Gender differences in clinical trials of binge eating disorder: An analysis of aggregated data.

Although the rates of binge eating disorder (BED), in contrast to other eating disorders (EDs), are comparable between men and women (Striegel-Moore & Franko, 2003), research investigating gender differences in baseline and outcome symptoms in clinical trials for BED is severely limited by the underrepresentation of males in published studies (Striegel, Bedrosian, Wang & Schwartz, 2012; Thompson-Brenner et al., 2013). Community samples of women are more likely to receive treatment for BED despite these comparable rates of diagnoses (Kessler et al., 2013) and it is theorized that this may be due to lower awareness of EDs in men and/or greater reluctance in men to seek treatment for a “female” disorder (Striegel et al., 2012). A small number of studies have examined baseline differences in eating disorder (ED) pathology between males and females with BED in clinical samples (Barry, Grilo, & Masheb, 2002; Guerdjokova, McElroy, Kotwal, & Keck, 2007; Tanofsky, Wilfley, Spurrell, Welch, & Brownell, 1997). A few significant gender differences have been found, higher body dissatisfaction, drive for thinness, dietary restraint and emotional eating among women (Barry et al., 2002; Tanofsky et al., 1997). No consistent pattern of differences in the Eating Disorder Examination cognitive subscales (shape concern, weight concern, and eating concern; Fairburn & Cooper, 1993) have been identified; however, studies investigating differences in these variables have been underpowered to find them (Barry et al., 2002; Tanofsky et al., 1997). The few studies that have examined gender differences in BED treatment outcome have not found significant differences associated with gender, although all were also underpowered to detect these effects (e.g., Munsch et al., 2007; Safer, Hagler-Robinson & Jo, 2010; Ricca et al., 2010). For example, in the three studies cited above, the subsamples of male participants with BED ranged from n = 9 to 17, while the subsamples of female participants from n = 86 to 127. Other studies have shown that ED-associated psychopathology such as pre-treatment concerns with shape and weight predict treatment outcome in BED (e.g., Masheb & Grilo, 2008, Peterson, Crow, Nugent, Engbloom, & Mussell, 2000); however, baseline gender differences in these factors have not been linked to gender differences in outcome. It is essential to better understand treatment outcome among men with BED. Differences in baseline symptoms and treatment response may help guide the design of more effective treatments that will better address the clinical presentation of BED in men (Striegel et al., 2012). To address the observed underrepresentation of males in clinical trials, and to guide the design and hypotheses of future studies including more males, this study aimed to investigate gender differences in an aggregated database of multiple clinical trials. The specific aims were to investigate gender differences in baseline symptoms and treatment outcome, and to examine how gender may moderate response to common treatment parameters (i.e., length of treatment, group vs. individual treatment, self-help vs. therapist-led).