The demographics of the samples of these studies were fairly similar to each other and appeared to be similar to the average characteristics of U.S. smokers (Hughes & Callas, 2010) except that most studies had few minorities. http://www.selleckchem.com/products/Bosutinib.html We report four methods that can be used to draw conclusions. The first is experimental replication across studies, that is, the proportion of studies in which the quit rate for the NRT user group was greater than that in the nonuser group. For this analysis, whenever possible, we recalculated the percent abstinent for NRT users and nonusers, and the unadjusted OR for NRT users versus nonusers, using ITT denominators (Table 2). AORs were taken directly from the reports. If OTC NRT is effective, then the OR for quit rates in OTC NRT users versus nonusers should be greater than 1.

0 (to avoid labeling minor increases important, we required > 1.1 for our analyses). In the unadjusted analyses, the OR was numerically greater than 1.1 in 7/11. Given the known selection biases, more weight should be placed on the adjusted analyses, even though their adjustments were incomplete. In the adjusted analyses, OTC NRT was numerically greater than 1.1 in 6/9 comparisons. If data from treatment studies are ignored for the reasons listed above, then the unadjusted OR is numerically greater than 1.1 in 4/8 of the unadjusted comparisons and in 4/6 of the adjusted comparisons. The second method is the fraction of studies that found statistically significant greater quitting among NRT users. About half (5/11) of the unadjusted comparisons show significantly greater quitting with NRT users and all (6/6) of the adjusted analyses did so.

Among non-treatment samples, corresponding fractions were 2/6 and 3/8. The third method is examination of the studies, which appear to have the greatest internal and external validity. As described above, the Shiffman et al. study is probably the most rigorous. It did not find NRT to be effective. Table 2. Outcomes of Retrospective Cohort Studies The fourth method is based on specificity, that is, instances in which OTC NRT users did not show increased rates, but users of other drugs or counseling assumed to be effective (bupropion and phone counseling) did show increased rates, that is, inclusion of other drugs or counseling as a ��positive control.�� This criterion is important to rule out the possibility that instances of failure to show efficacy of NRT are due to biased or insensitive methods. Bupropion was associated with success in 3/4 comparisons, but receipt of counseling was associated with success in 0/4 comparisons (Gilpin et al., 2006; Shiffman et al., 2008b; Carfilzomib Solberg et al., 2001). There was no study in which bupropion or counseling was found effective and NRT was not.