Introduction
Well-organised care, including regular recall and review of patients, prompting of doctors, feedback on goal attainment, and continuing medical education and guidelines, are associated with reductions in risk factors among people with type 2 diabetes [
1,
2]. In addition, intensive pharmacological treatment of risk factors can reduce cardiovascular morbidity and mortality [
3,
4]. However, these benefits depend on people with diabetes taking their medication as prescribed, eating a healthy diet, being physically active on a regular basis and avoiding smoking.
There is some evidence that patient education, training patients in self-management and using interventions incorporating well-specified behaviour change techniques can be effective, at least in the short term [
5]. However, only a minority of people with type 2 diabetes in the UK have attended a structured education programme to assist with behaviour change, and where attendance has occurred the effectiveness of the programme in practice is largely uncertain [
6].
The Early Activity In Diabetes (Early ACTID: ISRCTN92162869) and Action for Health Diabetes (Look-AHEAD: NCT00017953) trials have demonstrated beneficial effects on cardiovascular risk factors of adding intensive lifestyle interventions to the primary care of diabetes patients [
7,
8]. These studies were selective in their behavioural focus. Many previous studies have been conducted in research clinics or specialist settings and have not clearly characterised the comparison condition. Behavioural interventions and their hypothesised mechanisms of action are rarely clearly specified and the delivery of the intervention is not often assessed. Most trials have relied on self-reported measures of behaviour, which are imprecise and subject to recall bias, and do not assess adherence to medication. This limits evaluation of the effects of behavioural interventions independent of organisational and pharmacological components, and cannot inform subsequent integration of the most effective components into routine practice.
We aimed to address these uncertainties in the Anglo–Danish–Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care-Plus (ADDITION-Plus) trial by evaluating the effect of a theory-based behaviour change intervention delivered by trained and quality-assured lifestyle facilitators, external to the primary care team, on objectively measured health behaviours (physical activity, diet change, medication adherence and smoking) among people with recently diagnosed type 2 diabetes receiving intensive general practice care [
9].
Results
Figure
1 shows the trial profile. Participating practices were largely comparable with the average English practice in terms of list size, diabetes prevalence and general practice/nurse whole-time equivalents (data taken from the National Primary Care Database;
www.population-health.manchester.ac.uk/primarycare/npcrdc-archive/archive/ProjectDetail.cfm/ID/10.htm). However, the median (interquartile range) Index of Multiple Deprivation score for ADDITION-Plus practices (11.7 [6.6–15.5]) suggested that they served less deprived communities than the average English practice (21.2 [12.2–36.1]) (data taken from the UK National Primary Care Database). Four hundred and seventy-eight eligible participants were recruited to the study (intervention group
n = 239; comparison group
n = 239) and attended baseline measurement. Baseline characteristics were similar in the two trial groups (Table
1). The majority of ADDITION-Plus participants were white men with a mean age of 60 years. In all, 51% of participants were in full- or part-time employment, and 62% had attended full-time education after the age of 16 years. There was one death in the comparison group and two deaths in the intervention group within 13 months of recruitment. Of those still alive, 444/475 (93%; intervention group: 95%, comparison group: 92%) returned for follow-up health assessment after a mean of 1.1 years (SD 0.2). There was no significant difference in baseline characteristics between those who attended follow-up health assessment and those who did not (data not shown).
Table 1
Baseline characteristics of ADDITION-Plus trial participants (n = 478)
Mean age (SD), years | 59.8 (7.5) | 59.5 (7.5) |
Men | 148 (61.9) | 150 (62.8) |
White ethnicity | 234 (97.9) | 232 (97.1) |
In full- or part-time employment | 122/238 (51.3) | 123/239 (51.5) |
Full-time education after 16 years of age | 145/236 (61.4) | 146/236 (61.9) |
Objectively measured health behaviours
Table
2 shows the outcomes of objectively measured health behaviours. PAEE levels were similar in both groups at 1 year. We observed small increases in plasma vitamin C levels in both groups over 12 months, with levels approximating national trends (National Diet and Nutrition Survey 2002 [
39]) and not significantly differing by group. The proportion of smokers was similar in the intervention and comparison groups at 1 year, reflecting national smoking rates [
40]. There were no differences between groups in the proportion of patients prescribed metformin, simvastatin and atorvastatin (data not shown), the mean prescribed total daily dose of each drug (data not shown) and the plasma drug levels.
