The Behavioral Risk Factor Surveillance System data were obtained from an independent household probability sample drawn from the noninstitutionalized U.S. adult population (aged ≥18 years) to assess the prevalence of key behavioral risk factors and chronic disease conditions in all U.S. states and territories annually (5
). The Kessler-6 (K6) scale, a six-item measure for nonspecific psychological distress (7
), correlates highly with the World Health Organization Comprehensive International Diagnostic Interview–Short Form (r
= 0.65) and Disability Assessment Schedule (r
= 0.67) for anxiety and mood disorders. The K6 scale has demonstrated an excellent internal consistency reliability (Cronbach's α = 0.89) (7
). People with a total score of the K6 scale ≥13 were considered to have SPD. A participant's treatment status for mental health problems was ascertained by a positive answer to the question, “Are you now taking medicine or receiving treatment from a doctor or other health professional for any type of mental health condition or emotional problem?”
Participants' diabetes status was determined by self-report. We examined the following variables as potential correlates: demographic and socioeconomic characteristics (sex, race/ethnicity, age, education, and employment status), health insurance, diabetes type (type 1, type 2 with use of insulin, and type 2 without use of insulin), diabetes duration, cardiovascular risk factors (obesity, high blood pressure, high cholesterol, current smoking, and no leisure-time physical activity), microvascular complications (foot sores and retinopathy), and macrovascular complications (myocardial infarction, angina or coronary heart disease, and stroke).
We estimated the crude prevalences of undertreatment for mental health problems and the prevalence ratios (PRs) and 95% CIs of each correlate using log-linear models with a robust error variance estimator (8
). We considered results to be statistically significant if P
≤ 0.05. All of the analyses were conducted with the use of SAS (Version 9.1; SAS, Cary, NC) and SUDAAN software (Release 9.0; RTI International, Research Triangle Park, NC) to account for the complex sampling design.