A randomised control trial comparing lifestyle groups, individual ...

International Journal of Obesity (2006) 30, 1557–1564 & 2006 Nature Publishing Group All rights reserved 0307-0565/06 $30.00 www.nature.com/ijo

ORIGINAL ARTICLE A randomised control trial comparing lifestyle groups, individual counselling and written information in the management of weight and health outcomes over 12 months S Ash1,4, M Reeves1,4, J Bauer2,4, T Dover1, A Vivanti1,4, C Leong1, T O’Moore Sullivan2,3 and S Capra4 1 Princess Alexandra Hospital and Health Service District, Woolloongabba, Brisbane, Australia; 2The Wesley Hospital, Chasely St, Auchenflower, Brisbane, Australia; 3Centre for Diabetes and Endocrine Research, School of Medicine, University of Queensland, Queensland, Australia and 4Centre for Health Research, Queensland University of Technology, Australia

Objective: To investigate the effect of an 8-week group-based cognitive behaviour therapy lifestyle intervention with monthly follow-up to 6 months and further follow up at 12 months on change in weight and other weight-related variables, change in physical activity and change in health and well being compared to individualised dietetic treatment or giving an information booklet only (BO). Design: A randomised controlled trial of two intervention groups, a group-based cognitive behaviour therapy lifestyle intervention, Fat Booters Incorporated – (FBI) and individualised dietetic treatment (IDT) and control group receiving an information booklet only (BO). The intervention groups involved weekly contact for 8 weeks with monthly follow-up to 6 months and further follow-up at 12 months, conducted in real practice setting. Subjects: A total of 176 adults with body mass index (BMI)427 kg/m2, mean (7s.d.) age 48713 years, mean BMI 3475.5 kg/m2. Main outcome measures: Weight, percent body fat, waist circumference, physical activity, health status, self-efficacy and satisfaction with life were measured at baseline, 3, 6 and 12 months. Results: A statistically significant difference between groups was observed for weight change over time (P ¼ 0.05). The change in weight (mean7s.e.) for the FBI group was significantly greater than the BO group at 3 and 12 months (2.870.7 compared to 1.070.6 kg, Po0.05 and 2.970.9 compared to þ 0.570.9 kg, Po0.005, respectively). Change in weight in the IDT group did not differ from the FBI group at any time point. For all groups, waist circumference was significantly less than baseline at all time points (Po0.001). Significant differences in self-efficacy were observed over time (P ¼ 0.02), with both intervention groups having greater self-efficacy than the BO group. Significant drop-outs occurred over time for all three groups. Conclusions: A cognitive behaviour-based lifestyle intervention was more effective than providing an information booklet alone and as effective as intensive individualised dietetic intervention in weight loss and improvements in self-efficacy. International Journal of Obesity (2006) 30, 1557–1564. doi:10.1038/sj.ijo.0803263; published online 14 March 2006 Keywords: lifestyle group; weight loss; dietetic counselling; cognitive behaviour therapy; costs

Introduction Overweight and obesity have grown to be one of the major public health problems of the 21st century, both in Correspondence: Professor S Ash, Centre for Health Research, Queensland University of Technology, Victoria Park Rd, Kelvin Grove, Brisbane, Queensland 4059, Australia. E-mail: [email protected] Received 25 May 2005; revised 12 December 2005; accepted 9 January 2006; published online 14 March 2006

developed and developing countries.1 Recent national data indicate that approximately 60% of the adult Australian population is overweight or obese.2 Obesity per se has now been recognised as an independent chronic condition, which contributes over 4% to the burden of disease in Australia.3 Combined with lack of physical activity, which contributes 7%, this is an overall contribution of 11%. The true cost of this burden of disease has been estimated at A$680–1239m from the impact of obesity and overweight alone.4

