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New Tobacco-specific Quality of Life Impact Tool (TQOLIT) showed measurement advantages in study of otherwise healthy smokers

WORCESTER, MA, April 27, 2015 – A new quality of life instrument, the Tobacco Quality of Life Impact Tool (TQOLIT™), developed by the John Ware Research Group, was proven to be useful in a 6-month clinical trial of the effects of switching smokers to a reduced toxicant prototype cigarette. Like many smoking studies, this trial focused on young and otherwise healthy adult current and former smokers for whom reliable measurement throughout the range of functional health and well-being is critical.  The results were recently published in Nicotine & Tobacco Research.

Measuring the health-related quality of life (HRQOL) of young and middle-aged smokers is challenging because many of the impacts of smoking are not apparent for decades. In addition, prior to QDIS there was no brief HRQOL scale that measured the impact of smoking on physical, emotional and social aspects of life. TQOLIT integrates several JWRG advances in patient-reported outcomes (PRO) measurement to address these challenges.

First, TQOLIT includes a short 7-item scale that measures the impact of smoking on quality of life. The TQOLIT smoking impact measure is a smoking-specific version of JWRG’s QOL Disease Impact Scale (QDIS®), which is a comprehensive disease-specific PRO measure that is standardized across 35 chronic conditions. For TQOLIT, QDIS was adapted to ask about limitations in HRQOL specifically attributed to smoking. For example, one question asks how often smoking limited everyday activities over the past four weeks, while another question asks how often smoking led to worrying about health now or in the future. Trial results showed that the QDIS smoking impact scale performed better than the SF-36 Health Survey in tests of validity in discriminating between current and former ‘otherwise healthy’ smokers. In addition, the QDIS smoking impact scale significantly differentiated between smokers who did and did not switch to a reduced toxicant prototype cigarette.

TQOLIT also includes questions from JWRG’s generic quality of life scales (QGEN®), which extend the range of PRO measurement beyond the mere absence of limitations in everyday functional activities to also measure how easy it is to perform those activities. One result is that QGEN more reliably measures the top of the ‘well’ range of functional health. This reduces a critical problem called a ‘ceiling effect’ that can prevent detection of improvements among participants who would have already earned the highest possible score at the start of a trial.  For example, 59% of trial participants could not improve when the SF-36 was used to measure physical functioning due to a ceiling effect, compared to only 35% of participants who could not improve using the TQOLIT physical functioning measure.

TQOLIT also incorporates norm-based scoring for both disease-specific and generic PROs, which is beneficial in interpreting trial results. Scores on the TQOLIT smoking impact measure are interpreted in relation to scores for a representative sample of ever (current and former) smokers in the U.S. general population, while QGEN measures included in TQOLIT are interpreted in relation to scores for a representative sample of the total U.S. general population.

Additional measures in TQOLIT include an 8-item scale measuring the frequency of symptoms related to smoking and a brief measure of confidence in current and future health, which qualitative research has shown to be a key concern of smokers. John Ware and colleagues from JWRG collaborated with researchers from British American Tobacco, Group Research & Development, to evaluate the psychometric properties of TQOLIT in the Nicotine & Tobacco Research study.

Monday, April 27, 2015 by JWRG