Impact of the "Zero Resistance" program on acquisition of multidrug-resistant bacteria in patients admitted to Intensive Care Units in Spain. A prospective, intervention, multimodal, multicenter study.

Objective: To assess the impact of a multimodal interventional project ("Zero Resistance") on the acquisition of multidrug-resistant bacteria (MDR-B) during the patient's ICU stay.

Design: Prospective, open-label, interventional, multicenter study.

Setting: 103 ICUs.

Study of risk factors for healthcare-associated infections in acute cardiac patients using categorical principal component analysis (CATPCA).

Using categorical principal component analysis, we aimed to determine the relationship between health care-associated infections (HAIs) and diagnostic categories (DCs) in patients with acute heart disease using data collected in the Spanish prospective ENVIN-HELICS intensive care registry over a 10-year period (2005-2015). A total of 69,876 admissions were included, of which 5597 developed HAIs. Two 2-component CATPCA models were developed.

Usefulness of therapeutic drug monitoring of piperacillin and meropenem in routine clinical practice: a prospective cohort study in critically ill patients.

Background: Beta-lactam anti-infective levels after standard dosing have been shown to be subtherapeutic when renal clearance is augmented.

Objective: To determine if piperacillin and meropenem are found to be in their therapeutic range in infected critically ill patients when administered by continuous intravenous infusion (CII) assisted by a therapeutic drug monitoring (TDM) report issued by the pharmacy service.

Methods: This prospective non-controlled intervention study evaluated septic patients in an intensive care unit.

Changes of resistance rates in Pseudomonas aeruginosa strains are unrelated to antimicrobial consumption in ICU populations with invasive device-related infection.

Objective: To evaluate the relationship between antipseudomonal antibiotic consumption and each individual drug resistance rate in Pseudomonas aeruginosa strains causing ICU acquired invasive device-related infections (IDRI).

Design: A post hoc analysis was made of the data collected prospectively from the ENVIN-HELICS registry.

Setting: Intensive Care Units participating in the ENVIN-UCI registry between the years 2007 and 2016 (3-month registry each year).

Analyzing the impact of duration of ventilation, hospitalization, and ventilation episodes on the risk of pneumonia.

Objective: To study the impact of duration of mechanical ventilation, hospitalization and multiple ventilation episodes on the development of pneumonia while accounting for extubation as a competing event.

Design: A multicenter data base from a Spanish surveillance network was used to conduct a retrospective analysis of prospectively collected intensive care patients followed from admission to discharge.

Setting: Spanish intensive care units (ICUs).

Improving nested case-control studies to conduct a full competing-risks analysis for nosocomial infections.

Objective: Competing risks are a necessary consideration when analyzing risk factors for nosocomial infections (NIs). In this article, we identify additional information that a competing risks analysis provides in a hospital setting. Furthermore, we improve on established methods for nested case-control designs to acquire this information.

Invasive device-associated infections caused by Pseudomonas aeruginosa in critically ill patients: evolution over 10 years.

Invasive device-associated infections caused by Pseudomonas aeruginosa over 10 years (2007-2016) were assessed based on data from the ENVIN-HELICS registry (200 Spanish intensive care units). P. aeruginosa was the leading pathogen except in the last two years in which there was a slight decrease, with Escherichia coli as the leading aetiology.

Methodological challenges in using point-prevalence versus cohort data in risk factor analyses of nosocomial infections.

Purpose: To explore the impact of length-biased sampling on the evaluation of risk factors of nosocomial infections (NIs) in point-prevalence studies.

Methods: We used cohort data with full information including the exact date of the NI and mimicked an artificial 1-day prevalence study by picking a sample from this cohort study. Based on the cohort data, we studied the underlying multistate model which accounts for NI as an intermediate and discharge/death as competing events.

Is a project needed to prevent urinary tract infection in patients admitted to spanish ICUs?

Objective: To analyze epidemiological data of catheter-associated urinary tract infection (CAUTI) in critically ill patients admitted to Spanish ICUs in order to assess the need of implementing a nationwide intervention program to reduce these infections.

Design: Non-intervention retrospective annual period prevalence analysis.

Setting: Participating ICUs in the ENVIN-UCI multicenter registry between the years 2007-2016.

Prevention of Ventilator-Associated Pneumonia: The Multimodal Approach of the Spanish ICU "Pneumonia Zero" Program.

Objectives: The "Pneumonia Zero" project is a nationwide multimodal intervention based on the simultaneous implementation of a comprehensive evidence-based bundle measures to prevent ventilator-associated pneumonia in critically ill patients admitted to the ICU.

Design: Prospective, interventional, and multicenter study.

Setting: A total of 181 ICUs throughout Spain.

Landmark prediction of nosocomial infection risk to disentangle short- and long-stay patients.

