The European Heart Journal has published data from a two year follow up of the Rimonabant In Obesity - Europe study. A summary of the article is available via the National Electronic Library for Medicine.
The original RIO-Europe study recruited 1,057 individuals with a body mass index (BMI) of 30kg/m2, or BMI 27kg/m2 and either hypertension or dyslipidaemia. Participants were randomised to placebo, rimonabant 5mg or rimonabant 20mg. At the end of follow up, originally one year, weight loss was 1.8kg, 3.4kg and 6.6kg respectively. The study also reported improvements in cardiovascular risk factors including waist circumference, lipids and blood glucose.
This article compares two year data with baseline levels. It should be noted that drop out was high in all groups with less than half the original participants continuing treatment for two years. Weight loss was 1.2kg, 2.9kg, and 5.5kg, again in the respective groups. These figures are calculated from last known values carried forward where participants have been lost to follow up. The authors of the study conclude that, "rimonabant 20 mg over 2 years promoted clinically relevant and durable weight loss".
It is apparent from the data that there was an average weight gain in the second year of follow up when compared to the end of year one weight loss averages. This is despite all patients being provided with a dietary regimen that equivalent to a 600kcal daily energy deficit.
Action: The results of the study highlight the challenges of continued and persistent weight loss, even when pharmacologically aided. It also serves to highlight that pharmacological treatment should be stopped immediately if continued weight loss is not observed.