The reach ratio--a new indicator for comparing quitline reach into smoking subgroups

There is growing concern about population disparities in tobacco-related morbidity and mortality. This paper introduces the reach ratio as a complementary measure to reach for monitoring whether quitline interventions are reaching high risk groups of smokers proportionate to their prevalence in the population.

Data on smokers were collected at intake by 7 Canadian provincial quitlines from 2007 to 2009 and grouped to identify 4 high risk subgroups: males, young adults, heavy smokers, and those with low education. Provincial data are from the Canadian Tobacco Use Monitoring Survey. Reach ratios (ReRas), defined as the proportion of quitline callers from a subgroup divided by the proportion of the smoking population in the subgroup, and 95% confidence intervals were calculated for the subgroups. A ReRa of 1.0 indicates proportionate representation.

ReRas for male smokers and young adults are consistently less than 1.0 across all provinces, indicating that a lower proportion of these high-risk smokers were receiving evidence-based smoking cessation treatment from quitlines. Those with high levels of tobacco addiction and less than high school education have ReRas greater than 1.0, indicating that a greater proportion of these smokers were receiving cessation treatments.

ReRas complement other measures of reach and provide a standardized estimate of the extent to which subgroups of interest are benefiting from available cessation interventions. This information can help quitline operators, funders, and policymakers determine the need for promotional strategies targeted to high risk subgroups, and allocate resources to meet program and policy objectives.