Cardiovascular-Kidney-Metabolic Health in US Adults Under the 2026 Multisociety Guideline: Stage Redistribution From 1999 to 2023 and Population Burden Through 2050

Background The 2026 multisociety guideline frames cardiovascular, kidney, and metabolic health as a staged pathway. National surveillance should distinguish early-risk expansion from advanced-disease accumulation because they require different responses. Methods We analysed 66,553 adults aged 20 years or older across 11 non-overlapping National Health and Nutrition Examination Survey periods from 1999-2000 to August 2021-August 2023. Staging incorporated adiposity, glycaemia, metabolic risk, KDIGO kidney risk, PREVENT 10-year cardiovascular disease risk, and clinical cardiovascular disease. We estimated age-standardised prevalence and secular trends and projected population burden through 2050. Robustness analyses included complete-case estimation, alternative staging thresholds, exclusion of the latest survey period, and rolling temporal validation. Findings In 2021-2023, 88.5% (95% CI 87.2-89.9) of US adults were in stage 1 or higher, and 62.1% (59.9-64.4) were in stages 2-4. From 1999-2000 to 2021-2023, stage 0 decreased by 4.3 percentage points and stage 1 increased by 7.9 points, whereas stages 3-4 remained stable. Adiposity and diabetes increased, while hypertension and hypertriglyceridaemia declined. The prevalence of stages 2-4 ranged from 54.4% among college graduates to 69.6% among adults with less than a high-school education. Under population ageing alone, 189.5 million adults were projected to be in stages 2-4 by 2050. Rolling temporal validation yielded a mean absolute error of 1.6 percentage points. Interpretation The distribution of CKM stages in the US population shifted towards earlier metabolic risk without a parallel increase in advanced-stage disease. Policy should combine upstream prevention, equitable access to detection and treatment, and preparation for a growing older population requiring integrated care.