Table 5a: Reduced Logistic Regression Model of HAQ-DI, Disease Type, and Disease Duration on WD. Variables: Sex, Age, and ‘Less than High School Education’ were Removed from the Model

Explanatory Variable (X) βXEstimate Standard Error Odds Ratio Wald Test p-Value
 N 164 - - -
 HAQ-DI score  1.775 0.323 5.902 <0.001
 Disease type 0.032
 Indicator lcSSc 0.743 0.473 2.102 0.116
 Indicator dcSSc 1.316 0.541 3.728 0.015
 Self-reported disease duration 0.043 0.021 1.044 0.042
 Constant -2.93 0.492 0.053 <0.001

No statistically important collinearity between the HAQ-DI and any of the independent factors was observed.