Length of stay is one of the key determinants for the risk of nosocomial infections. The distribution of this at-risk time is heavily skewed and depends on discharge or death. This study applied landmark competing risk prediction models to account for a large proportion of short-stay patients and a small proportion of long-stay patients.

A case-cohort approach for multi-state models in hospital epidemiology.

Analysing the determinants and consequences of hospital-acquired infections involves the evaluation of large cohorts. Infected patients in the cohort are often rare for specific pathogens, because most of the patients admitted to the hospital are discharged or die without such an infection. Death and discharge are competing events to acquiring an infection, because these individuals are no longer at risk of getting a hospital-acquired infection.

Risk factors for methicillin-resistant Staphylococcus aureus colonisation or infection in intensive care units and their reliability for predicting MRSA on ICU admission.

Predicting methicillin-resistant Staphylococcus aureus (MRSA) in intensive care units (ICUs) avoids inappropriate antimicrobial empirical treatment and enhances infection control. We describe risk factors for colonisation/infection related to MRSA (MRSA-C/I) in critically ill patients once in the ICU and on ICU admission, and search for an easy-to-use predictive model for MRSA colonisation/infection on ICU admission. This multicentre cohort study included 69,894 patients admitted consecutively (stay>24h) in April-June in the five-year period 2006-2010 from 147 Spanish ICUs participating in the National Surveillance Study of Nosocomial Infections in ICUs (ENVIN-HELICS).

Multiple time scales in modeling the incidence of infections acquired in intensive care units.

Background: When patients are admitted to an intensive care unit (ICU) their risk of getting an infection will be highly depend on the length of stay at-risk in the ICU. In addition, risk of infection is likely to vary over calendar time as a result of fluctuations in the prevalence of the pathogen on the ward. Hence risk of infection is expected to depend on two time scales (time in ICU and calendar time) as well as competing events (discharge or death) and their spatial location.

A full competing risk analysis of hospital-acquired infections can easily be performed by a case-cohort approach.

Objectives: We provide a case-cohort approach and show that a full competing risk analysis is feasible even in a reduced data set. Competing events for hospital-acquired infections are death or discharge from the hospital because they preclude the observation of such infections.

Study Design And Setting: Using surveillance data of 6,568 patient admissions (full cohort) from two Spanish intensive care units, we propose a case-cohort approach which uses only data from a random sample of the full cohort and all infected patients (the cases).

Trends in nosocomial infections and multidrug-resistant microorganisms in Spanish pediatric intensive care units.

Introduction: Nosocomial infections (NI) are a major healthcare problem. National surveillance systems enable data to be compared and to implement new measures to improve our practice.

Methods: A multicentre, prospective, descriptive and observational study was conducted using the data from surveillance system for nosocomial infections created in 2007 for Spanish pediatric intensive care units.

Analysis of Clinical Cohort Data Using Nested Case-control and Case-cohort Sampling Designs. A Powerful and Economical Tool.

Background: Sampling from a large cohort in order to derive a subsample that would be sufficient for statistical analysis is a frequently used method for handling large data sets in epidemiological studies with limited resources for exposure measurement. For clinical studies however, when interest is in the influence of a potential risk factor, cohort studies are often the first choice with all individuals entering the analysis.

Objectives: Our aim is to close the gap between epidemiological and clinical studies with respect to design and power considerations.

Multilevel competing risk models to evaluate the risk of nosocomial infection.

Introduction: Risk factor analyses for nosocomial infections (NIs) are complex. First, due to competing events for NI, the association between risk factors of NI as measured using hazard rates may not coincide with the association using cumulative probability (risk). Second, patients from the same intensive care unit (ICU) who share the same environmental exposure are likely to be more similar with regard to risk factors predisposing to a NI than patients from different ICUs.

[Respiratory infections caused by Aspergillus spp. in critically ill patients admitted to the intensive care units].

Unlabelled: The presence of respiratory fungal infection in the critically ill patient is associated with high morbidity and mortality.

Objectives: To assess the incidence of respiratory infection caused by Aspergillus spp. independently of the origin of infection in patients admitted to Spanish ICUs, as well as to describe the rates, characteristics, outcomes and prognostic factors in patients with this type of infection.

Interventions to control nosocomial infections: study designs and statistical issues.

There is a wide range of potential study designs for intervention studies to decrease nosocomial infections in hospitals. The analysis is complex due to competing events, clustering, multiple timescales and time-dependent period and intervention variables. This review considers the popular pre-post quasi-experimental design and compares it with randomized designs.

Nested case-control studies in cohorts with competing events.

In nested case-control studies, incidence density sampling is the time-dependent matching procedure to approximate hazard ratios. The cumulative incidence function can also be estimated if information from the full cohort is used. In the presence of competing events, however, the cumulative incidence function depends on the hazard of the disease of interest and on the competing events hazard.