The present study reported 3- and 5-year follow-up results from an observational study of an initial one-year combined inpatient-outpatient treatment of obese children and adolescents. Given the fact that obesity treatment has to focus on long-term weight reduction and maintenance rather than short-term weight loss, and given the limited number of studies reporting long-term results of obesity treatment, the present study addresses an important gap in current knowledge.
The strengths of the present study include the long follow-up duration of up to five years and a moderately large sample of 604 consecutive participants of a multidisciplinary treatment programme over 12 months.
However, before highlighting and discussing the main findings of the present study, a number of important limitations need to be pointed out. First of all, this follow-up study reports about the long-term effects of an uncontrolled study. Due to legal concerns regarding the indiscriminate access to standard treatment offered by a health insurance company, we were not able to establish a control group for the long observation period of 5 or even 3 years. However, in a previous report, we have ascertained that the short-term effects of this treatment approach over 6 months were significantly better in terms of development of body weight, health behaviour, and quality of life in the treated group as compared to untreated waiting list control group [52
Secondly, as in other long-term follow-up studies of obesity treatment, we have a considerable portion of subjects who were lost to follow-up. Total dropout rate was 36.6% after 3 years and 57.8% after 5 years. The reasons for nonparticipation in the follow-up assessments indicate that attrition is at least partially related to unsuccessful weight and behaviour change. Nevertheless, the follow-up rates in our study may be considered as somewhat satisfying compared to other studies in the field. In an observational follow-up study of different treatment programmes in Germany, loss to follow-up was already 58.6% one year after the end of treatment and 72.5% after initial inpatient treatment [65
]. In an attempt to compensate for our nevertheless large and presumably biased loss to follow-up, we consequently used an intention to treat analysis with baseline values imputed for missing values at follow-up which eventually handles dropouts as a “failure.” Thus, the estimates of treatment effects are considered conservative in the sense that true effects might be slightly better than our estimates.
In addition, several evaluated parameters were self-reports and therefore dependent on the self-perception and honesty of the participants and, hence, liable to bias. This particularly concerns the parameters eating behaviour, food intake, perceived self-competence, and quality of life. These limitations were, however, compensated for by an objective measurement of the quantitative parameter body weight, which reflects the actual physical state.
Moreover, quite a number of behavioural and psychosocial variables were subjected to an exploratory analysis without adjusting significance levels for multiple testing. While this probably increases the number of significant results for our study, these additional results only have an informative role, that is, to explore trends in associated behavioural and psychosocial changes. The primary parameters of interest in our study are the BMI-SDS and the description of the initiating and accompanying health-related behaviour.
Taking these limitations into account, a major finding of our study was that 3 years after the start of treatment, 34.3% of the children and adolescents documented a successful weight reduction of more than 0.2 BMI-SDS units, and five years after baseline, still 21.3% of participants show a successful reduction. It should be noted that these proportions are based on all 604 patients that originally were included in the study (intention to treat principle) and that dropouts are included with an assigned BMI-SDS reduction of 0. On average, there was a significant mean reduction of BMI-SDS by −0.20 ± 0.49 after 3 years and −0.15 ± 0.51 after 5 years. This is probably less than most patients, their families, and their therapists would hope and certainly leaves room for further improvement. Nevertheless, a reduction of BMI-SDS by 0.2 has been suggested as a criterion for successful weight reduction in children and adolescents [58
]. Thus, on an average, the patients maintain a successful weight reduction after 3 years even when a conservative intention to treat estimate is used as in the present study.
Five years after baseline, the weight reduction is further attenuated to 0.15 ± 0.51 BMI-SDS units. Nevertheless, it has been shown that a weight reduction of this magnitude is already associated with a decrease of hypertension [66
]. Hypertension in childhood may contribute to a higher risk for cardiovascular diseases in adulthood [67
], and therefore a reduction of hypertension as a result of weight reduction during a obesity treatment program is an important effect.
Most studies focusing on long-term outcomes of childhood obesity treatment did not publish their results in the form of BMI-SDS change, and rather they indicated changes in body weight in kg or BMI. However, some studies have also published BMI-SDS data. Reinehr and colleagues (2003) [68
] in a study in Germany compared the weight reduction of overweight children after one and two years, among three groups, that is, after the one-year outpatient training “Obeldicks,” after a single consultation session and in the group without treatment. After two years (the nearest to our 3-year-follow-up), the children who were trained in the outpatient treatment group showed significant reduction in BMI-SDS by −0.30 (−2.10 up to +0.46).
Another study from Italy [47
] described an even greater decrease of BMI-SDS by −0.44 ± 0.7 within 3 years, for children who had participated in a therapeutic education program. Yet the study only included overweight (not obese) children without any evident psychological problems. In addition, from that article, it was not clear whether the authors had used intention-to-treat analyses; it seems as if they reported a completer analysis, which of course yields more optimistic results.
