Table 1

 Demographic and treatment characteristics

1970s (n = 98)1980s (n = 222)1990s (n = 98)p Value*
DMARD, disease-modifying antirheumatic drug.
Continuous variables are in medians (Med) and interquartile ranges (IQRs) of variables are reported.
*One-way analysis of variance of means of normally distributed continuous variables; Kruskal–Wallis test for non-normally distributed variables; χ2 test for dichotomous variables. Comorbidity scale, number of comorbid conditions (0–11); DMARD, % of person-time, proportion of follow-up time on various DMARD regimens; Combination therapy, any combination of two or more DMARDs; Glucocorticoids, low-dose glucocorticoids.
Female (%)7174760.79
Ethnic origin
    Caucasian (%)949289
    Hispanic (%)124
    African-American (%)551
    Other (%)0130.20
Comorbidity score 0–11, Med (IQR)1 (1)0 (1)1 (1)0.48
DMARD, % of person-time in follow-up<0.01
    None634514
    Penicillamine1030
    Hydroxychloroquine71523
    Gold13135
    Sulfasalzine012
    Methotrexate62245
    Combination therapy1111
Glucocorticoids, % of person-time131329<0.01
Length of follow-up in years, Med (IQR)7.2 (3.2)6.6 (4.0)4.6 (3.8)<0.01