The study was designed as a two-armed cluster-randomized controlled trial. At the beginning of the study, around 2.000 Bavarian general practitioners (GPs) received a fax by the Bavarian Association of General Practitioners with information about the research project. All interested GPs were sequentially registered for randomization. After giving written consent, the participating practices were randomized either to the interventional or the control arm. The sequence of randomization (allocation 1:1) was provided by a methodologist, who did not participate in the execution of the study, via the program Randomizer (http://www.randomizer.org). Randomization was concealed by using sequentially numbered, opaque sealed envelopes hold by the study coordinator. Before starting recruitment of patients, physicians and practice nurses received detailed instructions by the research team on the study process (both intervention and control group) and on the coaching program (only intervention group).
Physicians assigned to the control arm were asked to change nothing in their usual way of counselling and to treat participants in the same manner as if they would have been non-participants. There was no structured documentation of the care provided.
The patients recruited by intervention practices received free access to the web-based coaching program. The patients of practices participating in the control arm were advised by the GPs in their individual way of usual care to reduce weight.
The study was approved by the Medical Ethics Committee of the Technical University of Munich on 19 April 2011 and was in accordance with ethical standards for human experimentation established by the Declaration of Helsinki. All participants gave written informed consent. A data and safety monitoring board was established before the beginning of the study. The study was registered on the German Register for Clinical Trials (http://apps.who.int/trialsearch/; registration number DRKS00003067).
Participants and procedures
Participating physicians were general practitioners in Bavaria, Germany. The GPs were requested to recruit overweight individuals of whom a weight reduction was recommendable. Individuals with a BMI ≥ 25 were potentially eligible. Exclusion criteria were age younger than 18 year, insufficient German language skills, and lack of internet access. Further exclusion criteria were BMI < 25, Type-1-diabetes, hypothyroidism, pregnancy, breast feeding, addiction to drugs or alcohol, consuming and immune deficit disorders, heavy mental illnesses, osteoporosis, renal insufficiency, heart failure, coronary heart disease, eating disorders, cirrhosis of the liver, acute infections, other heavy metabolic illnesses (e.g. gouts).
After decision of the GP that the participation of a patient was recommendable for enrolment, an information form was given and discussed and a participation form had to be signed. At the same time the baseline data acquisition took place. All participants were asked to fill in a standardized questionnaire together with the GP. Baseline data of weight and waist circumference were measured in general practice; eating behaviour and physical activity were documented at the same time. Participants of the intervention group received a free web-code. The physician filled in a form together with the patient with detailed information about diabetes mellitus or hypertension (if necessary), dietary advices (like low cholesterol diet) and suggested physical activity. This form and the web-code are used by the patient for specification during the registration process of the internet program.
Physicians of both groups were requested to document the anthropometric measures from the participants with their existing practice equipment. The physicians were advised to measure the weight in underwear without shoes and to measure the waist circumference corresponding to the standardised definition (measured with a tape around the abdomen located marginally above the upper hip bone). A follow-up investigation with the same measurements and documentation was performed in the general practices twelve weeks after inclusion.
Physicians in the intervention group received € 50.- per participant for time and effort. Physicians in the control group received € 25.-. Participants in the intervention group received free access to the HausMed weight reduction program which usually costs € 79.-. Participants in the control group received € 10.- as an incentive to come into practice for follow-up investigation after twelve weeks. Safety monitoring in the intervention arm was guaranteed by a check of the health status four weeks after beginning of the study.
Anamnestic and health data were documented in a structured form including information about co-morbidities and physical activity advises from the GP. The patient received a copy of this form in order to use the health data and advises for inscribing via Internet into the coaching program (HausMed eHealth Services GmbH, Berlin; Germany; http://www.hausmed.de; indexed in Internet Archive) at home. A specific website was installed for the participants to allow a login without charge. After completion of a pre-assessment, the program generated an individual coaching based on the recommendations of the physicians, the physical characteristics and the everyday behaviour of the participants.
The coaching program is based on principals of the cognitive behavioural therapy – e.g. education, realistic goal-setting and individual resources – and in particular on the behavioural change theory targeted to reduce and maintain weight by using inexpensive Internet and mobile technologies in combination with existing health care resources of GPs. The content of the coaching program aims at achieving a lasting change of behaviour patterns with the help of individualized education, motivation, exercise guidance, daily SMS reminders, self-monitoring via Internet and, finally, through an active monitoring and approximately 3 telephone calls during the 12 weeks by the GPs or their respective staff.
