The aim of this study is to evaluate whether lipoprotein(a) (Lp(a)) acts as the acute phase reactant and whether changes of lipids are related to inflammation in rheumatoid arthritis (RA). Lp(a) and lipids were measured after an overnight fast, before and after 14 days use of antiinflammatory agents and correlated with laboratory findings in 21 untreated RA patients and 19 healthy controls. Nine (42.3%) of 21 RA patients and 6 (31.6%) of 19 controls had high Lp(a) levels (> 30 mg/dl) and the Lp(a) level was higher in RA patients compared with controls (27.1 +/- 5.3 vs 19.0 +/- 4.2 mg/dl) without significant difference (p > 0.05). There was no significant correlation between ESR and Lp(a) and lipids in RA patients except for HDL cholesterol (r = -0.563, p = 0.008). After antiinflammatory agent use for 14 days, change in ESR (ESRsample1-ESRsample2) was significantly and negatively correlated to changes in total and HDL cholesterols in RA patients. In conclusion, although Lp(a) tended to be higher in RA, we could not find a distinct acute phase pattern of Lp(a). But changes in total and HDL cholesterols were negatively correlated with inflammation in RA. Our data support the phenomenon that dyslipoproteinemia observed in RA is associated with inflammation.