BACKGROUND: Higher rates of weight-related comorbidities are associated with body mass index (BMI) in individuals who have overweight/obesity. The relationships between BMI, health outcomes and health-related costs differ across populations and geographic regions.
AIM: To assess the relationship between BMI, health state and economic costs among adults, including those with selected cardiometabolic comorbidities (type 2 diabetes [T2D], pre-diabetes; hypertension) in Brazilian adults.
METHOD: Data from three waves (2011, 2012, and 2015) of the Brazil National Health and Wellness Survey (NHWS) were used for this study (N=36,000). The NHWS is an Internet-based survey administered to a demographically representative sample of Brazilian adults (≥18 years). BMI category was calculated based on self-reported height and weight. Cardiometabolic comorbidities were self-reported. Health outcomes included: health status (SF-12/36v2); estimated annual indirect costs based on lost work productivity and wage information; and estimated annual direct costs based on self-reported resource use and published costs (physician costs: private = CBHPM, public = SIGTAP; hospitalisation costs: private = Unidas, public = AIH). Differences among BMI categories were compared in generalised linear models controlling for demographics and health history covariates.
RESULTS: The BMI distribution was as follows: normal weight (BMI ≥18.5 to <25 kg/m2) = 46.4%, overweight (BMI ≥25 to <30 kg/m2) = 34.9%, obesity class I (BMI ≥30 to <35 kg/m2) = 12.9%, obesity class II (BMI ≥35 to <40 kg/m2) = 3.7%, and obesity class III (BMI ≥40 kg/m2) = 2.1%. BMI category had a significant association with physical health status for all groups. Among all adults, indirect costs (R$884 [normal weight] to R$1,657 [obesity III]), physician visit costs (R$230–321), and hospitalisation costs (R$1,350–3,142) increased along with each BMI category (all p<0.05 relative to normal weight). Similar patterns were observed for patients with T2D (indirect: R$2,779–3,505; physician: R$256–431; hospitalisation: R$1,860–2,849 [obesity II]), pre-diabetes (indirect costs: R$2,057–3,570; physician costs: R$282–304; hospitalisation: R$917–2,987), and hypertension (indirect costs: R$2,965–3,269; physician costs: R$290–367; hospitalisation: R$1,838–2,553). 
DISCUSSION: Increasing BMI is associated with progressively worse health-related quality of life and economic costs; particularly for patients with T2D, pre-diabetes, and hypertension. Improved management of obesity could have substantial societal benefits.

Association between body mass index and health outcomes among Brazilians with and without cardiometabolic comorbidities