The controlled single subject trial

Abstract

Randomized controlled trials in single subjects ('N of 1 RCT') are double-blind, multi crossover trials in which the effects of two or more treatments are compared within one individual. The aim is to provide a controlled assessment of the efficacy of a new drug in a specific patient. Suitable diseases for single subject trials are particularly those which significantly impair the quality of life and in which there are uncertain treatment effects. Appropriate drugs should have a prompt action, a minimum of carry-over effect, and no side-effects. The trial design is determined by the length, number, and order of successive treatment periods, the outcome measures, and the statistical requirements. Each of these elements may be altered and tailored to the clinical entity and drug(s) applied, thus, providing a large potential for design options.