Cost-effectiveness of the SLIMMER diabetes prevention intervention in Dutch primary health care: economic evaluation from a randomised controlled trial.

BACKGROUND: Although evidence is accumulating that lifestyle modification may be cost-effective in patients with prediabetes, information is limited on the cost-effectiveness of interventions implemented in public health and primary health care settings. Evidence from well-conducted pragmatic trials is needed to gain insight into the realistic cost-effectiveness of diabetes prevention interventions in real-world settings. The aim of this study is to assess the cost-effectiveness of the SLIMMER lifestyle intervention targeted at patients at high risk of developing type 2 diabetes compared with usual health care in a primary care setting in the Netherlands. METHODS: Three hundred and sixteen high-risk subjects were randomly assigned to the SLIMMER lifestyle intervention or to usual health care. Costs and outcome assessments were performed at the end of the intervention (12 months) and six months thereafter (18 months). Costs were assessed from a societal perspective. Patients completed questionnaires to assess health care utilisation, participant out-of-pocket costs, and productivity losses. Quality Adjusted Life Years (QALY) were calculated based on the SF-36 questionnaire. Cost-effectiveness planes and acceptability curves were generated using bootstrap analyses. RESULTS: The cost-effectiveness analysis showed that the incremental costs of the SLIMMER lifestyle intervention were €547 and that the incremental effect was 0.02 QALY, resulting in an incremental cost-effectiveness ratio (ICER) of €28,094/QALY. When cost-effectiveness was calculated from a health care perspective, the ICER decreased to €13,605/QALY, with a moderate probability of being cost-effective (56% at a willingness to pay, WTP, of €20,000/QALY and 81% at a WTP of €80,000/QALY). CONCLUSIONS: The SLIMMER lifestyle intervention to prevent type 2 diabetes had a low to moderate probability of being cost-effective, depending on the perspective taken. TRIAL REGISTRATION: The SLIMMER study is retrospectively registered with ClinicalTrials.gov (Identifier NCT02094911) since March 19, 2014.

Process evaluation of a randomised controlled trial of a diabetes prevention intervention in Dutch primary health care: the SLIMMER study.

OBJECTIVE: To investigate (i) how the SLIMMER intervention was delivered and received in Dutch primary health care and (ii) how this could explain intervention effectiveness. DESIGN: A randomised controlled trial was conducted and subjects were randomly allocated to the intervention (10-month combined dietary and physical activity intervention) or the control group. A process evaluation including quantitative and qualitative methods was conducted. Data on process indicators (recruitment, reach, dose received, acceptability, implementation integrity and applicability) were collected via semi-structured interviews with health-care professionals (n 45) and intervention participant questionnaires (n 155). SETTING: SLIMMER was implemented in Dutch primary health care in twenty-five general practices, eleven dietitians, nine physiotherapist practices and fifteen sports clubs. SUBJECTS: Subjects at increased risk of developing type 2 diabetes were included. RESULTS: It was possible to recruit the intended high-risk population (response rate 54 %) and the SLIMMER intervention was very well received by both participants and health-care professionals (mean acceptability rating of 82 and 80, respectively). The intervention programme was to a large extent implemented as planned and was applicable in Dutch primary health care. Higher dose received and participant acceptability were related to improved health outcomes and dietary behaviour, but not to physical activity behaviour. CONCLUSIONS: The present study showed that it is feasible to implement a diabetes prevention intervention in Dutch primary health care. Higher dose received and participant acceptability were associated with improved health outcomes and dietary behaviour. Using an extensive process evaluation plan to gain insight into how an intervention is delivered and received is a valuable way of identifying intervention components that contribute to implementation integrity and effective prevention of type 2 diabetes in primary health care.

SLIMMER: a randomised controlled trial of diabetes prevention in Dutch primary health care: design and methods for process, effect, and economic evaluation.

