The results of this meta-analysis supported the notion that tailored interventions are an effective method of promoting mammography adherence. The very small aggregate effect size is similar to effect sizes found from meta-analyses of patient letter reminders for cervical cancer screening (OR = 1.64; Tseng et al., 2001
) and of tailored self-help materials promoting smoking cessation (OR = 1.42; Lancaster and Stead, 2006
). The small size may be due to an increase in mammography rates in the general population (Legler, 2002
). Even a small effect size is noteworthy when considering the potential to improve the prognosis of the approximately 200,000 US women who are diagnosed with breast cancer each year (American Cancer Society, 2006
Interventions directed at women of minority ethnicities and/or low incomes were no more effective than those that were not. This implies that tailored interventions may work equally well in populations with lower rates of mammography screening as they do in the general population. Women who regularly followed mammography screening guidelines were similarly influenced by the tailored interventions as women who did not. There may still be a subpopulation of the nonadherent group who has never
had a mammogram that may be especially difficult to influence, however (Champion et al., 2003
Our prediction that the more individualized a tailored message is, the more effective it will be, was partially supported. Of the factors age, ethnicity, barriers to care, risk factors, the HBM, the TTM, and/or motivational interviewing, only interventions that tailored by the HBM were found to be more effective. The HBM model involves tailoring to perceptions of risk, benefits, severity, barriers, cues to action and self-efficacy, whereas tailoring to just barriers or the stage of change is more limited.
Another consideration is that the TTM was operationally defined in a variety of ways and was applied in interventions that varied in their level of elaborateness. For example, the maintenance stage was defined as receiving mammograms two years in a row (Prochaska et al., 2005
), and as receiving two mammograms in four years (Messina et al., 2002
). One study simply mailed a different packet of information to participants based on their stage of change (Prochaska et al., 2005
). In contrast, another study applied the TTM by using computer-assisted telephone interviewing and adjusted responses based on the participant’s stage of change, in addition to sending a follow-up mailing according to participant’s new stage of change after the intervention (Crane et al., 1998b
). Variation in use of the TTM to promote cancer screening behaviors is discussed in greater detail in a recent review (Spencer et al., 2005
). Similarly, the content included in the motivational interviewing interventions also varied.
Tailoring an intervention by ethnicity was significantly worse
than not tailoring by ethnicity. The four studies that did so did not explicitly define what the tailoring entailed. One implied that ethnicity was included in calculating risk (Jibaja-Weiss et al., 2003
) and another reported that it used “ethnicity-appropriate” art (Rimer et al., 1999
). The interventions were tailored to various ethnicities including African-American, Asian-American, Mexican-American, and non-Hispanic white women, and also by a variety of additional factors (i.e., age, risk factors, barriers, the TTM, motivational interviewing), so it is difficult to explain why they were less effective. The authors of the study with the lowest effect size, which may have driven the significantly negative aggregate result, suggested that the content of their message about cancer risk may have been too overwhelming (Jibaja-Weiss et al., 2003
To interpret the effects of mode of implementation and variables for which the interventions were tailored, one needs to consider how these moderators were related. The fact that interventions delivered in-person were likely to use the HBM and that interventions that used the HBM often included a physician recommendation, makes it difficult to interpret which of these aspects of the interventions may be driving the effect. Our hypothesis that the more personal contact involved the more effective an intervention would be was not supported. However, additional non-tailored modalities included in some interventions may have played a role.
Consistent with our hypothesis and previous investigations (Legler et al., 2002
; Jepson et al., 2000
), including a physician recommendation in the intervention significantly increased the effect size. Clearly, the authority of a physician has a powerful impact on a woman’s adherence to mammography screening guidelines and should be incorporated into tailored interventions whenever possible.
Our expectation that having an active control group would result in lower effect sizes, compared to having a no-treatment control group, was not supported. Although one might expect that there would be a greater difference if the control group was given no intervention, it is likely that even women in this condition encountered some mammography information.
The result that studies using recent mammography to define adherence had higher effect sizes than those that used repeat/regular mammograms conformed to our prediction. The use of the repeat/regular mammography as an index of adherence is relatively new, and is considered superior because repeat screening is expected to have the greatest impact on breast cancer mortality (Rakowski et al., 2003
). Determining the overall number of women who receive repeat or regular mammography screening is a challenge, however, because of the variety of definitions that have been used (Clark et al., 2002
Consistent with our expectations, the other outcome moderator, whether the study outcomes were confirmed by medical records or measured by self-report, did not significantly influence the effect size. Therefore, although there has been some skepticism regarding the validity of self-reports (Lawrence et al., 1999
), this finding, lends more support for the reliability of self-report methods to assess mammography use.
One limitation of this meta-analysis is the small number of studies compared to draw conclusions for some of the moderators. For example, there were only four studies that delivered their interventions in-person. Therefore, although the weighted aggregate odds ratio was considerably higher than those for the other modes of implementation, there was little power to detect an effect that may have been present. As the field develops and more studies in this area become available, it may be valuable to repeat these analyses.
The correlations among some of the moderators made it difficult to distinguish among the most effective characteristics. Therefore, further research may need to tease apart if using the HBM and a physician recommendation are both effective aspects of a tailored intervention to promote mammography screening, or if one of these characteristics can be isolated as the most important.
Since tailoring interventions was demonstrated to be an effective method of promoting mammography screening, we encourage investigators to continue applying this method, while improving the standardization of the definitions of tailored interventions used and the outcomes measured. Some studies we reviewed stated that they were culturally tailored
when they were actually only targeted to a cultural group (Gotay et al., 2000
; Kim, 2001
). Culturally targeted
interventions use a single version of the intervention that is the same for a group of people, but take important characteristics of this group into account. Culturally tailored
interventions consider important characteristics of a specific group, but tailor to individuals within these groups based on how they vary on these characteristics (Kreuter et al., 2003
). Also, repeat/regular mammography adherence should be regarded as the new standard of measuring mammography adherence in future work. Until there is a consensus on the screening recommendations, the definition used by the BCSC (Stoddard et al., 2002
) considering a woman’s mammography as regular if she has two screenings in four years would be inclusive of women following any guidelines.
In addition, although this meta-analysis is the first to explore the effectiveness of multiple forms of tailored interventions in detail, perhaps measuring mammography adherence alone does not capture the full impact of tailored information. For example, participants may be more confident about having a mammogram when they are more informed about the procedure. One of the studies included in this meta-analysis conducted by Rimer et al. (2001)
found that the combination of tailored print communication with tailored telephone counseling was significantly beneficial for contributing to knowledge and accuracy of risk perceptions. Rimer suggested that there is more stress surrounding mammography utilization following the recent controversy over age recommendations, creating a great need for interventions to aid women in mammography decision making. Finally, future research could apply findings from interventions used to promote mammography screening to creating interventions to encourage following-up with a physician after screening results (Bish et al., 2005