C-reactive protein and all-cause mortality in a large hospital-based cohort

C-reactive protein (CRP), an acute-phase protein, is a sensitive systemic marker of inflammation and acute-phase reactions. Testing CRP concentrations at hospital admission may provide information about disease risk and overall survival.

All first-ever transmittals to the department of medical and chemical laboratory diagnostics for determination of low-sensitivity CRP (n = 274 515, 44.5% male, median age 51 years) between January 1991 and July 2003 were included [median follow-up time: 4.4 years (interquartile range, 2.3-7.4 years)]. The primary endpoint was all-cause mortality. Multivariate Cox regression adjusted for sex and age was applied for analysis.

Compared to individuals within the reference category (CRP <5 mg/L), hazard ratios (HR) for all-cause mortality increased from 1.4 (5-10 mg/L category) to 3.3 in the highest category (>80 mg/L, all P <0.001). CRP was associated with various causes of death. The relation of CRP to cancer death was stronger than to vascular death. Younger patients with increased CRP had relatively far worse outcome than older patients (maximal HR: < or =30 years: 6.7 vs >60 years: 1.7-3.7). Interestingly, both short- and long-term mortality were associated with increasing CRP concentrations (>80 mg/L: HR 22.8 vs 1.4).

Measurement of low-sensitivity CRP at hospital admission allowed for the identification of patients at increased risk of unfavorable outcome. Our findings indicate that close attention should be paid to hospitalized patients with high CRP not only because of very substantial short-term risk, but also long-term excess risk, the basis for which needs to be determined.