How to measure smoking cessation; is there consensus? A Delphi study

Abstract

Background: Different criteria regarding outcome measures in tobacco smoking research are used which can lead to confusion and misunderstanding. Consensus in outcome criteria may enhance comparison of future studies. This study aims (1) to provide an overview of researchers’ preferences regarding outcome criteria to be considered in randomised controlled smoking cessation trials, and (2) to identify the extent to which researchers have consensus on the importance of these outcome criteria. Methods: A three-round online Delphi study was conducted among smoking cessation experts. In the first round the most important smoking cessation outcome measures were collected by means of open-ended questions. Experts were asked to name the outcome measure, its duration of abstinence or assessment method, and the ideal follow-up period. In the second and third rounds, experts were presented with a list of the outcome measures identified in the first round and were asked to rate the importance of the listed measures on a seven-point scale. Results: Experts reached consensus on several items, including six-month prolonged abstinence, and seven-day point prevalence. Preferred follow-ups included six and/or 12 months. The preferred biochemical validation methods were carbon monoxide (expired air), and cotinine (saliva); although validation is not always needed. Discussion: Findings suggest only partial compliance with the Russel standard and that more outcome measures may be important (including seven-day point-prevalence, number of cigarettes smoked, and cotinine when using biochemical validation). This study showed where there is and where there is no consensus and reflects the need to adjust/create a more comprehensive standard.