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A Systematic Review of Quasi-Experimental Study Designs in the Fields of Infection Control and Antibiotic Resistance

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A Systematic Review of Quasi-Experimental Study Designs in the Fields of Infection Control and Antibiotic Resistance INVITED ARTICLE ANTIMICROBIAL RESISTANCE George M. Eliopoulos, Section Editor A Systematic Review of Quasi-Experimental Study Designs in the Fields of Infection Control and Antibiotic Resistance Anthony D. Harris,1,2 Ebbing Lautenbach,3,4 and Eli Perencevich1,2 1 2 Division of Health Care Outcomes Research, Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, and Veterans Downloaded from https://academic.oup.com/cid/article/41/1/77/325424 by guest on 24 September 2021 Affairs Maryland Health Care System, Baltimore, Maryland; and 3Division of Infectious Diseases, Department of Medicine, and 4Department of Biostatistics and Epidemiology, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania We performed a systematic review of articles published during a 2-year period in 4 journals in the field of infectious diseases to determine the extent to which the quasi-experimental study design is used to evaluate infection control and antibiotic resistance. We evaluated studies on the basis of the following criteria: type of quasi-experimental study design used, justification of the use of the design, use of correct nomenclature to describe the design, and recognition of potential limitations of the design. A total of 73 articles featured a quasi-experimental study design. Twelve (16%) were associated with a quasi-exper- imental design involving a control group. Three (4%) provided justification for the use of the quasi-experimental study design. Sixteen (22%) used correct nomenclature to describe the study. Seventeen (23%) mentioned at least 1 of the potential limitations of the use of a quasi-experimental study design. The quasi-experimental study is used frequently in studies of infection control and antibiotic resistance. Efforts to improve the conduct and presentation of quasi-experimental studies are urgently needed to more rigorously evaluate interventions. In the study of infectious diseases and, in particular, the study quasi-experimental design when seeking to establish stronger of infection control and antibiotic resistance, the quasi-exper- causal associations between interventions and outcomes. These imental study design, sometimes called the “pre-post interven- improvements could lead to more valid conclusions about the tion” or “before-after intervention” study design, is often used effectiveness of interventions in the areas of infection control to evaluate the effectiveness of specific interventions. In the and antibiotic resistance. social sciences, studies of the methodological principles for op- The prevalence of the use of the quasi-experimental study timizing quasi-experimental studies and the relative hierarchy design in the literature on infection control and antibiotic re- of quasi-experimental study designs have been published during sistance is not known. In addition, it is unknown how well the past several decades [1, 2]. However, little has been written studies describe the type of quasi-experimental design used or about the optimal use of the quasi-experimental design in the its potential limitations. Such data are important for better field of infectious diseases. In a recent article, we reviewed the evaluating the results of such studies and the interventions they existing literature featuring quasi-experimental study designs seek to explore. and proposed a relative hierarchy of the specific quasi-exper- In this article, we report results of a systematic review of imental study designs and epidemiological design methods to articles published during a 2-year period in 4 journals in the improve the internal validity of quasi-experimental studies in field of infectious diseases and determined the extent to which the field of infectious diseases [3]. The aim of the previous quasi-experimental study designs are used in reports about in- article was to identify methods for optimizing the use of the fection control and antibiotic resistance. In addition, we sought to analyze variations in the use of quasi-experimental study Received 19 January 2005; accepted 23 March 2005; electronically published 20 May 2005. designs and in the description and acknowledgment of the Reprints or correspondence: Dr. Anthony Harris, Div. of Health Care Outcomes Research, Dept. of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, potential advantages and disadvantages of such designs. By eval- 100 Greene St., Lower Level, Baltimore, MD 21201 ([email protected]). uating the use and knowledge of quasi experiments, we aimed Clinical Infectious Diseases 2005;41:77–82 to highlight potential limitations