Weight loss in lifestyle groups over 12 months S Ash et al

1558 Intervention studies for the management of overweight and obesity have shown disappointing results long term; however, a review of many studies has shown confounding due to poor study design.5,6 On the other hand, lifestyle interventions resulting in weight losses of 3–5 kg, have been effective in the prevention or delay of disease.7–9 Intervention studies now focus on small, sustainable losses of weight in the order of 5–10%.10 Evidence-based guidelines for weight management recommend energy restriction, combined with increase in exercise and behaviour therapy.11,12 Failure of patients complying with prescriptive medical advice has been linked to the style of treatment. Disease management styles, which centre around the patient and their goals have resulted in better adherence to treatment protocols, reduced morbidity and improved quality of life.13 Use of chronic disease self-management and patient-centred care approaches is also important in the management of weight. These approaches include shared goal setting, developing action plans, teaching skills and regular follow-up.14 Studies demonstrating success in weight loss are usually conducted in tightly controlled clinical trial settings. Most have invested large resources in the form of financial incentives for attending programmes,15 for meal replacements16 or for medications in drug trials.17 When these methods are translated to real practice settings the results are often disappointing, calling experts to recommend more ‘effectiveness’ rather than ‘efficacy’-based research.1 Effectiveness research focuses on the reach, efficacy, adoption, implementation and maintenance (RE-AIM) of a programme in real-world settings.18 This research is conducted so that its results have external validity, generalisability and sustainability in real practice. Unlike efficacy interventions, effectivenessbased research (i) uses heterogeneous, representative samples with few exclusion criteria; (ii) uses brief feasible interventions which are adaptable to different settings; (iii) uses a variety of staff with competing demands to implement the interventions; and (iv) focuses on maintaining the ability of the setting to continue the intervention as standard practice. The current study was designed to reflect real-clinical practice. This study aimed to demonstrate that (1) group-based cognitive behaviour therapy intervention is more effective at reducing weight and other weight related variables, increasing physical activity and improving health and well-being than individualised dietetic treatment (IDT) or giving an information booklet only (BO), at 3 months, and (2) groupbased cognitive behaviour therapy intervention is more effective at maintaining these changes than IDT or giving booklet information only, at 12 months.

Materials and methods Study design The study was a randomised-controlled 12-month trial conducted between two tertiary hospitals (public and International Journal of Obesity

private) between February 2002 and July 2003. The trial replaced the previous hospital outpatient service for weight management at the public hospital but was a new service at the private facility, which previously had not provided any ambulatory care services. A project manager (TD) was employed to manage the recruitment, randomisation of subjects and maintenance of data. A total of 13 dietitians and nutrition staff employed by the two sites, collected patient data and provided the group facilitation, dietetic intervention and follow-up. A group facilitation manual was provided for the groups and all facilitators were trained prior to the trial commencing. A standard protocol was developed for use in the IDT. Figure 1 shows the outline of the study design. Outcome data were collected at baseline, 3 months, 6 months and 12 months. The study received ethical approval from the participating institutions’ ethics committees. All subjects received written and oral information about the study prior to consenting.

Study participants Overweight and obese men and women (body mass index BMIX27 kg/m2) were recruited for participation in the study from current hospital referrals and by advertising in local community newspapers. Exclusion criteria included BMI o27 kg/m2, o18 years of age, from non-English speaking background requiring an interpreter or cognitive impairment. Potential participants were not excluded based on medical condition(s) or medication(s). Randomisation After screening for exclusion criteria and following informed consent, participants were randomised by the project manager, using a random number table, into one of three intervention groups at one of two hospital sites. The allocation ratio for the two hospital sites (public and private) was 2:1 due to available resources for implementing the intervention. Dietary interventions Participants in all three groups were required to purchase a nutrition resource booklet based on cognitive behaviour therapy principles.19 Participants assigned to the Fat Booters Incorporated (FBI) group attended an 8-week (112 h per week for 6 weeks with follow-up at 8 weeks) lifestyle behaviour management group, with 10–12 participants per group. The group programme used a tri-phasic design involving knowledge and skill development, cognitive behaviour therapy and relapse prevention with a focus on improvements in self-concept, self-efficacy and skills mastery. It emphasised empowerment, development of self-efficacy and skills, with a non-directive approach taken by facilitators. While information was available about diet and exercise, it was up to individuals if they acted on this information in making changes to their lifestyle.


