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INTRODUCTION

Chapter Objectives

When you have completed this chapter, you will be able to understand:

  • What is an interventional study and its subtypes

  • What a randomized controlled trial is

  • The need for randomized controlled trials

  • How to plan and carry out a randomized controlled trial

  • The special characteristics of a randomized controlled trial

  • What the different types of randomized controlled trials are

  • The advantages and limitations of a randomized controlled trial as compared with other clinical research

  • Beyond clinical trials, the approach to secondary research such as systematic review and meta-analysis

In contrast to observational studies, in interventional studies the investigator tries to find a relation between an intervention and the outcome by exposing the participants to some kind of intervention, which can be a new drug, a surgical procedure, or a device, in order to evaluate it (Box 4-1). These studies can be done in basic sciences, in the community, or in clinical settings. A randomized controlled trial (RCT) is a type of clinical trial in which participants are allocated at random to receive one of several clinical interventions. Although the term intervention usually refers to treatment, it can include any clinical maneuver offered to participants that may have an effect on their health status, such as preventive strategies, screening programs, diagnostic tests, interventional procedures, or educational and learning models.1 The essence of an RCT is the process of randomization, through which each participant has an equal chance of being put either in the interventional or the control arm of the study. This prevents selection bias and increases the statistical power of the study.

BOX 4-1 What Are Interventional Studies?

Interventional studies try to find a relation between an intervention and the outcome by exposing participants to some kind of intervention in order to evaluate it. Although the term intervention usually refers to treatment, it can include any clinical maneuver offered to participants that may have an effect on their health status, such as preventive strategies, screening programs, diagnostic tests, interventional procedures, or educational and learning models.1

DIFFERENT TYPES OF INTERVENTIONAL STUDIES

Interventional studies can be done under various settings: in basic sciences, in the community, or in a clinical setup (Table 4-1).

TABLE 4-1Different Types of Interventional Studies

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