Table 2
Objectively measured health behaviours by study group and between-group differences at 1 year in the ADDITION-Plus trial
PAEE, kJ kg−1 day−1a
| 33.7 (15.9) (N = 212) | 35.2 (18.2) (N = 218) | +1.50 (−1.74, 4.74) | 0.36 |
Plasma vitamin C, μmol/l | 56.2 (25.1) (N = 216) | 53.4 (25.0) (N = 218) | −3.84 (−8.07, 0.38)b
| 0.07 |
Smoking, %; cotinine validated (n/N) | 13.2 (23/174) | 17.3 (34/197) | 1.37c (0.77, 2.43) | 0.28 |
Drug plasma level, μmol/l |
Metformin | 1,310.0 (741.7) (N = 82) | 1,190.5 (725.6) (N = 100) | −119.5 (−335.0, 95.9) | 0.28 |
Log simvastatind
| −1.07 (1.73) (N = 30) | −1.43 (1.45) (N = 42) | −0.36 (−1.10, 0.39) | 0.35 |
Log atorvastatind
| 1.07 (1.01) (N = 40) | 0.91 (1.02) (N = 32) | −0.16 (−0.63, 0.32) | 0.52 |
Self-reported health behaviours
Participants reported increases in levels of total physical activity and consumption of fruit, vegetables and fibre, and reduction in consumption of fat and alcohol over 1 year, with no significant difference between groups (Table
3). There was little change in the proportion smoking with no significant between-group differences. Self-reported adherence to general medication increased in both groups from baseline to 1 year follow-up. Medication adherence for both general and diabetes medication was high in both groups at 1 year (defined as a score of >23/25 on the MARS questionnaire), with no significant difference between groups. A significantly higher number of patients in the intervention than in the comparison group reported that they had made positive changes to their diet and physical activity in the preceding 12 months.
Table 3
Baseline and 1 year follow-up self-reported behaviours by study group and between-group differences in the ADDITION-Plus trial
Physical activity |
Total physical activity, MET h/week | 78.6 (48.0) | 80.1 (49.5) | 90.0 (55.1) | 95.2 (55.7) | +7.51 (−0.009, 15.0) |
Recreational activity, h/week | 9.63 (9.81) | 10.4 (10.6) | 12.0 (13.0) | 13.1 (12.9) | +1.46 (−0.40, 3.34)a
|
Vigorous activity, h/week | 1.03 (2.41) | 1.04 (2.81) | 1.33 (3.59) | 1.42 (3.39) | +0.23 (−0.32, 0.72)a
|
Time spent in sedentary activity, h/week | 38.7 (19.6) | 36.4 (17.7) | 35.3 (15.5) | 33.4 (16.3) | −0.60 (−2.57, 1.38) |
Television viewing, h/week | 24.4 (12.8) | 23.9 (11.7) | 24.0 (10.2) | 23.4 (10.3) | −0.20 (−1.49, 1.10) |
Proportion reporting change in physical activity at 1 year, % | – | 41.0 (91/222) | – | 74.9 (170/227) | 4.29 (2.87, 6.42)b
|
Diet |
Total fat, g/day | 68.7 (30.3) | 60.3 (23.3) | 68.3 (29.6) | 60.6 (22.2) | +0.41 (−3.11, 3.94) |
Fat as percentage of energy, % | 32.0 (6.2) | 31.2 (6.0) | 31.3 (5.7) | 30.4 (5.9) | −0.45 (−1.41, 0.51) |
Polyunsaturated:saturated fat ratio | 0.58 (0.23) | 0.67 (0.27) | 0.62 (0.28) | 0.68 (0.26) | −0.01 (−0.06, 0.03) |
Fibre, g/day | 18.6 (7.3) | 19.0 (7.3) | 18.6 (7.2) | 19.8 (7.0) | 0.82 (−0.31, 1.95) |
Plasma vitamin C, mg/day | 147.4 (71.2) | 145.5 (66.0) | 141.0 (72.2) | 146.2 (66.5) | 3.89 (−6.62, 14.40) |
Total energy, kJ | 7,966 (2,628) | 7,200 (2,092) | 8,099 (2,757) | 7,446 (2,110) | 188.0 (−136.5, 512.5) |
Fruit food group (11 items), g/day | 277 (197) | 312 (222) | 266 (198) | 312 (212) | 4.89 (−31.2, 41.2)a
|
Vegetable food group (19 items), g/day | 237 (128) | 246 (148) | 231 (161) | 247 (135) | 4.76 (−19.0, 26.4)a
|
