Objective: To assess the long term effectiveness of the "green prescription" programme, a clinician based initiative in general practice that provides counselling on physical activity.
Design: Cluster randomised controlled trial. Practices were randomised before systematic screening and recruitment of patients.
Setting: 42 rural and urban general practices in one region of New Zealand.
Subjects: All sedentary 40-79 year old patients visiting their general practitioner during the study's recruitment period.
Intervention: General practitioners were prompted by the patient to give oral and written advice on physical activity during usual consultations. Exercise specialists continued support by telephone and post. Control patients received usual care.
Main outcome measures: Change in physical activity, quality of life (as measured by the "short form 36" (SF-36) questionnaire), cardiovascular risk (Framingham and D'Agostino equations), and blood pressure over a 12 month period.
Results: 74% (117/159) of general practitioners and 66% (878/1322) of screened eligible patients participated in the study. The follow up rate was 85% (750/878). Mean total energy expenditure increased by 9.4 kcal/kg/week (P=0.001) and leisure exercise by 2.7 kcal/kg/week (P=0.02) or 34 minutes/week more in the intervention group than in the control group (P=0.04). The proportion of the intervention group undertaking 2.5 hours/week of leisure exercise increased by 9.72% (P=0.003) more than in the control group (number needed to treat=10.3). SF-36 measures of self rated "general health," "role physical," "vitality," and "bodily pain" improved significantly more in the intervention group (P<0.05). A trend towards decreasing blood pressure became apparent but no significant difference in four year risk of coronary heart disease.
Conclusion: Counselling patients in general practice on exercise is effective in increasing physical activity and improving quality of life over 12 months.