OBJECTIVES

: Obesity is associated with elevated risks of developing major costly medical complications and impaired quality of life. The objective of this study was to create a core obesity model to compare weight management interventions, by assessing impacts on BMI and patho-physiological parameters to estimate long-term complications.

METHODS

: We developed a life-time Markov model with health states reflective of complications which: 1) are highly related to obesity according to the World Health Organization; 2) respond to weight loss, 3) have substantial consequences on costs, quality of life and/or life expectancy. Selected complications were: type 2 diabetes (T2D), obstructive sleep apnoea, cardiovascular disease (acute coronary syndrome [ACS], stroke), cancers (colorectal, endometrial and breast) and osteoarthritis resulting in knee replacement.

Actual short-term effects of specific interventions on BMI, blood pressure, lipids and HbA1c observed in clinical trials were translated into long-term risks of obesity complications, using published or newly developed risk-prediction equations.

RESULTS

: As an example, in a European cohort, mean age 45 years and BMI 37 kg/m, over a 10-year horizon the model predicted 5.0% mortality, 5.8% ACS and 2.1% stroke. Knee replacement occurred in 6.3% of the cohort and the proportion alive with T2D was 5.0%. Following a reduction of 3 BMI units, all other factors remaining unchanged, mortality dropped to 4.8%, with ACS and stroke incidences decreasing to 5.5% and 2.0%. The incidence of knee replacement was reduced to 4.4% and the proportion alive with T2D was 3.8%.

CONCLUSIONS

: The presented Core Obesity Model is novel in assessing the long-term effects of weight management interventions on such a comprehensive set of obesity medical complications. This model can therefore be used to inform cost-effectiveness analyses on the treatment of adult patients with obesity, with the usual limitations as no prospective long-term data exist on hard outcomes after intentional weight changes.