Alcohol, units/week | 8.5 (14.3) | 7.3 (11.1) | 9.5 (13.6) | 7.8 (10.6) | −0.25 (−1.45, 1.24)a
|
Proportion reporting change in diet at 1 year, % | – | 57.2 (127/222) | – | 77.4 (175/226) | 2.57 (1.70, 3.87)b
|
Smoking |
Self-reported smokers, % | 14.0 (31/222) | 11.7 (26/222) | 15.0 (34/227) | 15.0 (34/227) | 2.63 (0.76, 9.05)b
|
Medication adherence |
Adhering to hypoglycaemic medication, %c
| – | 81.2 (108/133) | – | 85.7 (132/154) | 1.39 (0.74, 2.60)b
|
Adhering to general medication, %c
| 73.1 (147/201) | 75.6 (161/213) | 69.5 (148/213) | 78.4 (174/222) | 1.25 (0.79, 1.99)b
|
Clinical and biochemical measures
Table
4 shows the baseline and follow-up anthropometric, clinical and biochemical measures. We observed small reductions in cardiovascular risk factors in both groups over 1 year. The majority of between-group differences favoured the intervention group but none achieved statistical significance.
Table 4
Baseline and follow-up anthropometric, clinical and biochemical measures by study group and between-group differences in the ADDITION-Plus trial
BMI, kg/m2
| 32.8 (5.7) | 32.3 (5.7) | 32.7 (5.3) | 32.1 (5.2) | −0.11 (−0.44, 0.22) |
Waist circumference, cm | 110.7 (15.1) | 109.5 (15.2) | 110.9 (12.4) | 109.1 (11.8) | −0.63 (−1.70, 0.44) |
Body fat, % | 42.1 (11.9) | 41.8 (11.2) | 42.8 (12.3) | 42.0 (11.8) | −0.30 (−1.72, 1.12) |
Systolic BP, mmHg | 134.4 (19.3) | 128.3 (17.4) | 138.2 (19.1) | 132.1 (17.4) | 1.76 (−0.92, 4.43) |
Diastolic BP, mmHg | 79.1 (10.9) | 75.1 (9.8) | 81.6 (10.0) | 77.7 (8.8) | 1.43 (−0.07, 2.92) |
Cardiorespiratory fitness, ml/kg/min | – | 30.9 (9.5) | – | 30.3 (8.6) | −0.61 (−2.63, 1.42) |
HbA1c, % | 7.01 (1.23) | 6.67 (0.95) | 7.23 (1.62) | 6.66 (0.94) | −0.09 (−0.25, 0.07) |
HbA1c, mmol/mol | 53.1 | 49.4 | 55.5 | 49.3 | |
Total cholesterol, mmol/l | 4.90 (1.16) | 4.31 (0.86) | 4.96 (0.98) | 4.33 (0.91) | −0.005 (−0.16, 0.15) |
HDL-cholesterol, mmol/l | 1.20 (0.35) | 1.19 (0.32) | 1.17 (0.35) | 1.19 (0.31) | 0.02 (−0.02, 0.05) |
LDL-cholesterol, mmol/l | 2.87 (0.99) | 2.34 (0.76) | 2.89 (0.91) | 2.29 (0.77) | −0.06 (−0.19, 0.08) |
Log10 triacylglycerol, mmol/l | 0.23 (0.24) | 0.21 (0.23) | 0.28 (0.22) | 0.24 (0.24) | −0.006 (−0.04, 0.03) |
Log10 alanine aminotransferase | 1.61 (0.19) | 1.53 (0.18) | 1.63 (0.21) | 1.53 (0.19) | −0.01 (−0.04, 0.02) |
Microalbuminuria, %a
| 20.2% (43/213) | 16.1% (35/217) | 18.6% (41/220) | 17.5% (39/223) | 1.22 (0.68, 2.17)b
|
Rose angina questionnaire, % positive | – | 12.2% (27/222) | – | 12.0% (27/225) | 0.98 (0.56, 1.74) b
|
Michigan neuropathy score | 1.91 (1.67) | 1.91 (1.88) | 1.84 (1.61) | 1.78 (1.71) | −0.08 (−0.34, 0.18) |
Log10 UKPDS 10 year CVD riskc
| −0.63 (0.21) | −0.68 (0.21) | −0.62 (0.23) | −0.68 (0.22) | −0.02 (−0.04, 0.006) |
Functional status, healthy utility, anxiety, well-being, quality of life, treatment satisfaction and relational empathy
Participants in the intervention group reported significantly higher levels of SF-36 physical functioning, SF-36 change in health, health utility (EQ-5D) and satisfaction with diabetes services than those in the comparison group (Table
5). There was no intervention effect on the remaining SF-36 measures, state anxiety, diabetes-specific and general well-being, diabetes-related quality of life, diabetes treatment satisfaction or relational empathy.
