Original Articles
Prevalence and Risk Factors for Nosocomial Lower Respiratory Tract Infections in German Hospitals

https://doi.org/10.1016/S0895-4356(98)00012-2Get rights and content

Abstract

The prevalence and risk factors for nosocomial lower respiratory tract infections (LRTI) in Germany were determined as part of a national survey on nosocomial infections. The study included 14,966 patients in 72 representatively selected hospitals with departments of general medicine, surgery, obstetrics, gynecology, and intensive care units (ICU). Surveillance was carried out by four previously validated medical doctors who strictly applied the CDC-criteria for diagnosis of nosocomial infections. The overall prevalence of hospital-acquired LRTI was 0.72% with the highest rate in hospitals with more than 600 beds (1.08%) and among the patients on intensive care units (9.00%). Ventilator-associated pneumonia rates were highest in patients on ICUs (13.27). Polytrauma, impaired consciousness, chronic airway disease, prior surgery, and cardiovascular disease were significantly related to the occurrence of nosocomial LRTI. P. aeruginosa was the predominant organism causing nosocomial LRTI. Nosocomial LRTI remain a problem mainly on ICUs. Patients at risk should be monitored with extra care.

Introduction

Susceptibility to nosocomial infections (NI) has increased over the last few decades. Today patients are more likely to have a chronic underlying disease. Age, mechanical ventilation, aspiration, depressed consciousness, and impaired immunity are among the important risk factors for developing nosocomial pneumonia 1, 2, 3. Pneumonia ranks as the second or third most common type of NI behind urinary tract and wound infections 4, 5, 6. On intensive care units and especially in ventilated patients, it is the most common hospital-acquired infection [7] and is associated with a higher mortality rate in comparison to patients without nosocomial pneumonia depending on the patient’s risk profile and the virulence of the pathogen [8]. It may extend hospital treatment for up to 10 days and increases the cost of hospitalization 9, 10. Many efforts have been made to reduce patient morbidity, mortality, and hospital costs such as selective decontamination of the digestive tract (SDD), substitution of antacids and H2-blockers with cytoprotective agents, and placing the ventilated patient in a semirecumbent position 11, 12, 13, 14. Many risk factors for morbidity and mortality have been evaluated [15].

A nationwide survey on the prevalence of hospital-acquired infections (NIDEP study) was carried out in 1994. This article presents a part of the results, the prevalence of nosocomial LRTI, describes patient risk factors, and compares these rates with community-acquired LRTI.

Section snippets

Study Design and Criteria for Nosocomial and Community-Acquired Infections

Part one of the NIDEP study (Nosocomial infections in Germany—Surveillance and Prevention) was designed as a prevalence study. The surveillance was carried out by external investigators, not by hospital personnel. Investigators decided about the presence of NI according to the 1988 CDC-criteria [16]. All of the following types of infections were regarded as LRTI: (1) pneumonia, (2) bronchitis, tracheobronchitis, bronchiolitis, or tracheitis without any signs of pneumonia, and (3) other

All Nosocomial LRTI

The overall prevalence of nosocomial LRTI was 0.72%. They represent 20.7% of all patients with NI (n = 518) [22]. The highest rate was found on intensive care units (9.00%), while it was uncommon in surgical and obstetrical/gynecological departments (Table 2). Pneumonia was the most common type of LRTI (0.54%). Hospital-acquired bronchitis was predominant in intensive care patients (2.74%) with an overall rate of 0.15%. The difference between the four departments was significant for the LRTI (P

Discussion

The most extensive study to date on the prevalence of NI in Germany (NIDEP study) revealed an overall LRTI rate of 0.72%, the majority being pneumonia (74.8%). The design of a prevalence survey has been chosen because data are much easier to obtain and might therefore be more useful for comparison between hospitals or departments where routine surveillance of NI is carried out. Other countries have reported higher prevalence rates (Table 6). In Norway [23], Spain [24], Hong Kong [25], Italy [26]

Acknowledgements

This study was supported by the German Ministry of Health.

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