A study aims to investigate the effectiveness of the topical application of tetracycline ointment in the prevention of surgical-site infection associated with resection of advanced oral cavity cancer. Fifty patients who underwent locoregional resection were assigned by chance to receive standard care alone or tetracycline-ointment in addition to standard care. The patients were then followed for 1 month and the number and severity of surgical-site infections were recorded for each group. Which of the following best describes the study design?

Question

A study aims to investigate the effectiveness of the topical application of tetracycline ointment in the prevention of surgical-site infection associated with resection of advanced oral cavity cancer.  Fifty patients who underwent locoregional resection were assigned by chance to receive standard care alone or tetracycline-ointment in addition to standard care.  The patients were then followed for 1 month and the number and severity of surgical-site infections were recorded for each group.  Which of the following best describes the study design?

Quizplus · Accepted Answer

Research studies are classified as observational studies (eg, cross-sectional, case control, cohort) or experimental studies (eg, randomized control trials, factorial, crossover), depending on how much control a researcher has over the independent variables (eg, risk factors/exposures, interventions) in a study. The main differences between these 2 types of study designs are as follows: In observational designs, the researcher observes the effect of naturally occurring risk factors/exposures on outcomes of interest. In experimental designs, the researcher randomly assigns interventions to potential participants to assess the effect of the controlled interventions. A randomized control trial is one of the simplest subtypes of experimental designs; it is an experiment in which participants are randomly allocated to ≥2 groups to assess the effect of specific interventions (eg, treatments). In this example, 50 patients who underwent surgical resection of advanced oral cavity cancer were assigned by chance into either a tetracycline-ointment treatment group or a standard-of-care control group. The effectiveness of the topical application of tetracycline ointment for prevention of surgical-site infection was then assessed by recording the incidence and severity of infections in each group. (Choice A) A case-control study is a type of observational study in which potential participants are initially identified as cases or controls according to outcome status (ie, developing the disease or condition of interest); the 2 groups are then assessed on their past exposure to specific risk factors. (Choice B) A crossover study is an experiment in which subjects are exposed to different treatments or exposures sequentially. In the above scenario, patients are exposed to a single treatment only. (Choices C and E) In prospective cohort studies, exposure status is determined in the present and patients are tracked over time for development of the outcome of interest; in retrospective cohort studies, exposure status is determined at a particular point in the past, and participants are tracked retrospectively, typically through their medical records. However, participants in cohort studies already have a definite exposure status; they are not randomly assigned to exposure groups as in the above example. Educational objective: A randomized control trial is an experiment in which participants are randomly allocated to ≥2 groups to assess the effect of specific interventions (eg, treatments).

A Study Aims to Investigate the Effectiveness of the Topical