Table 8

Multiple regression analysis showing how the three domains of the Revised Fibromyalgia Impact Questionnaire predict subscales of the 36-Item Short Form Health Survey

SF-36 subscales (dependent variable)

R and R2 predicted by combined FIQR domains

FIQR function

FIQR overall impact

FIQR symptoms


Physical functioning

R = 0.80a

β = -0.803a

β = -0.005

β = 0.015

R2 = 0.62

pr = -0.641a

pr = -0.004

pr = 0.014

Role limitation due to physical health

R = 0.55a

β = -0.270b

β = -0.261c

β = -0.058

R2 = 0.29

pr = -0.200b

pr = -0.167c

pr = -0.040

Role limitation due to emotional health

R = 0.45a

β = 0.170

β = -0.234c

β = -0.362d

R2 = 0.19

pr = 0.120

pr = -0.140c

pr = -0.237d

Energy/Fatigue

R = 0.55a

β = 0.029

β = -0.133

β = -0.465a

R2 = 0.30

pr = 0.022

pr = -0.080

pr = -0.312a

Emotional well-being

R = 0.58a

β = 0.308d

β = -0.210c

β = -0.593a

R2 = 0.32

pr = 0.231d

pr = -0.137c

pr = -0.392a

Social functioning

R = 0.57a

β = 0.066

β = -0.287b

β = -0.369d

R2 = 0.32

pr = 0.050

pr = -0.186b

pr = -0.256d

Pain

R = 0.70a

β = -0.175c

β = -0.219c

β = -0.362a

R2 = 0.48

pr = -0.0152c

pr = -0.163c

pr = -0.285a

General health

R = 0.57a

β = -0.185c

β = -0.085

β = -0.347d

R2 = 0.31

pr = -0.140c

pr = -0.056

pr = -0.241d


aP < 0.0001; bP < 0.01; cP < 0.05; dP < 0.001. First column: adjusted R-square (R2) × 100 indicates the total variance in 36-Item Short Form Health Survey (SF-36) subscale accounted for by the common

    and
unique variance in Revised Fibromyalgia Impact Questionnaire (FIQR) function, overall, and symptom domains taken together. Multiple regression (R) indicates the size of correlation between three FIQR domains as predictors taken together with the SF-36 subscale as criterion. Columns 2, 3, and 4 present the standardized regression (β) coefficients, which represent the unique contribution of the predictor variable, and the partial correlation (pr) coefficients, which represent the correlation for the one (FIQR) domain with the SF-36 subscale after controlling for the other two (FIQR) domains.

Bennett et al. Arthritis Research & Therapy 2009 11:R120   doi:10.1186/ar2783

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