BACKGROUND: Implementation of interventions in real-life settings requires a comprehensive evaluation approach. The aim of this article is to describe the evaluation design of the SLIMMER diabetes prevention intervention in a Dutch real-life setting. METHODS/DESIGN: The SLIMMER study is a randomised, controlled intervention study including subjects aged 40 through 70 years with impaired fasting glucose or high risk of diabetes. The 10-month SLIMMER intervention involves a dietary and physical activity intervention, including case management and a maintenance programme. The control group receives usual health care and written information about a healthy lifestyle. A logic model of change is composed to link intervention activities with intervention outcomes in a logical order. Primary outcome is fasting insulin. Measurements are performed at baseline and after 12 and 18 months and cover quality of life, cardio-metabolic risk factors (e.g. glucose tolerance, serum lipids, body fatness, and blood pressure), eating and physical activity behaviour, and behavioural determinants. A process evaluation gives insight in how the intervention was delivered and received by participants and health care professionals. The economic evaluation consists of a cost-effectiveness analysis and a cost-utility analysis. Costs are assessed from both a societal and health care perspective. DISCUSSION: This study is expected to provide insight in the effectiveness, including its cost-effectiveness, and delivery of the SLIMMER diabetes prevention intervention conducted in Dutch primary health care. Results of this study provide valuable information for primary health care professionals, researchers, and policy makers. TRIAL REGISTRATION: The SLIMMER study is registered with ClinicalTrials.gov (NCT02094911) since March 19, 2014.

Using the intervention mapping protocol to develop a maintenance programme for the SLIMMER diabetes prevention intervention.

BACKGROUND: Although lifestyle interventions have shown to be effective in reducing the risk for type 2 diabetes mellitus, maintenance of achieved results is difficult, as participants often experience relapse after the intervention has ended. This paper describes the systematic development of a maintenance programme for the extensive SLIMMER intervention, an existing diabetes prevention intervention for high-risk individuals, implemented in a real-life setting in the Netherlands. METHODS: The maintenance programme was developed using the Intervention Mapping protocol. Programme development was informed by a literature study supplemented by various focus group discussions and feedback from implementers of the extensive SLIMMER intervention. RESULTS: The maintenance programme was designed to sustain a healthy diet and physical activity pattern by targeting knowledge, attitudes, subjective norms and perceived behavioural control of the SLIMMER participants. Practical applications were clustered into nine programme components, including sports clinics at local sports clubs, a concluding meeting with the physiotherapist and dietician, and a return session with the physiotherapist, dietician and physical activity group. Manuals were developed for the implementers and included a detailed time table and step-by-step instructions on how to implement the maintenance programme. CONCLUSIONS: The Intervention Mapping protocol provided a useful framework to systematically plan a maintenance programme for the extensive SLIMMER intervention. The study showed that planning a maintenance programme can build on existing implementation structures of the extensive programme. Future research is needed to determine to what extent the maintenance programme contributes to sustained effects in participants of lifestyle interventions.

Adapting the SLIM diabetes prevention intervention to a Dutch real-life setting: joint decision making by science and practice.

BACKGROUND: Although many evidence-based diabetes prevention interventions exist, they are not easily applicable in real-life settings. Moreover, there is a lack of examples which describe the adaptation process of these interventions to practice. In this paper we present an example of such an adaptation. We adapted the SLIM (Study on Lifestyle intervention and Impaired glucose tolerance Maastricht) diabetes prevention intervention to a Dutch real-life setting, in a joint decision making process of intervention developers and local health care professionals. METHODS: We used 3 adaptation steps in accordance with current adaptation frameworks. In the first step, the elements of the SLIM intervention were identified. In the second step, these elements were judged for their applicability in a real-life setting. In the third step, adaptations were proposed and discussed for those elements which were deemed not applicable. Participants invited for this process included intervention developers and local health care professionals (n=19). RESULTS: In the first adaptation step, a total of 22 intervention elements were identified. In the second step, 12 of these 22 intervention elements were judged as inapplicable. In the third step, a consensus was achieved for the adaptations of all 12 elements. The adapted elements were in the following categories: target population, techniques, intensity, delivery mode, materials, organisational structure, and political and financial conditions. The adaptations either lay in changing the SLIM protocol (6 elements) or the real-life working procedures (1 element), or a combination of both (4 elements). CONCLUSIONS: The positive result of this study is that a consensus was achieved within a relatively short time period (nine months) between the developers of the SLIM intervention and local health care professionals on the adaptations needed to make SLIM applicable in a Dutch real-life setting. Our example shows that it is possible to combine the perspectives of scientists and practitioners, and to find a balance between evidence-base and applicability concerns.

