Over the last 20 years, obesity in childhood and adolescence has become a major public health concern due to dramatically increasing prevalence rates. We evaluated the outcome of 294 children (135 girls, 159 boys) aged 6-16 years (median 10.9 years) enrolled in a single centre outpatient obesity intervention programme consisting of periodical visits to the outpatient unit with regular medical and dietetic counselling aiming at a modification of dietary and activity patterns of patients and parents. The average number of visits to the outpatient unit was 3.6 (SD 2.7) with a mean visit interval of 62.1 days. A mean drop-out rate of 27.5% between each scheduled appointment occurred. In a stepwise regression model, neither reduction of the standard deviation score of patients' body mass index (BMI-SDS) nor dietary counselling contributed to the total number of visits. The only significant contributor was the patients' initial BMI-SDS explaining 4.6% of the variance of attended visits adjusted for age and sex. Segregation of the patients into an "obesity" (initial BMI-SDS >/=90th percentile, at least three visits attended, n=59) and an "excessive obesity" (initial BMI-SDS >/=99th percentile, at least four visits attended, n=75) subgroup showed a mean reduction of BMI-SDS in the "obesity" group at visit three of 0.14 (SD 0.21, P<0.0001), and in the "excessive obese" group at visit four of 0.17 (SD 0.22, P<0.001). In a stepwise regression model, the mean interval between visits and regular dietary counselling explained 11.7% of the variance of BMI-SDS reduction at visit three in both subgroups.
Conclusion: there is an urgent need for efficient strategies to improve adherence of outpatients to obesity treatment since, in terms of reduction in body mass index standard deviation score, a beneficial outcome can be achieved for compliant obese children and adolescents.