Objective: To compare health benefits achieved in a transtheoretical model‐chronic disease (TM‐CD) minimal intervention for obesity vs. augmented usual care (AUC). Research Method and Procedures: This was a 2‐year, randomized clinical trial with overweight or obese men and women from 15 primary care sites. AUC (n = 336) included dietary and exercise advice, prescriptions, and three 24‐hour dietary recalls every 6 months. TM‐CD care (n = 329) included AUC elements plus “stage of change” (SOC) assessments for five target behaviors every other month, mailed SOC and target behavior—matched workbooks, and monthly telephone calls from a weight‐loss advisor. Weight change was the primary outcome. Results: Repeated measures models under the missing at random assumption yielded nonsignificant adjusted differences between the AUC and TM‐CD groups for weight change, waist circumference, energy intake or expenditure, blood pressure, and blood lipids. The pattern of change over time suggested that TM‐CD participants were trying harder to impact target behaviors during the first 6 to 12 months of the trial but relapsed afterward. Sixty percent of trial participants maintained their baseline weights for 18 to 24 months. Discussion: A combination of mailed patient materials and monthly telephone calls based on the transtheoretical model and some elements of chronic disease care is not powerful enough, relative to AUC, to alter target behaviors among overweight primary care patients in an obesogenic environment. AUC may be sufficient to maintain weights among at‐risk primary care patients.

Res. 2003;11:641-652. Objective: According to the Transtheoretical Model (TM), tailoring interventions to patients' readiness to change can enhance patient progress and help patients use therapeutic resources more effectively. However, tailoring an intervention depends on accurate assessment of patients' stage of change (SOC). This study describes a multi-item algorithm of SOC (M-SOC) for weight loss-related behaviors that attempts to overcome some of the conceptual and methodological difficulties encountered in previously SOC assessments. Research Methods: Data were collected from participants randomly assigned to the treatment arm of a clinical trial comparing a TM-based, cognitive-behavioral intervention with enhanced usual care for weight loss. Results: The stair-step relationships hypothesized by the TM between assessed SOC and key behavioral measures were found for all algorithms (p Ͻ 0.05), indicating that the M-SOC algorithm performs as well as single item algorithms. However, 50% fewer patients were classified in action or maintenance for dietary fat intake and portion control (p Ͻ 0.05) by the multiple-item algorithms, providing staging more consistent with the clinical presentation of obese individuals. In addition, logistic regression analyses indicated that the single-item algorithms were not sufficient predictors of these behavioral domains. Discussion: To the extent that treatment is guided by assessed SOC, there is potential for a considerable variability in interventions with different approaches to staging. For weight-loss interventions that target portion control and decreased fat intake, the multi-item SOC algorithms seem to be better guides for matching treatments to SOC.

No abstract

. CAPERS. Longitudinal relationship between elapsed time in the action stages of change and weight loss. Obes Res. 2004;12:1499-1508. Objective: The objective of this study was to examine the longitudinal relationship between the elapsed time in the action and maintenance stages of change for multiple target behaviors and weight loss or gain. Research Methods and Procedures:The research design was a prospective cohort study of overweight and obese primary care patients randomized to an obesity management intervention based on the Transtheoretical Model and a chronic disease paradigm. The target behaviors included increased planned exercise and usual physical activity, decreased dietary fat, increased fruit and vegetable consumption, and increased dietary portion control. The participants were 329 middle-aged men and women with elevated body mass indices recruited from 15 primary care practices in Northeastern Ohio; 28% of the participants were African Americans. The main outcomes were weight loss (5% or more) or weight gain (5% or more) after 18 or 24 months of follow-up. Results: There were significant (p Ͻ 0.05) longitudinal relationships between the number of periods (0 to 4) in action or maintenance for each of the five target behaviors, or a composite score taken across the five target behaviors, and weight loss. In all cases, there was a significant (p Ͻ 0.05) stepped (graded) relationship between the time in action or maintenance and weight loss (or gain). Discussion: The data support the concept of applying the Transtheoretical Model to the problem of managing obesity in primary care settings. The remaining challenge is to identify those factors that reliably move patients into the action and maintenance stages for long periods.