Translating the SLIM diabetes prevention intervention into SLIMMER: implications for the Dutch primary health care.

All over the world, prevalence and incidence rates of type 2 diabetes mellitus are rising rapidly. Several trials have demonstrated that prevention by lifestyle intervention is (cost-) effective. This calls for translation of these trials to primary health care. This article gives an overview of the translation of the SLIM diabetes prevention intervention to a Dutch real-life setting and discusses the role of primary health care in implementing lifestyle intervention programmes. Currently, a 1-year pilot study, consisting of a dietary and physical activity part, performed by three GPs, three practice nurses, three dieticians and four physiotherapists is being conducted. The process of translating the SLIM lifestyle intervention to regular primary health care is measured by means of the process indicators: reach, acceptability, implementation integrity, applicability and key factors for success and failure of the intervention. Data will be derived from programme records, observations, focus groups and interviews. Based on these results, our programme will be adjusted to fit the role conception of the professionals and the organization structure in which they work.

Is the success of the SLIMMER diabetes prevention intervention modified by socioeconomic status? A randomised controlled trial.

AIM: To explore the role of socioeconomic status (SES) in participation, programme attendance, programme acceptability, adherence to lifestyle guidelines, drop-out, and effectiveness in the SLIMMER diabetes prevention intervention. METHODS: SLIMMER was a randomised controlled intervention, carried out in a real-world setting, targeting 40- to 70-year-old adults at increased risk of developing type 2 diabetes (n=316). The intervention group participated in a 10-month combined dietary and physical activity programme. Measurements were carried out at baseline, 12months, and 18months. Effectiveness was determined for fasting insulin, HbA1c, weight, BMI, waist circumference, and waist-to-height-ratio. Differences between the low SES (no, primary, or lower secondary school) and higher SES group were tested using logistic regression and ANCOVA. RESULTS: Fifty-two percent of the SLIMMER participants had a low SES. No differences in participation were observed between the low and higher SES group. The most important reason for non-participation in the low SES group was 'lack of interest' (32%), whereas in the higher SES group this was 'I already exercise enough' (31%). Attendance, acceptability, adherence, drop-out, and effectiveness after 12months were similar in the low and higher SES group. After 18months, the low SES group seemed to maintain slightly better effects for fasting insulin, HbA1c, and waist circumference. CONCLUSIONS: The current study showed that participation, attendance, acceptability, adherence, drop-out, and effectiveness of the SLIMMER intervention were in general not modified by socioeconomic status. The SLIMMER intervention can contribute to health promotion for individuals in both low and higher socioeconomic groups.

Effectiveness of a Dutch community-based alcohol intervention: Changes in alcohol use of adolescents after 1 and 5 years.

BACKGROUND: Underage alcohol drinking is a severe public health problem. The aim of this study was to evaluate the short- and long-term effects of a Dutch community-based alcohol intervention on alcohol use of adolescents in the second and fourth grade of high school. METHODS: The community intervention integrated health education, regulation, and enforcement in multiple settings, targeting adolescents as well as their environments. In order to evaluate effectiveness, a quasi-experimental pretest posttest design was used based on three independent cross-sectional surveys in 2003, 2007 and 2011, resulting in an analytical sample of approximately 5700 and 3100 adolescents in the intervention and reference region, respectively. For the main analyses, we compared the change in recent alcohol use and binge drinking in the intervention region with the reference region. Linear regression was used to obtain (adjusted) prevalence of alcohol use. RESULTS: During the study period, there was an overall decline in the prevalence of alcohol use. After 1 year of intervention, the decline was 11% (P<0.01) and 6% (P<0.01) stronger in the intervention region as compared to the reference region, for recent alcohol use and binge drinking respectively. This effect was restricted to the second grade and remained after 5 years of intervention. No clear subgroup effects or confounding were observed for ethnicity, gender or educational level. CONCLUSIONS: The Dutch community intervention appears to be effective on the short- and long-term in reducing the prevalence of recent alcohol use and binge drinking of (underage) adolescents in the second grade of high school.

