Metabolic Syndrome in Obese Patients With Binge-Eating Disorder in Primary Care Clinics: A Cross-Sectional Study

The prevalence of obesity has reached epidemic proportions, with more than 1 in 3 adults in the United States considered obese (body mass index [BMI] ≥ 30 kg/m2).1 Degree of obesity is directly associated with metabolic syndrome, a cluster of vascular risk factors that increase the risk of cardiovascular disease, including hypertriglyceridemia, low serum high-density lipoprotein (HDL) cholesterol level, hypertension, elevated fasting blood glucose, and central adiposity.2,3 Metabolic syndrome is a major risk factor for cardiovascular disease, type II diabetes, and all-cause mortality4–6; has a significant negative impact on patients’ health-related quality of life7; and represents a growing health care economic burden in the United States.8 As rates of obesity have increased, so too has the prevalence of metabolic syndrome, with an estimated rate of 24% in the US population.9 Among obese individuals, rates of metabolic syndrome are much higher, with 50% of women and nearly 60% of men meeting criteria for metabolic syndrome.10 Significant ethnic differences also are present in the prevalence of metabolic syndrome. The age-adjusted prevalence of metabolic syndrome in the United States is 24.8% for men and 22.8% for women among whites, is 16.4% for men and 25.7% for women among blacks, and is highest among Hispanics (28.3% for men and 35.6% for women).9 Obesity is a heterogeneous problem with complex causes.11,12 Research has highlighted the particular clinical importance of a specific subgroup of obese persons who have binge-eating disorder (BED).13 BED is characterized by recurrent episodes of binge eating (overeating while experiencing a subjective loss of control) without inappropriate compensatory behaviors. BED is strongly associated with increased severity of obesity and with heightened risk for psychiatric and medical problems.13 In addition to binge eating and greater associated psychopathology,14,15 obese individuals with BED differ significantly from their non-BED counterparts in their non–binge-eating patterns and behaviors.16 Clinical Points ♦Metabolic syndrome is common in obese patients with binge-eating disorder (BED) in primary care settings. ♦It is important that primary care providers have open discussions with their obese patients regarding their excess weight and indicate that there are specific pharmacologic and behavioral treatments with demonstrated effectiveness for BED. ♦Preliminary evidence suggests that time spent dieting may buffer the development of metabolic syndrome within obese individuals with BED. Little is known about the relationship of specific eating behaviors/patterns characteristic of BED to metabolic syndrome. Research has found that certain eating behaviors associated with metabolic abnormalities are similar to some of the features characteristic of BED. For example, eating large amounts of food in a discrete period of time is associated with increased fasting glucose levels, exaggerated insulin secretion, elevated serum lipids, and decreased glucose tolerance.17,18 Eating rapidly is associated with higher waist-hip circumference ratio, elevated serum lipids, and fatty liver in obese individuals.19 In addition, irregular meal patterns are associated with metabolic syndrome in the general population.20 To date, only 3 published studies have investigated metabolic syndrome in obese persons with BED. The first study21 compared obese men and women with BED seeking weight loss treatment and found that 32% of participants met criteria for metabolic syndrome. This initial study, however, did not examine correlates of metabolic syndrome; moreover, the observed rate (32%) of metabolic syndrome was much lower than is generally found in obese populations.10 The second study22 found that 60% of obese patients seeking treatment for BED at a university-based research clinic met criteria for metabolic syndrome. Metabolic syndrome was significantly associated with fewer episodes of weight cycling (defined as intentional weight loss of ≥ 20 lb followed by weight regain) and regular meal skipping.22 Most recently, Hudson and colleagues23 followed a group of overweight and obese individuals with and without BED over a 5-year period and assessed metabolic syndrome components. Those with BED were significantly more likely than those without BED to self-report new diagnoses of metabolic syndrome components (eg, dyslipidemia, hypertension) at follow-up. Hudson and colleagues23 concluded that BED may confer added risk for metabolic abnormalities independent of overweight/obesity. Given the limited data on metabolic abnormalities in obese persons with BED, as well as the large discrepancies in reported rates of metabolic syndrome in previous studies, more research is needed to understand metabolic syndrome in BED. This research needs to be performed in general medical settings such as primary care clinics for several important reasons. Although obese patients with BED report greater medical concerns compared to obese non–binge eaters24 and are believed to be high utilizers of primary care facilities,25 research has found that primary care providers are unfamiliar with BED26 and frequently overlook this condition.25 There also is evidence suggesting that those with BED who present to primary care clinics may differ from those who present to specialty research clinics.27 Thus, the present study examined the frequency of metabolic syndrome in obese patients with BED recruited in primary care settings and extends previous work by exploring demographic and eating- and weight-related behavioral and psychological correlates of metabolic syndrome in this specific subgroup of obese persons.