Abstract Body (Do not enter title and authors here): Background: Obesity is a major risk factor for the onset and progression of cardiovascular-kidney-metabolic (CKM) conditions. However, there is substantial epidemiological and phenotypic heterogeneity across the spectrum of body mass index (BMI), and whether the contemporary prevalence of CKM conditions varies according to BMI in the US population has not been rigorously evaluated.

Methods
In this serial cross-sectional analysis of nonpregnant US adults aged ≥20 years participating in the nationally representative pre-pandemic National Health and Nutrition Examination Survey (2017-March 2020), we evaluated the prevalence of CKM conditions (cardiovascular disease [atherosclerotic cardiovascular disease (ASCVD) or heart failure (HF)], at least moderate-risk chronic kidney disease [CKD], and metabolic disease [type 2 diabetes (T2D) or metabolic dysfunction-associated steatotic liver disease (MASLD)] by BMI category (18.5-<25, 25-<30, 30-<35, 35-<40, and ≥40 kg/m²). Associations between each BMI category with prevalent CKM conditions were expressed as prevalence ratios (PR) with 95% CI, estimated using Poisson regression.

Results
Among 6,337 US adults (mean age, 48 years; 51% women), 26% had BMI 18.5-<25, 32% had BMI 25-<30, and 42% had BMI ≥30 kg/m². Nearly half (48%) of US adults with BMI ≥40 kg/m² were aged <45 years. CKM multimorbidity (≥2 CKM conditions) generally increased with increasing BMI category; 4.2% among those with BMI 18.5-<25 vs. 21.3% among those with BMI ≥30 kg/m² (Figure, A). Overall, increasing BMI was associated with a higher prevalence of all CKM conditions (P≤0.001 for all), with strongest associations observed for MASLD (BMI ≥40 vs. 18.5-<25 kg/m²; PR, 20.8, 95% CI 12.8-33.8; P<0.001), T2D (BMI ≥40 vs. 18.5-<25 kg/m²; PR, 5.8, 95% CI 4.3-7.8; P<0.001), and HF (BMI ≥40 vs. 18.5-<25 kg/m²; PR, 5.2, 95% CI 2.7-10.1; P<0.001) (Figure, B).

Conclusions
This analysis highlights the robust association between higher BMI and the prevalence of CKM conditions among US adults, supporting weight management as a core component of comprehensive CKM-oriented care strategies. These findings also support efforts to enhance screening and management for the full spectrum of CKM conditions in overweight/obesity.