1559

Figure 1 Study design and intention to treat analysis protocol.

Following completion of the programme, FBI participants attended a follow-up visit at week 8 and then monthly until 6 months. Attendance at each session during the initial intervention and at follow-up was recorded. Participants assigned to the IDT group, were provided with individualised weekly contact with a dietitian for 8 weeks. This included an initial nutrition assessment, provision of an individualised diet prescription (aiming to achieve a weight loss of 0.5–1 kg/week), and an exercise prescription (20– 30 min of accumulated exercise most days of the week). Individualised dietetic treatment participants attended monthly follow-up visits from week 8 to 6 months. Attendance at each session during the initial intervention and at follow-up was recorded. If a patient was unable to attend the clinic for an appointment, an attempt was made to provide the intervention via the telephone for that appointment. Participants in the BO group acted as the control group and were provided with no further nutritional advice other than the nutrition resource booklet. Follow-up for those in the BO group occurred at 3, 6 and 12 months.

Outcome measures All outcome measures for all participants, in all groups, were assessed at baseline, 3 months, 6 months and 12 months. Weight and body composition were measured using foot-tofoot bioelectrical impedance analysis (Model TBF-410, Tanita Inc., Tokyo, Japan). Weight and per cent body fat were measured without shoes or heavy clothing to the nearest 0.1 kg and 0.1%, respectively. Height was measured by a fixed stadiometer, without shoes, to the nearest 0.5 cm. Body mass index was calculated from weight in kilograms divided by height in meters squared. Waist circumference was measured with a non-expandable tape at the point of the umbilicus, to the nearest 0.5 cm. Physical activity level was assessed using the short format International Physical Activity Questionnaire (IPAQ).20 The questionnaire collected information on the number of days and amount of time spent (when 410 min) on vigorous activities, moderate activities and walking in the past 7 days. Participants were categorised as ‘sufficiently active’ or ‘not sufficiently active’. Sufficient activity was defined as five or more days of moderate activity or walking of at least 30 min International Journal of Obesity


1560 per day (150 min per week) or 3 or more days of vigorous activity of at least 20 min per day. These criteria are based on national and international recommendations for the minimum amount of physical activity required for good health.21 The reported test–retest reliability Spearman’s correlation coefficient of the questionnaire was 0.80 and median criterion validity correlation against an accelerometer was 0.30.20 The health status questionnaires were chosen to reflect what was routinely used in psychology practice at the time of the study. The questionnaires were also chosen because there was no cost involved in their usage and they were short and simple for patients to complete within practice. This was seen as a major advantage in the programme’s applicability to the real world. Health status was measured using the General Health Questionnaire (GHQ-12).22 The GHQ-12 is a 12-item scale for measuring non-psychotic disorders and is one of the most widely used questionnaires to test psychological well being. The questionnaire has 12 items which are rated on a four-point scale (with lower scores reflecting better well being). The GHQ-12 has shown a sensitivity of 76.3%, specificity of 83.4% and a positive predictive value of 52.9% when compared against the Composite International Diagnostic Interview (CIDI). Internal consistency is ranked at a ¼ 0.820.86. The questionnaire is usually used as a continuous scale (0–12) with 0 indicating good health; however, due to non-normal distribution of this variable in our study participants, scores on the GHQ-12 were categorised into two categories – good health (0) and not in good health (X1). Self-efficacy was assessed using the General Self Efficacy Scale (GSES), a 10-item, four-point Likert scale. The GSES has shown test–retest reliability of r ¼ 0.67, internal consistency between a ¼ 0.75–0.91 and convergent validity of r ¼ 0.45– 0.49 when correlated with measures of optimism and stress.23 The GSES has also been shown to predict behavioural intention and coping self-efficacy in a dietary study of adults in Germany.24 Overall scores range from 10 to 40, with a higher score indicating a higher level of self-efficacy. General well being was measured using the Satisfaction with Life Scale (SWLS).25 The SWLS is a five-item, sevenpoint Likert scale. Individual items are summed for an overall score ranging from 5 to 35, with a higher score indicating better well being. The Satisfaction With Life Scale has shown an internal consistency of 0.8, 2-month test– retest reliability of 0.82 and low to moderate concurrent validity.26 The SWLS has been shown to be a reliable and valid measure of overall quality of life.