in the existing literature and ᮊ 2005 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2005/4101-0013$15.00 areas for potential improvement. ANTIMICROBIAL RESISTANCE • CID 2005:41 (1 July) • 77 Downloaded from https://academic.oup.com/cid/article/41/1/77/325424 by guest on 24 September 2021 Figure 1. Hierarchy of quasi-experimental study designs. As one moves down between and within each category, the quality of the study designs increase (e.g., in category A, study design 5 is of higher quality than study design 4). Time moves from left to right. O, observational measurement; X, intervention under study. METHODS used, justification of the use of the design, use of correct no- menclature to describe the design, and recognition of potential We systematically reviewed articles published during a 2-year limitations of the design. period (1 January 2002 through 31 December 2003) in 4 major Type of quasi-experimental study design used (criterion 1). journals in the field of infectious diseases (Infection Control and We first reviewed the previously published hierarchy of quasi- Hospital Epidemiology, American Journal of Infection Control, Clinical Infectious Diseases, and Emerging Infectious Diseases) to experimental designs in the field of infectious diseases [3]. We determine the number of quasi-experimental studies. Two of slightly modified a priori the quasi-experimental study designs the 3 authors reviewed the titles and abstracts of every article listed in the hierarchy by adding a category B study design that published in the 2-year period to determine whether the article uses control groups but no pretests (study design B0 in figure featured a quasi-experimental study design. Only quasi-exper- 1). The result, summarized in figure 1, was then used to classify imental studies that focused on infection control or antibiotic the studies according to criterion 1. In general, a quasi-experi- resistance were included in the subsequent review. Two of the mental design that uses a control group (category B) is preferable 3 then reviewed the articles and classified them on the basis of to a design that does not use a control group (category A). In the following 4 criteria: type of quasi-experimental study design addition, the quality of the study designs increases as one moves 78 • CID 2005:41 (1 July) • ANTIMICROBIAL RESISTANCE down within each category (e.g., in category A, the quality of Criterion 2 involved determination of whether the authors study design 5 is higher than that for study design 4). justified their choice of the quasi-experimental study design. Justification of the use of the quasi-experimental study de- Authors of 3 articles (4%) justified their use of the quasi- sign (criterion 2). We reviewed the articles to see whether the experimental study design [15, 17, 25]. authors explained or justified why they chose the quasi-exper- Criterion 3 involved determination of whether the authors imental study design instead of other study designs. We rated used the correct nomenclature to describe the quasi-experi- satisfaction of this criterion as “yes” or “no.” If the authors mental study design. Authors of 16 articles (22%) correctly made any mention as to why they chose the quasi-experimental described the study design [11, 13, 17, 25, 33, 34, 40, 41, 43, design (e.g., because a randomized, controlled trial would be 48, 52, 54, 55, 63, 68, 76]. Common, nonstandard, and inac- unethical or infeasible), the design was rated as “yes” for this curate nomenclature used to describe apparent quasi experi- criterion. ments included names such as “descriptive study design” and Use of correct nomenclature to describe the quasi-experi- “controlled intervention trial.” mental study design (criterion 3). We noted whether authors Criterion 4 involved determination of whether the authors Downloaded from https://academic.oup.com/cid/article/41/1/77/325424 by guest on 24 September 2021 correctly identified their study as a quasi-experimental study. recognized some of the limitations of the quasi-experimental Articles that used the terms “quasi-experimental,” “before-after study design. Authors of 17 articles (23%) mentioned at least study,” and/or “pre-post study” were deemed to have used 1 of the potential limitations associated with quasi-experimental correct nomenclature. Satisfaction of this criterion was rated study designs [11, 13, 15, 17, 18, 25, 29, 34, 37, 38, 48, 50, 56, as “yes” or “no.” 57, 63, 68, 71]. Potential limitations that were mentioned in- Recognition of potential limitations of the quasi-experi- cluded the preferability of a randomized trial, the possibility mental study design (criterion 4). Because the quasi-exper- that temporal confounders were present, and the problems as- imental study design has recognized limitations, we sought to sociated with use of data
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