Behavioural counselling in general practice for the promotion of healthy behaviour among adults at increased risk of coronary heart disease: randomised trial.(Plus commentary)(Statistical Data Included)

Abstract

Objective To measure the effect of behaviourally oriented counselling in general practice on healthy behaviour and biological risk factors in patients at increased risk of coronary heart disease.

Design Cluster randomised controlled trial.

Participants 883 men and women selected for the presence of one or more modifiable risk factors: regular cigarette smoking, high serum cholesterol concentration (6.5-9.0 mmol/l), and high body mass index (25-35) combined with low physical activity.

Intervention Brief behavioural counselling, on the basis of the stage of change model, carried out by practice nurses to reduce smoking and dietary fat intake and to increase regular physical activity.

Main outcome measures Questionnaire measures of diet, exercise, and smoking habits, and blood pressure, serum total cholesterol concentration, weight, body mass index, and smoking cessation (with biochemical validation) at 4 and 12 months.

Results Favourable differences were recorded in the intervention group for dietary fat intake, regular exercise, and cigarettes smoked per day at 4 and 12 months. Systolic blood pressure was reduced to a greater extent in the intervention group at 4 but not at 12 months. No differences were found between groups in changes in total serum cholesterol concentration, weight, body mass index, diastolic pressure, or smoking cessation.

Conclusions Brief behavioural counselling by practice nurses led to improvements in healthy behaviour. More extended counselling to help patients sustain and build on behaviour changes may be required before differences in biological risk factors emerge.

Introduction

Lifestyle change is central to health promotion and the prevention of coronary heart disease.[1 2] TWO large trials of coronary heart disease prevention, the family heart and OXCHECK studies,[3 4] have been particularly influential in British general practice. Although both showed small but significant effects on risk of coronary heart disease, the results called into question the cost effectiveness of health promotion in the general practice setting.[5] Neither study concerned either patients at increased risk of coronary heart disease or behaviourally oriented counselling.[1 6] Lengthier programmes to alter smoking habits, diet, and physical activity have more substantial effects.[7-9] Counselling directed at behavioural and attitudinal change may produce greater changes than traditional educational approaches to health promotion, particularly when tailored to the individual's readiness to change.[10-12] We describe the effects on behaviour and cardiovascular risk factors of behaviourally oriented counselling on the basis of the stage of change model.[13] This model categorises patients into stages of readiness to change behaviour (from precontemplation through contemplation, preparation, and action, to the maintenance of change), with different types of advice and skill training being appropriate at different stages. The intervention was carried out by practice nurses in patients at increased risk of coronary heart disease. It was hypothesised that compared with control, behavioural counselling would lead to greater reductions in smoking and dietary fat intake and increases in regular physical activity, together with greater reductions in blood pressure, serum total cholesterol concentration, weight, and body mass index.

Participants and methods

The design of this parallel group randomised trial has been described elsewhere.[14] Twenty general practices were allocated to intervention and control conditions (see website) using the minimisation technique[15] to balance groups for the Jarman score of social deprivation,[16] ratio of patient to practice nurse hours per week, and fundholding status (including wave of entry).

Patients were recruited on the basis of one or more modifiable cardiovascular risk factors: regular cigarette smoking (more than one cigarette per day), high serum cholesterol cocentration (6.5-9.0 mmol/l), or combined high body mass index (25-35) and low physical activity (fewer than 12 episodes of vigorous or moderate exercise for at least 20 minutes in the past 4 weeks, according to criteria based on the national fitness survey).[17] Patients were excluded if they were on active follow up or drugs for coronary heart disease, had had cardiovascular disease or peripheral vascular disease, had a serious chronic illness, or were prescribed a special diet or lipid lowering drugs.

The target sample size was 100 patients per practice. Taking intracluster correlations of risk factors into account, we calculated that this would detect a drop in smoking prevalence from 50% to 41%, and a decrease of 0.27 mmol/l in total serum cholesterol concentration with 90% power at the 5% significance level.

After recruitment and baseline assessment patients were counselled by practice nurses in smoking cessation, dietary fat reduction, and increasing physical exercise as appropriate either using behaviorally oriented methods (intervention group) or …