Table 5
Functional status, health utility, anxiety, quality of life, well-being and satisfaction with treatment at 1 year by study group and between-group differences in the ADDITION-Plus trial
SF-36 |
Physical functioning | 73.3 (27.8) | 79.2 (22.5) | 5.89 (1.24, 10.85) |
Role limitation, physical | 71.7 (40.2) | 76.0 (35.8) | 4.32 (−3.06, 11.29) |
Role limitation, emotional | 84.4 (32.2) | 80.7 (34.2) | −3.69 (−9.98, 1.99) |
Social functioning | 83.6 (25.3) | 85.1 (23.9) | 1.51 (−2.93, 6.02) |
Mental health | 76.3 (19.4) | 76.5 (17.3) | 0.15 (−3.25, 3.32) |
Energy/vitality | 56.5 (24.0) | 59.4 (20.8) | 2.97 (−1.11, 7.21) |
Pain | 71.6 (27.3) | 73.1 (25.2) | 1.50 (−3.28, 6.37) |
General health perception | 59.7 (23.4) | 61.2 (20.6) | 1.46 (−2.98, 5.51) |
Change in health | 55.4 (20.9) | 64.1 (22.7) | 8.72 (4.57, 12.74) |
Health utility |
Self-reported general health (1 to 5) | 2.94 (0.92) | 3.11 (0.87) | 0.19 (0.07, 0.31)c
|
EQ-5D (−0.3 to 1.0) | 0.81 (0.26) | 0.84 (0.20) | 0.03 (0.003, 0.06)c
|
Anxiety |
Spielberger State Anxiety (20 to 80) | 30.5 (11.0) | 29.6 (9.6) | −0.85 (−2.56, 0.85)c
|
Quality of life and well-being |
Quality of life (−9 to 9) | 0.96 (1.28) | 0.79 (1.05) | −0.17 (−0.38, 0.06) |
Diabetes-specific well-being (0 to 36) | 28.2 (6.6) | 28.8 (6.3) | 0.61 (−0.70, 1.76) |
General well-being (0 to 36) | 26.4 (7.2) | 26.9 (6.5) | 0.47 (−0.80, 1.81) |
Satisfaction with treatment, services and empathy |
Diabetes treatment satisfaction (0 to 36) | 30.0 (5.8) | 30.6 (5.3) | 0.59 (−0.41, 1.72) |
General practitioner CARE measure (10 to 50) | 39.1 (10.2) | 40.3 (9.5) | 1.23 (−0.64, 3.17) |
Nurse CARE measure (10 to 50) | 39.8 (9.8) | 40.9 (9.1) | 1.14 (−0.78, 2.89) |
Satisfaction with diabetes services (1 to 4) | 3.43 (0.79) | 3.68 (0.56) | 0.25 (0.13, 0.38) |
Beliefs about behavioural intentions, illness perceptions and habit
Behavioural intentions were higher in the intervention than the comparison group at 1 year, achieving statistical significance for physical activity and medication adherence (Table
6). Illness perceptions, perceived behavioural control and behavioural beliefs were similar in both groups at baseline and 1 year. In addition, there were no differences between groups in the strength of habit and diabetes knowledge levels at 1 year.