Lifetime estrogen exposure versus age at menopause as mortality predictor.

OBJECTIVES: The aim of this study was to evaluate the relation between lifetime estrogen exposure and mortality and compare this with menopausal age as exposure variable. METHODS: We studied a cohort of 1462 naturally postmenopausal women, aged 37-77 at enrollment in the Belgian Interuniversity Research on Nutrition and Health study. After a follow-up time of 10 years, 181 women had died, of whom 76 of cardiovascular causes. Logistic regression analysis was used to investigate the relations between lifetime estrogen exposure (calculated as menopausal age minus menarcheal age) and death as well as the relations between age at menopause and death. RESULTS: The risk of mortality was lower in women with a longer lifetime estrogen exposure as well as in women with higher menopausal ages. For women with a lifetime estrogen exposure of >or=40 years the odds ratio of all-cause mortality was 0.58 (95% confidence interval (CI) 0.35-0.93) compared to women who had a lifetime estrogen exposure of

Feasibility and potential impact of the adapted SLIM diabetes prevention intervention in a Dutch real-life setting: the SLIMMER pilot study.

OBJECTIVE: Pilot-testing of the adapted Study on Lifestyle intervention and Impaired glucose tolerance Maastricht (SLIM) and to determine its feasibility and likelihood of achieving desired impact. METHODS: Pilot intervention study (a 10-month combined lifestyle intervention) using a one group pre-test post-test design with on-going process measures (i.e. reach, acceptability, implementation integrity, and applicability) and several health outcomes (e.g. body weight). RESULTS: In total, 31 subjects participated in the SLIMMER (SLIM iMplementation Experience Region Noord- en Oost-Gelderland) intervention. Participant weight loss was -3.5 kg (p=0.005). Both participants and health care professionals (i.e. practice nurses, dieticians, and physiotherapists) were satisfied with the intervention. The intervention was implemented as planned and appeared to be suitable for application in practice. Refinements have been identified and will be made prior to further implementation and evaluation. CONCLUSION: Implementation of the SLIMMER intervention is feasible in a Dutch real-life setting and it is likely to achieve desired impact. Practising and optimising the intervention creates local support for SLIMMER among stakeholders. PRACTICE IMPLICATIONS: Performing a pilot study on the basis of a structured approach is a meaningful step in the process of optimising the feasibility and potential impact of an evidence-based intervention in a real-life setting.

Intolerance to dietary biogenic amines: a review.

OBJECTIVE: To evaluate the scientific evidence for purported intolerance to dietary biogenic amines. DATA SOURCES: MEDLINE was searched for articles in the English language published between January 1966 and August 2001. The keyword biogenic amin* was combined with hypersens*, allerg*, intoler*, and adverse. Additionally, the keywords histamine, tyramine, and phenylethylamine were combined with headache, migraine, urticaria, oral challenge, and oral provocation. Articles were also selected from references in relevant literature. STUDY SELECTION: Only oral challenge studies in susceptible patients were considered. Studies with positive results (ie, studies in which an effect was reported) were only eligible when a randomized, double-blind, placebo-controlled design was used. Eligible positive result studies were further evaluated according to a number of scientific criteria. Studies with negative results (ie, studies in which no effect was reported) were examined for factors in their design or methods that could be responsible for a false-negative outcome. Results of methodologically weak or flawed studies were considered inconclusive. RESULTS: A total of 13 oral challenge studies (5 with positive results and 8 with negative results) were found. Three of them (all with positive results) were considered ineligible. By further evaluation of the 10 eligible studies, 6 were considered inconclusive. The 4 conclusive studies all reported negative results. One conclusive study showed no relation between biogenic amines in red wine and wine intolerance. Two conclusive studies found no effect of tyramine on migraine. One conclusive study demonstrated no relation between the amount of phenylethylamine in chocolate and headache attacks in individuals with headache. CONCLUSIONS: The current scientific literature shows no relation between the oral ingestion of biogenic amines and food intolerance reactions. There is therefore no scientific basis for dietary recommendations concerning biogenic amines in such patients.