Additive value of interleukin-6 and C-reactive protein in risk prediction for all-cause and cardiovascular mortality among a representative adult cohort in Taiwan.

Background/purpose: Interleukin-6 (IL-6) and C-reactive protein (CRP) are inflammatory makers of potential interest in all-cause and cardiovascular death risk prediction, but their additive explanatory value to established risk factors is not well documented among nonwestern populations.

Methods: We investigated the additive value of IL-6 and CRP to the Framingham risk score and lifestyle factors in predicting all-cause and cardiovascular mortality among a population-representative sample of 1023 adults aged 54 years and above in Taiwan.

Results: A total of 351 deaths and 82 cardiovascular deaths were identified (median follow-up = 11.2 years). After adjustment for established risk factors, elevated IL-6 and CRP levels were associated with a higher risk of all-cause death: the hazard ratios for the highest risk quartile compared with the lowest quartile were 3.64 (95% confidence interval, 2.44-5.44) for IL-6 and 2.31 (95% confidence interval, 1.62-3.29) for CRP. IL-6 was also significantly associated with cardiovascular mortality. For both all-cause and cardiovascular mortality, IL-6 yielded a substantial and significant increase in the area under the receiver operator characteristic curve (change in the area under the receiver operator characteristic curve = 0.036 and 0.024, respectively), but CRP did not (change in the area under the receiver operator characteristic curve = 0.004 and 0.009, respectively).

Conclusion: Although both IL-6 and CRP were significantly associated with all-cause mortality, only IL-6 provided a substantial improvement in discrimination. Similarly, IL-6 demonstrated a notable prognostic value for predicting cardiovascular mortality, but not CRP. These findings provide further support for the role of inflammation in the deterioration of health at older ages among a nonwestern population.