Influence of Matching for Exposure Time on Estimates of Attributable Mortality Caused by Nosocomial Bacteremia in Critically Ill Patients

2005 ◽  
Vol 26 (4) ◽  
pp. 352-356 ◽  
Author(s):  
Stijn Blot ◽  
Dirk De Bacquer ◽  
Eric Hoste ◽  
Pieter Depuydt ◽  
Koenraad Vandewoude ◽  
...  
Keyword(s):  
Cohort Study ◽  
Cohort Studies ◽  
Exposure Time ◽  
Attributable Mortality ◽  
Matched Cohort ◽  
Matched Cohort Study ◽  
Icu Stay ◽  
Nosocomial Bacteremia ◽  
Bacteremic Patient ◽  
And Control

AbstractObjective:To evaluate the influence of matching on exposure time on estimates of attributable mortality of nosocomial bacteremia as assessed by matched cohort studies.Design:Two retrospective, pairwise-matched (1:2) cohort studies.Setting:A 54-bed intensive care unit (ICU) in a university hospital.Patients:Patients with nosocomial Escherichia coli bacteremia (n = 68) and control-patients without nosocomial bacteremia (n = 136 for each matched cohort study).Intervention:In both matched cohort studies, the same set of bacteremic patients was matched with control-patients using the APACHE II system. In the first study, control-patients were required to have an ICU stay at least as long as the respective bacteremic patient prior to onset of bacteremia (matching on exposure time). In the second study, control-patients were required to have an ICU stay shorter than the stay prior to the development of bacteremia in the respective bacteremic patient (no matching on exposure time).Results:For bacteremic patients, the mean ICU stay before onset of the bacteremia was 9 days (median, 6 days). In the first matched cohort study, hospital mortality was not different between bacteremic patients and control-patients (44.1% vs 43.4%; P = .999). In the second study, mortality of bacteremic patients and control-patients was also not different (44.1% vs 47.8%; P = .657). Mortality rates between control groups were not different (43.4% vs 47.8%; P = .543).Conclusion:Matching or not matching on exposure time did not alter the estimate of attributable mortality for ICU patients with E. coli bacteremia.

scholarly journals Attributable mortality of vancomycin resistance in ampicillin-resistant Enterococcus faecium bacteremia in Denmark and the Netherlands: A matched cohort study

2021 ◽  
pp. 1-9
Author(s):  
Wouter C. Rottier ◽  
Mette Pinholt ◽  
Akke K. van der Bij ◽  
Magnus Arpi ◽  
Sybrandus N. Blank ◽  
...  
Keyword(s):  
Cohort Study ◽  
The Netherlands ◽  
Antibiotic Therapy ◽  
Enterococcus Faecium ◽  
Mortality Rates ◽  
Vancomycin Resistance ◽  
Attributable Mortality ◽  
Matched Cohort ◽  
Matched Cohort Study ◽  
The Impact

Abstract Objective: To study whether replacement of nosocomial ampicillin-resistant Enterococcus faecium (ARE) clones by vancomycin-resistant E. faecium (VRE), belonging to the same genetic lineages, increases mortality in patients with E. faecium bacteremia, and to evaluate whether any such increase is mediated by a delay in appropriate antibiotic therapy. Design: Retrospective, matched-cohort study. Setting: The study included 20 Dutch and Danish hospitals from 2009 to 2014. Patients: Within the study period, 63 patients with VRE bacteremia (36 Dutch and 27 Danish) were identified and subsequently matched to 234 patients with ARE bacteremia (130 Dutch and 104 Danish) for hospital, ward, length of hospital stay prior to bacteremia, and age. For all patients, 30-day mortality after bacteremia onset was assessed. Methods: The risk ratio (RR) reflecting the impact of vancomycin resistance on 30-day mortality was estimated using Cox regression with further analytic control for confounding factors. Results: The 30-day mortality rates were 27% and 38% for ARE in the Netherlands and Denmark, respectively, and the 30-day mortality rates were 33% and 48% for VRE in these respective countries. The adjusted RR for 30-day mortality for VRE was 1.54 (95% confidence interval, 1.06–2.25). Although appropriate antibiotic therapy was initiated later for VRE than for ARE bacteremia, further analysis did not reveal mediation of the increased mortality risk. Conclusions: Compared to ARE bacteremia, VRE bacteremia was associated with higher 30-day mortality. One explanation for this association would be increased virulence of VRE, although both phenotypes belong to the same well-characterized core genomic lineage. Alternatively, it may be the result of unmeasured confounding.