Statistical analysis General descriptive and bivariate statistical analyses were carried out using SPSS for Windows (Version 11.00, 2003, SPSS Inc., Chicago, IL, USA). Continuous variables were tested for normal distribution. Data are presented as means7s.d. or s.e. for continuous variables and counts International Journal of Obesity

(percentages) for categorical variables. Analyses were carried out on an intention-to-treat basis. One-way analysis of variance (ANOVA) and Fisher’s exact test were used to determine whether dietary intervention groups differed at baseline and whether differences existed between those subjects for whom complete data were obtained and those who had missing data (incomplete or drop-outs). To examine changes in intervention groups over time and to maximise the amount of data that were used in the analysis the following analyses were completed; repeated measures analysis of variance regression models for continuous variables and repeated measures logistic regression models for categorical variables, using a generalised estimating equations approach (SUDAAN statistical package, Version 7.5, 1997, NC, USA). These analyses include all available data for each individual, thereby allowing an intention-to-treat analysis. The significance was set at Po0.05.

Results A total of 208 (n ¼ 208) participants were assessed for eligibility between January and July 2002 (Figure 1). Seventeen subjects, with BMIo27 kg/m2 (n ¼ 11) and cognitive impairment or lack of language skills (n ¼ 6) were excluded. One hundred and ninety one (191) participants were randomised into the three intervention groups of the study. Figure 1 shows the numbers of participants at enrolment, allocation, and follow-up in each group. Participants were analysed in the groups to which they were randomised and the amount of compliance to the intervention was not considered in the analysis. Baseline characteristics of participants did not differ significantly between the intervention groups (Table 1). Groups also did not differ with respect to employment status, highest level of education, living situation, previous weight loss and dieting at commencement of the study. Characteristics of participants differed slightly between the two hospital sites – participants at the public hospital had a significantly higher BMI (Fisher’s exact test P ¼ 0.02) and waist circumference (Fisher’s exact test P ¼ 0.04) than participants attending the private hospital. There was a significant difference in the amount of data available for participants between intervention groups (Fisher’s exact test, P ¼ 0.01). A greater number of participants in the BO group than expected were drop-outs, while more participants in the IDT group than expected had complete data. The amount of data available for participants did not differ significantly between hospital sites. There were significant differences in the available data for participants for gender, age, BMI and per cent body fat. Significantly more females than expected were drop-outs, compared to males (Fisher’s exact test, P ¼ 0.01). Drop-outs tended to be younger than participants for whom complete and incomplete data were available (F(2,158) ¼ 3.248, P ¼ 0.04). Participants who dropped out had a higher BMI (36.576.1 vs 33.875.4 kg/m2;


1561 F(2,173) ¼ 4.065, P ¼ 0.019) and per cent body fat (44.176.3 vs 39.476.9%; F(2,164) ¼ 6.331, P ¼ 0.002).

Weight, body mass index, per cent body fat and waist circumference Changes in weight, BMI, body fat and waist circumference between the three groups over the four time points are shown in Table 2. A statistically significant difference between the groups over time was evident for change in weight (Wald F6 ¼ 2.13, P ¼ 0.05). This was reflected in a difference in change in BMI between groups, which approached statistical significance (Wald F6 ¼ 2.1, P ¼ 0.06). Change in weight was compared to baseline and compared to FBI group. Significant differences in change in weight were observed between the BO and FBI group at 3 months (P ¼ 0.05) and 12 months (P ¼ 0.005). Change in weight in the IDT group did not differ from the FBI group at any of the time points. Change in per cent body fat and waist circumference did not differ between the three groups over the 12 months. For all participants, waist circumference was significantly lower than baseline level at each of the follow-up time points (Po0.001), however, per cent body fat was not significantly different from baseline at 3, 6 or 12 months.

