Original Article
Trends in hospitalizations for community-acquired pneumonia in Spain: 2004 to 2013

https://doi.org/10.1016/j.ejim.2016.12.010Get rights and content

Highlights

  • Hospitalizations for CAP have increased in Spain in recent years.

  • Streptococcus pneumoniae continue being the most frequent causative agent of CAP.

  • In-hospital mortality have decreased over time in patients with a diagnosis of CAP.

Abstract

Aim

To describe trends in the incidence and outcomes of community-acquired pneumonia (CAP) hospitalizations in Spain (2004–2013).

Methods

We used national hospital discharge data to select all hospital admissions for CAP as primary diagnosis. We analyzed incidence, Charlson comorbidity index (CCI), diagnostic and therapeutic procedures, pathogens, length of hospital stay (LOHS), in-hospital mortality (IHM) and readmission.

Results

We identified 959,465 admissions for CAP. Incidence rates of CAP increased significantly over time (from 142.4 in 2004 to 163.87 cases per 100,000 inhabitants in 2013). Time trend analyses showed significant increases in the number of comorbidities and the use of CAT of thorax, red cell transfusion, non-invasive mechanical ventilation and readmissions (all p values < 0.05). S. pneumoniae was the most frequent causative agent, but its isolation decreased over time. Overall median of LOHS was 7 days and it did not change significantly during the study period. Time trend analyses also showed significant decreases in mortality during admission for CAP. Factor associated with higher IHM included: older age, higher CCI, S. aureus isolated, use of red cell transfusion or mechanical ventilation and readmission.

Conclusions

The incidence and mortality of CAP have changed in Spain from 2004 to 2013. Although there was an increased incidence of hospitalization for this disease over time, we saw a significant reduction in IHM.

Introduction

Community-acquired pneumonia (CAP) is one of the most common infections requiring hospitalizations worldwide, resulting in a significant clinical and economic burden, especially in the elderly [1], [2]. Both incidence and mortality, as well as costs associated with this disease vary, not only with age, but also with gender and comorbidity [3], [4]. S. pneumonia is the leading causative agent in all age groups and is the major bacterial cause of adult CAP that requires hospitalization [5].

Although there is a high variability in published data of incidence of CAP, hospital admissions for pneumonia appears to be increasing [6], [7], [8], which may be due to their aging populations and a higher prevalence of concomitant diseases [9]. However, these trends are surprising in light of smoking cessation campaigns and increased uptake of influenza and pneumococcal vaccination among high risk groups [7]. In fact, in recent studies in U.S. it has been observed a substantial reduction in hospitalization for pneumonia after the introduction of 7-valent pneumococcal conjugate vaccine [10], [11]. However, recent data of the burden of CAP are lacking for most European countries.

Despite the significant impact of this disease, studies conducted in Spain on the epidemiology of CAP are scarce, with figures of incidence varying, and sometimes with many years since its realization [12], [13]. Administrative databases are attractive candidates for health services research, because the number of patient records is large and the acquisition cost is low [14]. Observational studies using these data can be used to understand disease patterns and burden of pneumonia [12], [13].

A better understanding of the burden of CAP could help in planning preventive strategies and improving clinical management [15]. In this study, we used national hospital discharge data to examine trends in incidence and outcomes of CAP in Spain from 2004 to 2013. In particular, we analyzed patient comorbidities, diagnostic and therapeutic procedures, pneumonia pathogens and in-hospital outcomes, length of hospital stay (LOHS), in-hospital mortality (IHM) and readmissions.

Section snippets

Methods

We performed a retrospective, observational study using the Spanish National Hospital Discharge Database (CMBD, Conjunto Mínimo Básico de Datos), which 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 [16]. 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 hospital stay.

Results

From 2004 to 2013, we identified a total of 959,465 admissions for CAP as primary diagnosis in patients aged ≥ 18 years in Spain. Table 1 shows the incidence according to sex and age in these patients. Incidence increased significantly, from 142.4 cases per 100,000 inhabitants in 2004 to 163.87 in 2013. In both sexes a significant increase was observed over time, from 208.24 to 227.59 in males and from 92.17 to 116.28 in females (Fig. 1). In both sexes, an increase in incidence with increasing

Discussion

In contrast to the declining rates of pneumonia-related hospitalization recently observed in the U. S [11], we found a significant increase in hospitalizations with CAP in Spain between 2004 and 2013. These results are consistent with a report from Denmark [7], which pointed that total pneumonia hospitalization increased by 63%, from 4.96 per 1000 population in 1997 to 8.09 in 2011. More recently Quan et al. [8], using data from the Infections in Oxfordshire Research Data, concluded that

Conflict of interest statement

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

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      Procedures studied were invasive and non-invasive mechanical ventilation, thoracocentesis, bronchial fibroscopy, computerized axial tomography of thorax, dialysis, and oxygen therapy prior to hospital admission (Supplementary Table 1). These procedures were selected because previous studies have found them associated with severity and in hospital mortality among patients hospitalized with CAP [19, 20]. The "oxygen therapy prior to hospital admission" ICD10 code is recorded in patients with any of the following conditions present before admission to the hospital, “Long term dependence on nocturnal oxygen therapy”, “Long term dependence on continuous supplemental oxygen” or “Long term dependence on supplemental oxygen when ambulating”.

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