Stage-based lifestyle interventions in primary care: are they effective?

BACKGROUND: To systematically review the literature concerning the effect of stages-of-change-based interventions in primary care on smoking, physical activity, and dietary behavior. METHODS: An extensive search (until July 2002) was performed using the following inclusion criteria: (1) (randomized) controlled trial (RCT/CT), (2) intervention initiated in primary care, (3) and intervention aimed at changing smoking, physical activity, or dietary behavior, and stages-of-change-based outcomes, and (4) behavioral outcomes. Methodologic quality was assessed, and conclusions on the effectiveness at short-, medium-, and long-term follow-up were based on a rating system of five levels of evidence. Odds ratios were calculated when methodologically appropriate. RESULTS: A total of 29 trials were selected for inclusion. Thirteen studies included a physical activity intervention, 14 aimed at smoking cessation, and five included a dietary intervention. Overall methodologic quality was good. No evidence was found for an effect on stages of change and actual levels of physical activity. Based on the strength of the evidence, limited to no evidence was found for an effect on stages of change for smoking and smoking quit rates. Odds ratios for quitting smoking showed a positive trend. Strong evidence was found for an effect on fat intake at short- and long-term follow-up. Limited evidence was found for an effect on stages of change for fat intake at short-term follow-up. CONCLUSIONS: The scientific evidence for the effect of stages-of-change-based lifestyle interventions in primary care is limited. Limiting aspects in the stages-of-change concept with respect to complex behaviors as physical activity and dietary behavior are discussed