Physical activity levels There appeared to be differences in the proportion of patients who were sufficiently active between the intervention groups over time, although not statistically significant (Wald F6 ¼ 11.46, P ¼ 0.075). Table 3 shows the odds of being sufficiently active in the IDT and BO groups at 3, 6 and 12 months, relative to baseline and the FBI group. Relative to the FBI group, the odds of being sufficiently active at 3 months compared to baseline were 0.27 (95% CI 0.07, 1.02) times lower in the IDT group (P ¼ 0.053) and 0.19 (95% CI 0.05, 0.77) times lower in the BO group (P ¼ 0.021). There were no further significant differences in physical activity level at 6 or 12 months. Health and well-being scales Health status and general well being did not differ between groups over time. Significant differences were observed for self-efficacy score between groups over the 12 months (Wald F6 ¼ 2.57, P ¼ 0.021). Table 4 shows the mean scores for the three groups. Mean self-efficacy score for BO group differed significantly to FBI group at 3 months (P ¼ 0.014) and 12 months (P ¼ 0.006). Table 2

Change in anthropometric variables over time 3 Months

Table 1

Baseline characteristics of participants by intervention group FBI

N Age (years) Gender (M:F) Weight (kg) BMI (kg/m2) Body fat (%) Waist (cm)

IDT

57 49713 19:38 94.6 716.8 33.774.6 39.676.4 111.5713.3

65 48713 16:49 95.4720.7 34.275.9 41.477.1 111.5716.2

BO 54 47714 12:42 101.6718.4 35.876.2 41.977.4 114.3717.3

GHQ -12 Good health Not good health General self-efficacy scale Satisfaction with life scale

24 (42.1%) 33 (57.9%) 3175 2278

27 (41.5%) 38 (58.5%) 3075 2077

22 (40.7%) 32 (59.3%) 3176 2277

Activity Insufficient Sufficient

22 (40.0%) 33 (60.0%)

27 (41.5%) 38 (58.5%)

21 (40.4%) 31 (59.6%)

Data are mean7s.d. or n (%). GHQ-12, General Health Questionnaire – 12 questions.

Table 3

FBI IDT BO

6 Months

12 Months

Weight (kg)a FBI 1.9 (0.5) (n ¼ 40) IDT 2.6 (0.4) (n ¼ 51) BO 1.4 (0.5)b (n ¼ 31)

2.8 (0.7) (n ¼ 32) 2.6 (0.5) (n ¼ 47) 1.0 (0.6) (n ¼ 24)

2.9 (0.9) (n ¼ 29) 1.8 (0.8) (n ¼ 49) 0.5 (0.9)c (n ¼ 24)

BMI (kg/m2) FBI 0.7 (0.2) (n ¼ 40) IDT 0.9 (0.1) (n ¼ 51) BO 0.5 (0.2) (n ¼ 31)

1.0 (0.2) (n ¼ 32) 0.9 (0.2) (n ¼ 47) 0.4 (0.2) (n ¼ 24)

1.0 (0.3) (n ¼ 29) 0.6 (0.3) (n ¼ 49) 0.2 (0.3) (n ¼ 24)

Body fat (%) FBI 0.2 (0.7) (n ¼ 37) IDT 0.4 (0.4) (n ¼ 51) BO 0.7 (0.5) (n ¼ 31)

0.0 (0.5) (n ¼ 32) 1.6 (0.5) (n ¼ 47) 0.4 (0.4) (n ¼ 24)

0.2 (0.8) (n ¼ 29) 1.3 (0.6) (n ¼ 48) 0.0 (0.5) (n ¼ 24)

Waist (cm) FBI 3.5 (0.6) (n ¼ 36) IDT 4.6 (0.9) (n ¼ 48) BO 3.5 (0.9) (n ¼ 30)

4.3 (0.9) (n ¼ 30) 4.8 (1.1) (n ¼ 47) 4.6 (1.5) (n ¼ 23)

5.8 (1.2) (n ¼ 28) 4.5 (1.1) (n ¼ 48) 3.1 (1.0) (n ¼ 24)

Abbreviations: FBI, Fat Booters Incorporation; IDT, individual dietetic treatment; BO, booklet only; BMI, body mass index. Values are mean (s.e.) for change from baseline. Data are compared to baseline and FBI group. aWald F6 ¼ 2.13, P ¼ 0.05. bP ¼ 0.05. cP ¼ 0.005.

