Original Article
Impact of COPD on outcomes in hospitalized patients with community-acquired pneumonia: Analysis of the Spanish national hospital discharge database (2004–2013)

https://doi.org/10.1016/j.ejim.2017.06.008Get rights and content

Highlights

  • Hospital admissions for CAP increased over time in patients with and without COPD.

  • In-hospital mortality decreased over time in both groups of patients.

  • There were no differences in mortality by COPD status during admissions for CAP.

Abstract

Aim

To examine trends in incidence and outcomes of community-acquired pneumonia (CAP) hospitalizations among patients with or without COPD in Spain (2004–2013).

Methods

We used national hospital discharge data to select all hospital admissions for CAP. Incidence was calculated overall and according to the presence or absence of COPD.

Results

We identified 901,136 hospital admissions for CAP (32.25% with COPD). Incidence of hospitalizations of CAP increased significantly over time among patients with and without COPD, but it was higher among people with COPD for all years analyzed. S. pneumoniae decreased over time for both groups. Time trend analyses showed significant decreases in mortality during admission for CAP for patients with and without COPD. Factor independently associated with higher mortality in both groups included: male sex, older age, higher comorbidity, isolation of S. aureus or P. aeruginosa, use of mechanical ventilation, and readmission. The presence of COPD was associated with a lower in-hospital mortality (IHM) (OR: 0.58, 95%CI 0.57–0.59).

Conclusions

The incidence of hospitalizations for CAP increased over time in patients with and without COPD, being higher in the COPD population for all years analyzed. IHM decreased over time in both groups. There were no differences in mortality between COPD and non-COPD patients.

Introduction

Community-acquired pneumonia (CAP) is one of the most common infectious cause of hospitalization in developed countries. It has been consistently associated with high morbidity and mortality, being the ninth leading cause of death [1]. Complications of this disease include the development of empyema, sepsis, acute respiratory distress syndrome and respiratory failure [2], [3].

The risk factors for the development of CAP include advanced age and comorbid illnesses [4]. Chronic obstructive pulmonary disease (COPD) is a frequent associated condition in patients hospitalized with CAP. Previous studies have reported rates between 15% and 42%, depending on the population studied [5], [6], [7], [8], [9], [10], [11], [12]. Patients with COPD may have increased susceptibility to pneumonia for several reasons. They have structural disruptions in the lung parenchyma, and frequently receive antibiotic and oral or inhaled steroids treatment. Moreover, this condition is characterized by a chronic inflammation of the respiratory tract and it may be associated with an altered local and systemic immunity [1], [13]. For these reasons, the presentation of CAP in COPD patients may differ from that of patients without this condition [14].

The true impact of COPD in patients hospitalized with CAP is not yet clear [12]. Previous studies of the interaction between both disorders have yielded conflicting results. Some studies have shown that COPD is a risk factor for higher CAP severity [15], whereas others suggest that COPD is a protective factor against the development of complications of CAP [16], [17]. Moreover, the influence of COPD on the mortality of CAP patients remains controversial [18].

In Europe, the admissions due to CAP are increasing, with COPD being a commonly encountered comorbidity [19], [20]. However, to our knowledge, no previous studies have investigated national trends in the incidence, characteristics and outcomes of CAP in people with COPD in Spain.

The analysis of large population databases could provide a “real-world” perspective of the impact of COPD in patients with CAP. In this study, we used national hospital discharge data to examine trends in incidence and outcomes of CAP among patients with or without COPD in Spain from 2004 to 2013. In particular, we analyzed patient comorbidities, diagnostic and therapeutic procedures, pneumonia pathogens and in-hospital outcomes, such as readmission, in-hospital mortality (IHM) and length of hospital stay (LOHS).

Section snippets

Methods

We performed a retrospective, observational study using the Spanish National Hospital Discharge Database (CMBD, Conjunto Mínimo Básico de Datos). This database is managed by the Spanish Ministry of Health, Social Services and Equality and compiles all public and private hospital data, covering > 98% of hospital admissions [22]. The CMBD includes patient variables (sex, date of birth), admission and discharge dates, up to 14 discharge diagnoses, and up to 20 procedures performed during the

Results

During the study period, we identified 901,136 hospital admissions for CAP as primary diagnosis in patients aged ≥ 40 years. 33.25% of them also had a diagnosis of COPD. Fig. 1 shows the incidence of hospitalizations for CAP and its distribution according to sex among patients with and without COPD. In both cases, we found a significant increase in incidence over time from 1344 cases per 100,000 inhabitants in the period 2004–2005 to 1640 in the period 2012–2013 among COPD patients. In patients

Discussion

In this study, we found a significant increase in hospitalization rates for CAP in patients with and without COPD from 2004 to 2013. These results are in agreement with those registered by other authors [27], [28]. Among the possible explanations that may justify these findings are, more low-severity cases are presenting to hospital and being admitted and ageing population [28], [29], [30]. We also demonstrated that readmissions for CAP increased over time in patients with and without COPD and

Conflict of interest statement

The authors do not have any commercial or other association that might pose a conflict of interest.

Acknowledgements

This study was funded by the FIS (Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III) co-financed by the European Union through the Fondo Europeo de Desarrollo Regional (FEDER, “Una manera de hacer Europa”)—Health Research Fund, grants no. PI13/00118 and PI16/00564, and by the Grupo de Excelencia Investigadora URJC-Banco Santander No. 30VCPIGI03: Investigación traslacional en el proceso de salud—enfermedad (ITPSE).

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