Health-related quality of life (HRQoL) is a measure of the day-to-day functioning and well-being of a person that is used to assess the effect of illness or injury over time. HRQoL measurements are important to public policy, because they reflect the short- and longer-term impact of healthrelated interventions, such as reducing or quitting smoking cigarettes.
HRQoL is best quantified using self-assessed personal questionnaires, a well-established procedure in population health surveys and clinical research. However, sometimes a statistical problem called a ‘ceiling effect’ can prevent questionnaires from detecting health related improvements in respondents who score at the top of the ‘well’ range to start with. The general
health survey SF-36, for example, is widely used in clinical trials of smoking populations but is known to have ceiling effects in surveys of healthy smokers. This, alongside an absence of questions specific to smoking-related health within surveys such as SF-36, makes it more difficult to adequately differentiate between ‘otherwise healthy’ current, former and never
To accurately assess the impact on HRQoL of next generation tobacco and nicotine products, within the scope of public health, improvements are required to current methods of evaluation. Improvements would allow the questionnaires to reduce the ceiling effect, to better discriminate between types of smokers and to detect the effects caused by different products.
In collaboration with the world-leading expert on HRQoL, Professor John E. Ware Jr., founder and Chief Science Officer at John Ware Research Group Inc. and Professor at the University of Massachusetts Medical School, researchers at British American Tobacco have evaluated the Tobacco Quality of Life Impact Tool (TQoLIT). The TQoLIT is an improved HRQoL questionnaire that is designed to be more sensitive than general health surveys such as SF-36 at detecting HRQoL changes in current and former smokers.
TQoLIT is tailored to smoking-related research by including additional questions that focus on HRQoL attributed specifically to smoking. For example, one question asks how often smoking limited physical activities over the past month. Questions in TQoLIT also extend the range of measurement of perfect functional health. For instance, instead of just measuring the absence of limitations in physical activities, it also measures how easy it is to perform those physical activities.
The researchers used TQoLIT to assess otherwise healthy adult current and former smokers in a 6-month study that explored the effect of smokers switching to reduced toxicant prototype cigarettes. The results are published in Nicotine & Tobacco Research .
The results show that TQoLIT is indeed much better than SF-36 at discriminating between former and current smokers because only 35% of respondents could not improve due to a ceiling effect in TQoLIT’s measure of physical function, compared with 59% in SF-36 survey.
‘Our results show that increasing the measurement range to include higher levels of HRQoL, and including impact questions with specific attribution to smoking, are essential in evaluating changes in HRQoL among otherwise healthy smokers,’ says Ware.
The researchers also found that new smoking specific-impact measures in TQoLIT enabled detection of significant HRQoL changes in smokers who switched to a reduced toxicant prototype cigarette.