Impact of High-Sensitivity C-Reactive Protein Cutoff Selection on Cardiovascular Risk Classification Beyond Lipid Measurements in Korean Adults: A KNHANES 2024 Study

Figures

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  Figure 1. Flow diagram of the study population. After excluding participants aged < 20 years, pregnant women, and those with missing hsCRP measurements, 5769 adults with available hsCRP measurements and results for all four lipid tests were included in the primary analysis. Participants with hsCRP concentrations ≥ 10 mg/L were retained in the primary analysis. Subgroup analysis 1 included 3861 participants with normal results for all four lipid tests, whereas subgroup analysis 2 included 5508 participants with complete covariate data for multivariable logistic regression. For the sensitivity analysis, 89 participants with hsCRP concentrations ≥ 10 mg/L were excluded, leaving 5680 participants.

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  Figure 2. Distribution of high-sensitivity C-reactive protein (hsCRP) concentrations in Korean adults. The histogram and density curve show the survey-weighted distribution of hsCRP concentrations among non-pregnant Korean adults aged ≥ 20 years in the 2024 Korea National Health and Nutrition Examination Survey. Vertical dashed lines indicate hsCRP cutoffs of 1, 2, 3, and 10 mg/L.

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  Figure 3. Subgroup-specific prevalence of elevated hsCRP according to demographic and lipid categories. Survey-weighted prevalence of elevated hsCRP was estimated across age, sex, and lipid subgroups. Elevated hsCRP was evaluated using clinically relevant cutoffs, including hsCRP ≥ 1 mg/L, hsCRP ≥ 2 mg/L, and hsCRP > 3 mg/L. Color intensity represents the survey-weighted percentage within each subgroup.

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  Figure 4. Additional detection of elevated hsCRP at different cutoffs among 3861 lipid-normal Korean adults. Additional detection rates were estimated among participants without conventional lipid abnormalities. Lipid normality was defined as the absence of total cholesterol ≥ 240 mg/dL, directly measured LDL-C ≥ 160 mg/dL, triglycerides ≥ 200 mg/dL, and low HDL-C, defined as HDL-C < 40 mg/dL in men and <50 mg/dL in women. Bars show survey-weighted percentages of lipid-normal participants with hsCRP ≥ 1 mg/L, hsCRP ≥ 2 mg/L, or hsCRP > 3 mg/L. Error bars indicate 95% confidence intervals. Percentages above the bars indicate weighted estimates, while numbers inside the bars indicate the corresponding unweighted numerators. Results are shown for the overall population and according to sex and age group.

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  Figure 5. Factors associated with elevated hsCRP levels at different cutoffs: survey-weighted multivariable logistic regression analyses. Survey-weighted adjusted ORs and 95% CIs were estimated using multivariable logistic regression models for hsCRP ≥ 1 mg/L, hsCRP ≥ 2 mg/L, and hsCRP > 3 mg/L. The reference categories were age 20–29 years, men, never-smokers, non-obesity, normal glucose status, no physical activity limitation, no alcohol use, no hypertension, no physician-diagnosed dyslipidemia, no history of cardiovascular disease, no kidney disease, total cholesterol < 240 mg/dL, LDL-C < 160 mg/dL, triglycerides < 200 mg/dL, and HDL-C ≥ 40 mg/dL in men or ≥50 mg/dL in women. Points indicate adjusted odds ratios, and horizontal lines indicate 95% confidence intervals. Abbreviations: BMI, body mass index; CI, confidence interval; eGFR, estimated glomerular filtration rate; HDL-C, high-density lipoprotein cholesterol; hsCRP, high-sensitivity C-reactive protein; LDL-C, low-density lipoprotein cholesterol.