Abstract 11553: Does the Metabolic Syndrome Cluster Provide Incremental Prognostic Information Over the Individual Components? Post Hoc Analysis of the AIM-HIGH Trial
Background: Controversy persists as to whether the cluster of risk factors comprising metabolic syndrome (3 or more of the 5 ATP-III/ADA components) confers independent prognostic value over and above the individual constituent risk factors.
Methods: We performed a post hoc analysis of AIM-HIGH Trial patients (n=3,414) of whom 2,846 (83%) had metabolic syndrome (MS) at baseline. Patients (pts) with MS were subdivided further according to the number of MS components (3: n=1,660; 4: n=1,060; 5: n=126). Baseline characteristics, comorbidities, and lipids/lipoproteins were compared among MS subgroups vs. pts without MS. Pts were also divided into 4 subgroups by diabetes mellitus (DM) and MS status: DM(-), MS(-); DM(-), MS(+); DM(+), MS(-); DM(+), MS(+). Cox regression models were used to adjust for relevant covariates and the number of MS criteria during a mean 3-year follow-up.
Results: Compared to pts without MS (n=568), there were no baseline differences in comorbidities or medical history but, as expected, pts with MS had significantly higher mean BP (129/75 mmHg vs. 124/71 mmHg); BMI (32 Kg/M2 vs. 26 Kg/M2; waist circumference (43.4 in vs. 36.7 in); TG 185 mg/dL vs. 170 mg/dL); insulin (21.5 vs. 13.2) and HOMA1-IR (6.1 vs. 3.5), and FBS (112 mg/dL vs. 104 mg/dL), with similar HDL-C (34.5 mg/dL vs. 35.6 mg/dL); each comparison, P< 0.001. Among pts with 5 vs. 3 MS criteria, BP, BMI, waist circumference, insulin, and HOMA1-IR were higher, but FBS was lower. The 5-component primary composite endpoint occurred in 16.4% of pts with vs.15.1% without MS (HR 1.10, 95%CI 0.88-1.37; P=0.41). Compared to pts without MS, there were no significant differences in the primary or any secondary endpoint among MS pts with 3, 4, or 5 criteria. Lastly, 3-year outcomes among DM/MS subgroups were: DM(-), MS(-): 14%; DM(-), MS(+): 15%; DM(+), MS(-): 25%; DM(+), MS(+): 19%; P=0.001.
Conclusion: Despite a higher prevalence of abnormal clinical risk factors (BP, BMI, waist circumference, lipids) and increased insulin/HOMA1-IR levels in MS pts, there were no differences in any trial-related clinical outcomes at 3 years compared to pts without MS. Thus, the MS cluster does not appear to provide independent, incremental value over the individual component risk factors in this high-risk population.
- © 2013 by American Heart Association, Inc.