Potential Consequences for Recruitment, Power, and External Validity of Requirements for Additional Risk Factors for Eligibility in Randomized Controlled Trials in Secondary Prevention of Stroke

Abstract

The degree of patient selection introduced by use of additional vascular risk factors as eligibility criteria for trials can differ substantially between apparently similar sets of risk factors. Given that the potential for additional eligibility criteria to undermine generalizability and prolong recruitment outweighs any benefits in terms of statistical power, the exclusion of patients with no risk factors is difficult to justify.