Table 6
Baseline and follow-up behavioural beliefs, illness perceptions, strength of habit and diabetes knowledge by study group and between-group differences in the ADDITION-Plus trial
Intention physical activity (1 to 5) | 3.72 (0.83) | 3.48 (0.79) | 3.78 (0.74) | 3.64 (0.81) | 0.14 (0.007, 0.27) |
Intention diet (1 to 5) | 3.71 (0.79) | 3.39 (0.84) | 3.75 (0.76) | 3.51 (0.81) | 0.11 (−0.03, 0.25) |
Intention medication adherence (1 to 5) | 4.45 (0.56) | 4.47 (0.60) | 4.40 (0.67) | 4.57 (0.58) | 0.12 (0.01, 0.23) |
Intention smoking (1 to 5) | 3.16 (1.11) | 3.12 (1.06) | 3.20 (0.96) | 3.20 (1.11) | 0.003 (−0.32, 0.33) |
Illness perception consequences (1 to 5) | 2.90 (0.65) | 2.88 (0.69) | 2.89 (0.64) | 2.95 (0.66) | 0.08 (−0.03, 0.18) |
Illness perception treatment control (1 to 5) | 3.80 (0.52) | 3.67 (0.55) | 3.75 (0.48) | 3.72 (0.52) | 0.08 (−0.01, 0.16) |
Perceived behavioural control physical activity (1 to 5) | 3.72 (0.91) | 3.51 (0.90) | 3.82 (0.79) | 3.67 (0.88) | 0.12 (−0.03, 0.26) |
Perceived behavioural control diet (1 to 5) | 3.75 (0.83) | 3.58 (0.85) | 3.70 (0.89) | 3.67 (0.87) | 0.11 (−0.03, 0.26) |
Perceived behavioural control medication (1 to 5) | 4.49 (0.56) | 4.47 (0.56) | 4.47 (0.63) | 4.56 (0.58) | 0.10 (−0.002, 0.20) |
Perceived behavioural control smoking (1 to 5) | 2.70 (0.97) | 2.90 (0.79) | 2.79 (1.01) | 2.91 (1.07) | −0.07 (−0.44, 0.30) |
Behavioural beliefs physical activity (1 to 5) | 4.01 (0.75) | 3.92 (0.64) | 3.98 (0.62) | 3.90 (0.72) | −0.002 (−0.11, 0.11) |
Behavioural beliefs diet (1 to 5) | 3.83 (0.75) | 3.75 (0.75) | 3.90 (0.68) | 3.81 (0.73) | 0.02 (−0.10, 0.14) |
Perceived effectiveness of lifestyle change (1 to 5) | 3.95 (0.72) | 3.82 (0.76) | 3.91 (0.65) | 3.84 (0.71) | 0.05 (−0.08, 0.18) |
Strength of PA habit change reported at 1 year (1 to 5) | – | 3.27 (0.72) | – | 3.41 (0.71) | 0.14 (−0.05, 0.32) |
Strength of diet habit change reported at 1 year (1 to 5) | – | 3.66 (0.55) | – | 3.64 (0.61) | −0.02 (−0.15, 0.12) |
Diabetes knowledge (self-administered questionnaire) (0 to 47) | – | 24.8 (9.18) | – | 25.8 (8.53) | 0.92 (−0.72, 2.57) |
In total, 93% of participants attended the introductory and initial three core-intervention sessions. Intervention group participants reported feeling confident in using the skills they had been taught (mean [SD] score 7.9 [1.7] on a scale of 0 to 10). Self-reported use of skills to increase physical activity and to eat a lower-fat diet was relatively high, ranging from 62% of participants who reported using prompts or reminders to 88% who reported setting achievable goals. Fewer participants reported using these skills to enhance medication adherence, ranging from 50% who reported that they had prepared for setbacks to 68% setting achievable goals. Skills use was lowest among those participants who were trying to stop smoking, with 26% recording or monitoring their progress and 45% reporting that they had set achievable goals. Intervention participants rated their facilitators highly with a mean response of 44 (SD 6.5, on a scale of 10–50).
Per protocol, subgroup and sensitivity analyses
Per protocol analyses of the primary outcome data replicated our main results, except for the plasma vitamin C level for which the increase over 12 months was slightly greater in the comparison than in the intervention group (p = 0.04). Our conclusions were unaffected by the sensitivity analysis for missing data. Similarly, there was no evidence that intervention effects on the primary outcomes differed between participants with screen-detected and recently diagnosed diabetes.