Acromioplasty rates in patients with shoulder disorders with and without acupuncture treatment: a retrospective propensity score–matched cohort study

2020 ◽  
Vol 38 (4) ◽  
pp. 255-263
Author(s):  
Gujin Yang ◽  
Boyoung Jung ◽  
Me-riong Kim ◽  
Wonil Koh ◽  
Namkwen Kim ◽  
...  
Keyword(s):  
Cohort Study ◽  
Propensity Score ◽  
Acupuncture Treatment ◽  
Acupuncture Group ◽  
Control Group ◽  
Matched Cohort ◽  
Control Groups ◽  
Matched Cohort Study ◽  
Shoulder Disorders ◽  
And Control

Objective: This retrospective propensity score–matched cohort study aimed to examine the frequency of acromioplasty among patients with shoulder disorders receiving and not receiving acupuncture, based on Korea National Health Insurance Service-National Sample Cohort (NHIS-NSC) data. Methods: We included cases of high-frequency shoulder disorders—adhesive capsulitis, rotator cuff syndrome, shoulder impingement syndrome, and sprain and strain of the shoulder joint—stratified from the Korea NHIS-NSC database between 2002 and 2013; cases were classified into two groups based on a history of acupuncture treatment performed at least twice within 6 weeks (acupuncture group: n = 111,561; control group: n = 71,340). We examined propensity scores and hazard ratios (HRs) for the frequency of acromioplasty, within 2 years of the first treatment or first examination in the acupuncture and control groups, respectively; cumulative survival rates were estimated using Kaplan–Meier survival analysis. Results: Following propensity score matching, no differences were observed between the acupuncture and control groups for variables including sex, age, income and the Charlson comorbidity index. In addition, the incidence rates of acromioplasty within 2 years were lower in the acupuncture group than in the control group (HR 0.264; 95% confidence interval 0.224–0.311). Based on differences in sensitivity analyses for the numbers of acupuncture sessions and treatment duration, the frequency of acromioplasty within 2 years was lower in the acupuncture group than in the control group. Conclusion: This study found that the frequency of acromioplasty was reduced in patients with shoulder disorders who had been treated with acupuncture. Although the findings need to be verified by prospective randomized clinical trials, these results imply that acupuncture may be effective at reducing the incidence rate of shoulder surgery.

scholarly journals Attributable mortality of antibiotic resistance in gram-negative infections in the Netherlands: a parallel matched cohort study

2020 ◽  
Author(s):  
Wouter C. Rottier ◽  
J.W. Timotëus Deelen ◽  
Giorgia Caruana ◽  
Anton G.M. Buiting ◽  
J. Wendelien Dorigo-Zetsma ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Cohort Study ◽  
The Netherlands ◽  
Attributable Mortality ◽  
Matched Cohort ◽  
Gram Negative ◽  
Matched Cohort Study

scholarly journals Attributable mortality of vancomycin resistance in ampicillin-resistant Enterococcus faecium bacteremia in Denmark and the Netherlands: a matched cohort study

2020 ◽  
Author(s):  
Wouter Carel Rottier ◽  
Mette Pinholt ◽  
Akke K. van der Bij ◽  
Magnus Arpi ◽  
Sybrandus N. Blank ◽  
...  
Keyword(s):  
Cohort Study ◽  
The Netherlands ◽  
Enterococcus Faecium ◽  
Length Of Hospital Stay ◽  
Vancomycin Resistance ◽  
Attributable Mortality ◽  
Genetic Lineage ◽  
Matched Cohort ◽  
Matched Cohort Study ◽  
Appropriate Therapy

Background: In many European hospitals, ampicillin-resistant Enterococcus faecium (ARE) is endemic, while outbreaks of vancomycin-resistant E. faecium (VRE), belonging to the same genetic lineage, are increasingly reported. We studied the attributable mortality due to vancomycin resistance in patients with E. faecium bacteremia and evaluated whether this is mediated by a delay in appropriate antibiotic therapy. Methods: In a retrospective matched cohort study, patients with VRE bacteremia occurring between 2009 and 2014 in 20 Dutch and Danish hospitals were matched to patients with ARE bacteremia, on hospital, ward, length of hospital stay prior to bacteremia, and age. The risk ratio (RR) for 30-day mortality contrasting VRE with ARE was estimated with further analytic control for confounding factors. Results: In all, 63 VRE and 234 ARE episodes were matched (36 and 130 for the Netherlands and 27 and 104 for Denmark). Crude 30-day mortality was 27% and 38% for ARE in the Netherlands and Denmark, respectively, and 33% and 48% for VRE in the respective countries. The adjusted RR for 30-day mortality for VRE was 1.54 (95% confidence interval (CI) 1.06-2.25). Although appropriate therapy was initiated later for VRE than for ARE bacteremia, this did not appear to mediate the increased mortality risk. Conclusions: Compared to ARE bacteremia, VRE bacteremia was associated with higher 30-day mortality. One explanation for this association would be increased virulence of VRE, although both phenotypes belong to the same well-characterized core genomic lineage. Alternatively, it may be the result of unmeasured confounding.

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