although the study is limited by its single-center design, the patient population encountered at our institution was previously shown to be highly representative for the German population including COPD case numbers [4]. Decreased hospitalization rates for patients with myocardial infarction after implementation of social containment measures for COVID-19 have been reported [5], and our data seem to suggest a similar association for COPD patients. Previous studies have speculated that containment measures may negatively impact established clinical care systems and avoidance of seeking medical attention to prevent hospital-acquired infections with COVID-19 [6]. We cannot comment on whether such mechanisms may have played a role in our cohort; however, such hypotheses need to be considered in future studies.

Surprisingly, we further encountered a larger decrease in COPD cases when compared to the decrease seen for patients with myocardial infarction. Whereas increased mortality was reported among COVID-19 patients in the presence of COPD, COPD seems overall underrepresented as comorbidity among patients with COVID-19 [1]. Contributing factors may include that medication used for COPD could also offer some protection against COVID-19, or underdiagnosis given the similarity of upper respiratory tract symptoms. Air pollution reduction and less exposure to environmental risk factors due to traffic restrictions, face masking or self-quarantine measures may have further contributed to decreased COPD patient numbers [7]; however, definitive factors remain to be elucidated. Thus, we will need prospective studies with more detailed data, including mortality statistics, patient interviews and air quality measurements.

Collectively, there appears to be a strong decrease in the COPD admission number since the first confirmed COVID-19 patient in Germany. Such a decrease might be even more profound than the decrease seen for patients with myocardial infarction.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.