Odds ratio (95% CI) of being sufficiently active compared to baseline 3 Months

6 Months

12 months

1.00 (n ¼ 38) 0.27 (0.07, 1.02) (n ¼ 51) 0.19 (0.05, 0.77)a (n ¼ 31)

1.00 (n ¼ 32) 0.62 (0.20, 1.92) (n ¼ 46) 0.47 (0.13, 1.69) (n ¼ 24)

1.00 (n ¼ 28) 0.73 (0.24, 2.22) (n ¼ 47) 2.15 (0.52, 8.84) (n ¼ 24)

Abbreviations: FBI, Fat Booters Incorporation; IDT, individual dietetic treatment; BO, booklet only. Data are compared to baseline and FBI group: overall Wald F6 ¼ 11.46, P ¼ 0.075. aP ¼ 0.021.

International Journal of Obesity


1562 Table 4

Mean (7s.e.) self-efficacy scores

FBI IDT BO

Baseline

3 Months

6 Months

12 Months

30.7 (0.6) (n ¼ 57) 30.5 (0.6) (n ¼ 65) 30.6 (0.8) (n ¼ 54)

32.2 (0.8) (n ¼ 38) 31.7 (0.6) (n ¼ 51) 29.6 (1.0)a (n ¼ 31)

30.8 (1.0) (n ¼ 32) 31.6 (0.6) (n ¼ 46) 29.5 (0.9) (n ¼ 24)

33.0 (0.8) (n ¼ 28) 32.9 (0.6) (n ¼ 48) 29.4 (1.2)b (n ¼ 24)

Abbreviations: FBI, Fat Booters Incorporation; IDT, individual dietetic treatment; BO, booklet only. Data are compared to baseline and FBI group: overall Wald F6 ¼ 2.57, P ¼ 0.021. aP ¼ 0.014. bP ¼ 0.006.

Discussion Obesity is an increasing problem worldwide, but particularly in Australia, where calls for government action to address the problem are evident.10 Few interventions, where weight loss is sustained and which address lifestyle issues, have been designed in real-practice settings or have been evaluated for long enough periods.1 Our study was designed to implement recent evidencebased guidelines for the management of overweight and obesity in a real-practice environment. We have demonstrated that an 8-week intensive lifestyle intervention, with monthly follow-up to 6 months could be conducted in a real-practice setting and produce modest results of 3 kg weight loss, which were sustained over 12 months. Our previous work also indicated greater weight losses in a tightly controlled research setting, however, these losses were not sustained over time.27 Other studies have indicated that the effects of lifestyle interventions are often modest.7,9 A randomised trial, which assigned 423 overweight people to a structured commercial weight loss programme or self-help programme, observed mean (7s.d.) weight loss of 4.3 (76.1) kg compared to 1.3 (76.1) kg at 12 months, and 2.9 (76.5) kg compared to 0.2 (76.5) kg at 2 years. Participants in the structured weight loss arm received incentives in the form of vouchers for the cost of the commercial programme and had contact with the researchers every 1–2 weeks over the 2-year period.15 In our study, there was no significant difference in weight loss between the two intervention groups over the 12 months. There was a trend however for the FBI group to maintain weight loss compared to the other two groups. It is therefore possible that the cognitive behaviour therapy programme used in the group provided better strategies for maintaining healthy behaviours long term. Leibbrand and Fichter28 found that weight loss following a 10-week behavioural intervention was sustained after 18 months, with and without follow-up support. They propose that the CBT strategies learned and reinforced in the 10-week behavioural intervention were sufficient to sustain weight loss without support for the follow-up period. The FBI group-based programme also took a patient centred approach, offering a structured way for participants to become expert in managing their lifestyle issues and chronic disease(s). Self-efficacy is enhanced when patients have a collaborative plan for self-care which includes an International Journal of Obesity

