To analyze baseline erythrocyte sedimentation rates (ESR) in cohorts of patients with rheumatoid arthritis (RA), which had been included in a review concerning longterm mortality, in reports published between 1973 and 2008, with baseline observations between 1954 and 2000.
A computer search and complementary review of the literature had identified 84 unique cohorts with RA for which mortality over 5-40 years was reported. Baseline ESR data were available for 23 of the 84 cohorts. Mean and median ESR, age, disease duration, and rheumatoid factor (RF) status were compiled and analyzed in tertiles according to first year of patient recruitment.
Among 7 cohorts recruited initially between 1954 and 1980, median ESR at baseline was 47 mm/h (mean 50 mm/h, range 43-66), compared to median 38 mm/h (mean 41 mm/h, range 34-64) among 8 cohorts recruited between 1981 and 1984, and median 36 mm/h (mean 35 mm/h, range 28-42) among 8 cohorts recruited between 1985 and 1996. The lowest mean ESR among 7 cohorts with baseline in 1980 or earlier was 43 mm/h, and the highest reported mean ESR among 8 cohorts recruited after 1985 was 42 mm/h. In 3 cohorts recruited after 1985 from Sweden, Finland, and Spain, mean baseline ESR was < 30 mm/h.
Mean ESR fell by 30% in cohorts of patients with RA recruited before 1981 compared to cohorts recruited after 1984. This decline may reflect changes in both the natural history and approaches to therapy of RA.