Multistate markov model analysis of metabolic syndrome progression in a community-based longitudinal cohort study

Background: Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that are strongly associated with cardiovascular disease and diabetes. However, there is limited evidence on how MetS develops from individual metabolic abnormalities. This study investigated which initial metabolic components accelerate the progression of MetS and analyzed how sex, age, and residential location affect these developmental trajectories. Methods: This study analyzed screening data from Changhua County (2005–2021) to conduct a retrospective generational study of 41,109 adults aged ≥ 30 years and 63,114 records. Metabolic abnormalities were categorized into four states (state 0–3), and transition rates were estimated using continuous-time multistate Markov models and analyzed based on initial abnormality type, sex, and age. Progression was defined as a continuous transition across the metabolic states from State 0 to 1, 1 to 2, and ultimately to State 3, reflecting the accumulation of metabolic abnormalities over time. Results: Triglyceride (TG) and waist circumference abnormalities exhibited the most rapid progression intensities (0.344 and 0.326/year, respectively). Crucially, the mean sojourn time—the expected duration individuals remained in each state before transitioning—was estimated at 3.07 years for State 1 with one abnormality and 2.79 years for State 2 with two abnormalities. The analysis revealed that women accumulated metabolic risk at a faster rate than men after midlife, while rural residents exhibited accelerated deterioration, specifically driven by their higher TG and WC levels compared to urban residents. Conclusion: MetS progression is rapid but reversible during the early stages. The short mean sojourn times warrant a recommendation for follow-up screening intervals of 2–3 years for individuals who present with one or more metabolic abnormalities, as this timeframe captures the window of opportunity for reversal. Public health interventions should prioritize lipid management and weight control, particularly targeting rural populations and postmenopausal women, who exhibit the steepest disease progression.