assessment of beliefs, barriers and supports; a personal action plan that identifies both goals and barriers; and an active follow-up plan that monitors progress, while providing support for the patient throughout.14 The effectiveness of the intervention in preventing further weight gain is evident in both the intervention groups compared to the control. Health authorities indicate that a mean weight loss of 1 kg in the Australian population would have major impact on health costs.29 Other studies have shown the effectiveness of dietetic intervention on minimising or delaying the costs of drug and other treatment in cardiovascular disease30 and diabetes.31 This study did not attempt to assess cost effectiveness using health economics modelling but it is clearly evident that implementation of the FBI programme in a real-practice setting is likely to be more cost efficient than standard individual dietetic counselling, while at the same time achieving similar outcomes over a 12-month period. Group-based interventions are able to manage more overweight patients over time compared to one-on-one individual interventions. The FBI programme can accommodate 10–12 participants, over 6–8 weeks (approximately 3 h per session). In the public hospital facility this programme has continued to run at least six sessions per year, so a minimum of 60–72 overweight people can be accommodated per year. For the same time frame of a 3-h clinic, the IDT programme, which includes a 1-h initial individual consultation, followed by seven 20-min weekly review sessions and four monthly follow-up sessions of 20 min, can manage only 25 people per year. It is estimated that the cost of providing dietetic service for weight management would range from $A253 to 415 per patient on an individual basis compared to $A106 to 117 per patient on a group basis. There were a number of limitations in this study. Firstly, there was a large attrition rate, particularly from the BO group, where only 37% of the initial sample had complete data. In a review of randomised control trials with at least 12month follow-up on advice on low-fat diets for obesity, 40% losses to follow-up were demonstrated with only 20% of subjects remaining in one study, which was extended to 18 months.32 While care is required in interpreting the results in such studies of weight loss, the high drop-out rate is not an unusual phenomenon. Every attempt was made to contact all participants at 12 months, unless consent had been withdrawn.


1563 There were also significant differences in gender, age, BMI and per cent body fat between participants with complete data, missing data and drop-outs, which have decreased the representativeness of our sample. To account for the missing data, results were analysed on an intentionto-treat basis using a generalised estimating equations approach. Secondly, the reported levels of sufficient physical activity by participants at baseline (57.9%) were considerably greater than the general Australian population (45.2%).33 This may be due to over-reporting by participants in this study or due to the potential over estimation of physical activity level using the IPAQ, which has been reported in other studies.34 The measurement error may have attenuated the true effect size of physical activity in this study. Finally, the study did not measure other clinical end points such as blood sugars, lipids or other markers of disease, so no conclusions can be drawn on the impact of the weight loss and increases in physical activity on improvements in health outcomes other than weight. Study strengths include being conducted under real-world clinical practice conditions. That is, minimal inclusion and exclusion criteria were applied, incentives were not provided and dietetic staff provided the interventions within normal workplace requirements. This is in contrast to previous studies, which have provided participants with enticing incentives to maintain involvement15 or applied stringent eligibility criteria,16,28 which limit generalisability of the results. In conclusion, a group-based lifestyle programme using cognitive behaviour therapy was more effective at reducing weight and improving self efficacy at 3 months and 12 months than the BO group, but not increasing physical activity or improving health and well being. The FBI programme was more effective at achieving weight loss and improving self-efficacy at 12 months compared to the BO group. Both the FBI and IDT groups sustained weight losses of 2–3 kg at 12 months. The FBI programme can be applied to both a public and private ambulatory setting and the structured nature of the FBI programme and the training manual provided can easily be learnt by health professionals and is flexible enough to be delivered by a range of practitioners. Added to this, we have shown that this type of programme is possible to conduct under real-work conditions, is more cost efficient and provides at least as good outcomes over 12 months as an intensive individualised approach.

Acknowledgements We wish to thank the Princess Alexandra Hospital Research and Development Foundation for assistance with funding and the following staff at the Princess Alexandra Hospital and Health Service District and The Wesley Hospital, who

participated in the trial: Wendy Chang, Kylie Clavarino, Susie Croaker, Lisa Farlow, Bev Gallagher, Ingrid Hickman, Helen Porteous, Louise Smith and Shelley Wilkinson.

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