Discussion
For patients with recently diagnosed diabetes offered intensive treatment in primary care the additional input of a facilitator from outside the practice delivering a theory-based multi-behaviour intervention was not associated with significant improvements in objectively measured health behaviours. There was no difference between trial groups in change from baseline to 1 year in cardiovascular risk factors or self-reported health behaviours. The intervention group reported higher levels of SF-36 physical functioning as well as SF-36 change in health status, health utility and satisfaction with diabetes services at 1 year, and greater changes in diet and activity over the year compared with the comparison group. However, there was no intervention effect on the remaining SF-36 measures, state anxiety, diabetes-specific and general well-being, diabetes-related quality of life, diabetes treatment satisfaction or relational empathy. We found no evidence to support this external behavioural facilitator model of care where the primary care team delivers a well-organised and intensive treatment service.
Strengths and limitations
The study was carried out in primary care settings where most of the care of individuals with recently diagnosed diabetes takes place in the UK. General practice registers typically cover 99% of all residents living in England [
41], and nearly half of the practices approached agreed to take part. Generalisability to more deprived settings with greater ethnic diversity may be limited in light of the non-random recruitment of general practices from a single geographical region.
Internal validity was strong; participants were individually randomised and groups were well matched for baseline characteristics. Participant retention at 1 year was similarly high in both trial groups. We used objective measurement of four key behaviours affecting CVD risk, as well as measuring self-reported behaviour, functional status and well-being. The apparent effect on self-reported change in behaviours over time highlights the need for caution in interpreting the results of trials of behavioural interventions that rely on subjective measures. Clinically important outcomes were measured using standardised equipment and protocols, with trained staff unaware of study group allocation.
The intervention was based on theory and evidence from psychology to support change in behaviour [
42], and included a patient-centred approach to facilitating behaviour change, which has been shown to be more effective than didactic interventions in improving CVD risk factors [
43,
44]. Quality-assured delivery was enabled by training, ongoing supervision and protocols. The carefully characterised intervention and the objective measurement of health behaviours allowed us to isolate potential effects of the behavioural intervention from other aspects of intensive general practice care.
Plasma drug and cotinine levels were available only for a subset of participants and the timing of blood samples following ingestion of tablets and other factors affecting plasma drug levels were not standardised, which will have reduced the precision of estimates. However, these issues did not differ by study group and while the measure of adherence was less precise, it was less prone to bias than self-report measures. Objective measures of physical activity, smoking and medication adherence at baseline would have improved precision and enabled us to assess change over time. However, such detailed measurement might increase the salience and influence the behaviour of participants in both groups [
45]. This is likely to be more relevant to physical activity than to the other health behaviours assessed via blood samples.
Understanding the results
There may have been limited scope for additional benefit among ADDITION-Plus patients, who were already receiving intensive treatment, including theory-based educational materials and lifestyle advice on all the target behaviours by the primary care team. In addition, there were improvements from baseline in plasma vitamin C levels, self-reported diet and physical activity and cardiovascular risk factors in both study groups, further limiting potential change. The absence of an intervention effect on health behaviours was unlikely to be due to failure to deliver the programme. Attendance at intervention sessions, self-reported use of skills to improve lifestyle behaviours and levels of satisfaction with the programme were all high. Facilitators met monthly to discuss intervention delivery and listened to tape recordings of their sessions. They also received ongoing supervision and support from a clinical psychologist. The intervention was associated with stronger intentions to change physical activity and medication adherence at follow-up. We targeted mediators of behaviour change and included behaviour change techniques from a range of theories. However, the evidence that any of the commonly used theories predict changes in objectively assessed health behaviours is limited. Behaviour change might be enhanced by focusing on fewer behaviours and being more directive in selecting which ones to focus on. Targeting dietary change and physical activity sequentially might be less effective than targeting them simultaneously, but more evidence is needed [
46]. Increasing the intensity of the training or of intervention delivery could have enhanced the opportunity to change behaviour, but may not be feasible in routine practice. Facilitator-led care focusing on behaviour change might add value in settings where primary care based intensive treatment is not feasible or effective.
We recorded moderate effects of the intervention on measures of self-reported health status, health utility and physical function. These positive effects occurred independently of any change in objectively measured health behaviours, suggesting a mechanism independent of behaviour change. Other trials have also shown that interventions can improve patient-reported outcomes such as well-being but not behaviour or clinical endpoints [
33,
47]. It is not clear whether the improvements were related to the supportive alliances formed with lifestyle facilitators or whether the effect was mediated by a feeling of false reassurance from participating in the intervention [
48]. Regardless of the mechanism, self-reported health is an independent predictor of mortality [
49]. These improvements warrant further examination, particularly if they persist over the long term when intervention support is withdrawn and can be achieved with a less intensive intervention. Five-year follow-up of the trial cohort is planned.
