The prognostic value of serum albumin in healthy older persons with low and high serum interleukin-6 (IL-6) levels

OBJECTIVE: We sought to determine the prognostic value of serum albumin for 4-year mortality among high-functioning persons who did or did not have ev idence of inflammation as indicated by high interleukin-6 (IL-6) levels. DESIGN: We used a case-cohort design of healthy, nondisabled older persons who had serum albumin and plasma IL-6 measured at baseline. Crude and multi ply adjusted (for sociodemographics and chronic diseases) proportional haza rds models were used to identify the effect of baseline levels of serum alb umin level on 4-year mortality among those with higher and lower levels of IL-6. RESULTS: Among subjects without evidence of IL-6-mediated inflammation (IL- 6 < 3.20 pg/mL), having a lower (<less than or equal to>4.4 g/dL) albumin l evel was associated with a multiply adjusted relative risk of 2.1 for 4-yea r mortality compared with those with higher albumin. In the presence of inf lammation (IL-6 greater than or equal to 3.20 pg/mL), higher and lower seru m albumin levels had similar risks (adjusted relative risks 4.0 and 3.8, re spectively) compared with the referent group (higher albumin and low IL-6). CONCLUSIONS: High serum albumin has a protective effect in healthy older pe rsons who do not have evidence of cytokine-mediated inflammation. This prot ective effect is not conferred in presence of inflammation. The mechanisms by which inflammation eliminates the protective effect of high albumin rema in to be determined.