The framework of the program is based on the idea by Prof. Dr. Pudel, Institute for Nutrition and Psychology Research Department at the University of Göttingen [12, 13]. A weight loss plan including individual energy requirements supports each patient during the 12 weeks and assures an adequate nutrition including nutrients such as proteins, carbons and fat. The given dietary recommendations are based on current nutritional guidelines (German Nutrition Society - DGE). Additionally, the program was conceptualised for the nutritional needs of diabetics and hypertensive patients.
The coaching program is subdivided into 12 different constitutive modules. Each module is performed for one week and contains a particular exercise, which is supported by a corresponding daily SMS reminder. The goals of the particular exercises are:
to introduce a structured diet plan
to prevent fear for changing eating habits
to enhance physical activity in regard to the individual condition
to achieve a flexible control of eating behaviour
to learn a conscious individualized food and fluid intake
to motivate for physical activity
to consume five portions of fruits and vegetables a day
to understand the effect of insulin and to control blood sugar
to understand the effect of salt respective hypertension
to prevent failures and develop coping strategies
to achieve a conscious handling with fatty acids
to relief active stress
to objective realistic goals and to frame sub-goals
to summarize achieved goals and to motivate to continue
The reminder has an adapted content to obtain the motivation and to impart daily tips. The coaching program also offers a variety of printing material (diet plans, recipes, questionnaires, information, self-agreements etc.) which is connected to the respective exercise and includes interactive buttons, video clips and learning progress quizzes to examine the learning success. At the end of each week participants are asked to give feedback via the internet concerning their condition and level of motivation and whether or not they did their weekly task. Diary entries for weight and waist circumferences are offered as well. Participants can also communicate among themselves through a forum or ask a HausMed team member should they have any questions. The active monitoring (or rather supervising) of the entire twelve-week coaching course is carried out through a separate login account in a particularly secured physician area (weight, waist circumference, motivation, condition and status of the module exercise). In addition to that, three specified telephone calls from the GP or a qualified practice nurse (week 1, 5 and 12) are implemented to primarily motivate and support the participants. If either a participant’s motivation or condition declines notably within the weekly feedback at any point during the coaching period or the module exercise is not completed, additional counselling from the GP or practice nurse is made over the telephone. There is no limitation to the frequency of website use but participants were given a goal of using the website at least once a week and GPs are advised to log in into the program twice a week. This trial was the first evaluation of this intervention.
The primary outcome measure was weight loss in kg twelve weeks after inclusion into the study. Weight was measured at baseline and after 12 weeks. Secondary outcome measures were difference in waist circumference, BMI, eating behaviour and physical activity. The waist circumference was measured at baseline and after 12 weeks. The evaluation of the self estimated eating behaviour (range from 1–5), conscious eating pattern (range from 0–2), frequent cooking/ cooked meals (range from 0–2) and physical activity (range from 1–4) was conducted at baseline and after 12 weeks. A higher number on the scale refers to a more even or more conscious eating behaviour, more frequent cooking/ cooked meals or more frequent physical activity.
Sample size calculation was performed with G * Power 3 correcting for the cluster design (intra-cluster correlation coefficient = 0.05, average cluster size = 3) for two-sided testing (α = 5% and a power of 80%). Using these assumptions the calculated total sample size for primary outcome weight loss was 142 participants. Taking expected attrition into account we aimed at recruiting a total of 180 participants in about 60 general practices.
Baseline data are presented descriptively. Group differences were calculated for all participants whose weight was available at baseline and follow-up (completer collective). Sensitivity analysis was performed by an intent-to-treat analysis assuming that participants with missing values had no weight change at all. The strongly variable cluster size caused major numerical problems in the linear mixed model analysis. As it was not possible to adjust for intra cluster correlations properly and because of the high number of practices with only one patient (12 practices), it was decided to perform the main analysis using Student’s t-test without accounting for the clusters. For the outcomes weight loss, changes in BMI and waist circumference we also performed secondary analyses based on generalized estimating equations with adjustment for baseline values, age, diets and occupational status. These analyses were performed as sensitivity analyses and take account of practices as patient clusters. All analyses were performed using SPSS version 19.0 (Inc., Chicago, IL).