Concurrent hypertension and obesity and the risk of incident heart failure: insights from two prospective cohort studies
D Du, Y Chen, W Li, Z Li, W Chen, R HuangAbstract
Background
Hypertension and obesity commonly coexist and are major contributors to incident heart failure (HF). However, whether their combined effect exceeds the sum of their individual risks and whether early subclinical states—such as elevated blood pressure and preclinical obesity—already confer excess HF risk remain unclear. In addition, the consistency of HF risk prediction across different obesity definitions, including the recently proposed clinical/preclinical obesity framework, has not been systematically evaluated.
Purpose
To quantify the joint and additive effects of hypertension and obesity on incident HF, assess HF risk in elevated blood pressure and preclinical obesity, and compare HF risk prediction across traditional and multidimensional obesity definitions.
Methods
Data from the UK Biobank (n=444,754) and the Tongzhou cohort (n=10,459) were analyzed. Participants were categorized into four groups: neither condition, obesity alone, hypertension alone, and both. Obesity was defined using BMI, central obesity, combined “BMI + central” metrics, and the clinical obesity construct. Kaplan–Meier curves and multivariable Cox models were used to estimate HF risk. Joint effects of elevated blood pressure and pre-obesity were additionally examined. To determine whether the combined effect of hypertension and obesity exceeded the sum of their individual effects on HF risk, additive interaction was quantified using the relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (SI).
Results
The prevalence of concurrent hypertension and obesity ranged from 18.0–25.9% in the UK Biobank and 23.1–37.3% in Tongzhou. Across all definitions and cohorts, coexistence of the two conditions conferred the highest HF risk. In the UK Biobank, compared with participants without either condition, obesity alone (HR 1.79 [1.66–1.94]) and hypertension alone (HR 1.69 [1.61–1.77]) were associated with increased HF risk, while coexistence of both conferred the greatest risk (adjusted HR 3.14 [3.00–3.30]). Significant positive additive interaction was observed across multiple adiposity definitions; for example, central obesity showed a RERI of 0.67 (95% CI 0.55–0.79), AP of 0.23 (95% CI 0.19–0.27), and SI of 1.54 (95% CI 1.39–1.70), indicating excess risk beyond the sum of individual effects. Findings were directionally consistent in Tongzhou, although additive interaction did not reach statistical significance, likely due to limited power. Notably, individuals with both elevated blood pressure and pre-obesity already showed elevated HF risk (HR 1.20–1.29).
Conclusion
Hypertension and obesity synergistically increase HF risk beyond their individual effects, and excess risk is evident even at preclinical stages.Figure1Figure 2