In our study, successful weight reduction clearly showed age- and gender-specific differences. Generally, successful long-term weight reduction was considerably more frequent among girls than boys, and girls aged 12 years and older benefited more from the treatment program than younger girls. One reason for the lower success among younger patients could lie in the focus of improving self-control, which was an essential element of the therapy. Probably, the control of and responsibility for eating and exercise behaviour is more with the parents than with the children themselves. Thus, targeting the parents in the treatment for younger patients could be a useful way to improve treatment effects. Moreover, the gender differences found in the older children and adolescents suggest that more research is needed to understand how particularly boys can be supported in the change of eating and exercise behaviour.
In addition to weight reduction, a number of other significant improvements were observed. Concerning food intake, particularly the consumption of calorie-reduced beverages increased significantly and that of non-recommended foods decreased. Improvements were also seen in several aspects of perceived self-competence. However, positive changes in physical activity could not be maintained after the end of the therapy phase.
Furthermore, our study showed that successful weight reduction is associated with improvements of quality of life. Although the group of participants who reduced their weight successfully is decreasing over the observation period, after five years, those patients with successful weight reduction maintained a better quality of life than those who did not reduce their weight successfully.
Lower health-related quality of life has been associated with obesity in preschoolers already [16
]. Obesity has been shown to be a cause for teasing and bullying in children, and these in turn can contribute to the development of psychological consequences like a depression [23
]. Depressive symptoms themselves contribute to lower quality of life [69
], just as obesity itself too [16
]. Therefore, improvement of health-related quality of life is an important result beyond the mere weight reduction and associated health benefits.
In Germany, recently doubts were expressed about the effectiveness of childhood obesity treatment programs, let alone the associated cost-effectiveness, given the high costs of many treatment approaches, particularly of long-term treatment. The present study shows that a life-style oriented, multidisciplinary treatment approach can achieve considerable long-term weight reduction and change of relevant health behaviours, although both far from optimum. The effects of obesity treatment on improved quality of life in addition to direct health effects related to weight reduction are worthwhile to support children and adolescents in weight reduction.
Another important aspect of the present study is related to the combination of inpatient and outpatient treatment of obese children and adolescents. Due to the structure of the German Health Care System, currently two distinct types of treatments are offered to obese patients and their families. One option being a short-term inpatient treatment of less than 3 months duration, usually the duration is 6 weeks and the treatment takes place in a specialised hospital. Often, these hospitals are located far away from the residence of the patients. The other available option is an outpatient treatment programme, conducted near the home of the patients. The duration of such programmes are considerably longer, often one year, usually with weekly therapy sessions. Results from a national observation study showed that the intensive inpatient treatment results achieve better short-term weight reduction and behaviour change at the end of treatment when compared to long-term outpatient treatment programs [65
]. However, long-term results one year after the end of treatment are less clear, because follow-up assessments of these inpatient treatments resulted in an enormous lost-to-follow-up rate [65
]. Thus, the verified long-term rate of successful weight reduction has been considerably lower in these inpatient treatments than outpatient treatments. The average rate of verified successful weight reduction (BMI-SDS reduction more than 0.2) one year after the end of outpatient treatments appeared to be approximately 20% (intention to treat). In the present study, two years after the end of treatment, such successful weight reduction could be documented for 34% of all initial patients, and successful weight reduction was maintained over 4 years after the end of treatment for more than 20%. Thus, the combination of an initial intensive inpatient treatment followed by long-term outpatient treatments seems to combine the advantages of both approaches: substantial behaviour change during initial intensive therapy and better maintenance of changes during the transfer of behaviour changes in the everyday environment [51
Nevertheless, the sustainability of successful weight reduction could be still better. The extended support after the end of the treatment program could be one approach to achieve better sustainability. The internet with emails, virtual meetings in chat rooms, or interactive blogs could be a promising vehicle, especially since children and adolescents nowadays feel comfortable using the internet with all its possibilities. A recent systematic review concluded that interactive computer-based interventions are effective in supporting weight loss and weight maintenance [70
Another aspect that should be considered is the amount of exercise and intensity of family involvement in obesity treatment. A current review and meta-analysis showed that exercise and family involvement are important components of effective treatment programs [71
]. Family involvement improves the probability for children and adolescents to be successful in a weight reduction program. An interesting approach to enhance family involvement in physical activity was reported in a 6-month community-based program which showed remarkable postintervention effects [72
]. Children and parents received eighteen 2-hour education and exercise sessions, twice a week. This was followed by a 12-week free swimming pass for the family. Such posttreatment measure that motivates to more exercise—maybe combined with a monetary incentives—might be sensible and could enhance the sustainability of the effects of weight reduction programs.
Regarding treatment in our study, these aspects should be considered for further improvement. Family involvement is already part of the treatment approach but could probably be intensified. In addition, anecdotal reports from staff of the initial inpatient treatment pointed out that the children were often highly motivated to continue exercise. However, back home, it was apparently difficult to maintain this motivation and continue with higher levels of exercise. Thus, generating more opportunities for exercise and supporting the motivation to use these opportunities should be addressed for further enhancement.