Table 5.

Results of a regression analysis with Rx-Misuse as the dependent variable

	Beta	P	Tolerance	F(df)	P	Adjusted R2	F(df) Change	P of F Change
Model 1				F(4,645) = 6.01	<0.001	0.03	F(4,645) = 6.01	<0.001
Sex	0.18	<0.001	0.99
Age	–0.01	0.78	0.98
Ethnicity	–0.03	0.49	0.86
Race	–0.06	0.19	0.85
Model 2				F(5,644) = 7.93	<0.001	0.05	F(1,644) = 15.07	<0.001
Sex	0.18	<0.001	0.99
Age	0.00	0.86	0.98
Ethnicity	–0.03	0.42	0.86
Race	–0.03	0.42	0.84
Pain Intensity Composite	0.15	<0.001	0.98
Model 3				F(6,643) = 25.49	<0.001	0.19	F(1,643) = 106.79	<0.001
Sex	0.18	<0.001	0.99
Age	0.04	0.27	0.97
Ethnicity	–0.03	0.47	0.86
Race	–0.03	0.42	0.84
Pain Intensity Composite	0.06	0.08	0.93
Negative Affect Composite	0.38	<0.001	0.93
Final Model				F(17,632) = 9.59	<0.001	0.18	F(`11, 632) = 0.936	0.51
Sex	0.18	<0.001	0.95
Age	0.05	0.17	0.88
Ethnicity	–0.03	0.41	0.85
Race	–0.04	0.30	0.80
Pain Intensity Composite	0.06	0.18	0.63
Negative Affect Composite	0.36	<0.001	0.28
Global Health Mental Score	–0.01	0.91	0.30
Social Isolation	0.02	0.66	0.41
Pain Behavior	0.04	0.44	0.46
Satisfaction with Social Roles	–0.07	0.18	0.46
Pain Interference	0.05	0.43	0.38
Sleep Impairment	–0.07	0.25	0.35
Fatigue	0.03	0.55	0.40
Sleep Disturbance	0.06	0.22	0.50
Global Health Physical Score	0.09	0.18	0.29
Emotional Support	0.04	0.36	0.70
Physical Function	0.05	0.29	0.48

The first step included all demographic measures as independent variables. The second and third steps included Pain Intensity and negative affect composite measures as independent variables, respectively. All other PROMIS measures were subsequently added, but none of them resulted in a significant contribution. The analysis thus indicated that composite negative affect was the most important predictor, above and beyond both demographic and Pain Intensity measures.

PROMIS = Patient-Reported Outcomes Measurement Information System.