Recent attempts to promote behaviour change in individuals soon after the diagnosis of diabetes have had mixed effects. In the Diabetes Education and Self-Management for Ongoing and Newly Diagnosed Diabetes (DESMOND) trial (ISRCTN17844016), 824 newly diagnosed patients were cluster randomised to receive either a 6 h structured group-education programme focused on behaviour change or usual care (comparison group) [
50]. The DESMOND trial participants had a mean age of 60 years, included more men than women (55%), had a mean BMI of approximately 32 kg/m
2 and were, therefore, broadly similar to ADDITION-Plus participants. The intervention was based on similar theories of learning used in the ADDITION-Plus trial and focused on lifestyle factors such as food choice and physical activity. Compared with the control group, the intervention group achieved greater improvements in weight loss and smoking cessation and positive improvements in belief about illness, but no difference in HbA
1c levels after 1 year. Self-reported physical activity levels were higher in the intervention than in the comparison group at all time points, but were not significantly different at 1 year. There was no objective measurement of behaviour change in this trial cohort and it was difficult to elucidate exactly which components of the intervention were associated with the observed improvements. Further, the DESMOND control group was different from our comparison group, where individuals were already receiving intensive treatment for diabetes.
In the Early ACTID trial, 593 recently diagnosed patients with a mean age of 60 years were randomised to receive usual care (control group), an intensive diet intervention (6.5 h of individual counselling by a dietitian/nurse over 1 year) or an intensive diet intervention plus a pedometer-based activity programme [
7]. After 12 months, there were significant improvements in glycaemic control, insulin resistance and body weight in both intervention groups compared with the control group; however, the addition of the activity intervention conferred no extra benefit. Accelerometry data indicated that individuals in the diet and activity group increased their physical activity significantly more than those in the other two groups. However, the lack of measurement of dietary change or any other health behaviour again makes it difficult to explain the beneficial effects observed in this trial. Other studies examining behavioural change in type 2 diabetes patients tend to be small, of shorter duration and to focus on individuals later in the disease trajectory. No published trial to date captures objective measurement of four key health behaviours in recently diagnosed patients.
Acknowledgements
We are grateful to all participants, lifestyle facilitators, practice nurses and family physicians for taking part in the ADDITION-Plus trial: Arbury Road Surgery, Ashwell Surgery, Birchwood Surgery, Bottisham Medical Practice, Brookfields/Cherry Hinton, Buckden Surgery, Clarkson Surgery, Cornerstone Practice, Cornford House Surgery, Cottenham Surgery, Dr Eaton & Partners (Saffron Walden), George Clare Surgery, Great Staughton Surgery, Haddenham Surgery, Hilton House Surgery, Lensfield Road Surgery, Manea Surgery, Milton Surgery, New Roysia Surgery, Orchard House Surgery, Orton Medical Practice, Parkhall Road Surgery, Park Medical Centre, Petersfield Medical Practice, Riverside Practice, Rookery Medical Centre, Rosalind Franklin House, South Street Surgery, St Mary’s Surgery, Thaxted Surgery, The Old Exchange, The Spinney Surgery, The Surgery (Over) and Woolpit Surgery. We are grateful to the independent endpoint committee (N. Stott [Chair; University of Cardiff, UK], J. Weinman [King’s College, London, UK], R. Himsworth [University of Cambridge, UK] and P. Little [University of Southampton, UK]). We thank D. Hughes (University of Bangor, Wales) for his help with examining the medication adherence data. We thank all ADDITION-Plus study team members at The Primary Care Unit, University of Cambridge and the Medical Research Council Epidemiology Unit, Cambridge, UK, who jointly coordinated the baseline and 1 year follow-up phases of the study. We thank the Cambridge University Hospitals NHS Foundation Trust Department of Clinical Biochemistry and the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre, Core Biochemical Assay Laboratory for carrying out the biochemical assays, and the following groups within the MRC Epidemiology Unit: data management (A. Dickinson), information technology (I. Morrison), technical (M. Sims), physical activity (K. Westgate, S. Mayle) and field epidemiology (P. Roberts, K. Mwanza, J. Grant, F. Whittle and J. Sylvester). Permission to use the Diabetes Treatment Satisfaction Questionnaire was granted by C. Bradley, Health Psychology Research, Royal Holloway University of London, Surrey, UK.