TABLE 4.

Multiple linear regression models aiming to establish the adjusted predictive value (R²) for baseline parameters predicting analgesic response to duloxetine treatment. Model 1 contains all baseline parameters, whereas Model 2 was constructed using backwards selection and aimed to identify independent predictors (bold numbers in Model 2 are significant independent predictors)

Model 1	Standardized β‐values
	BPI worst pain	BPI average pain	WOMAC pain	WOMAC total
Adjusted R2	61.8%	70.3%	21.3%	25.3%
cPDT (ipsi)	0.021	−0.168	−0.084	−0.274
cPDT (contra)	−0.103	−0.404	−0.529	−0.701
cPTT (ipsi)	−0.013	0.411	0.114	0.718
cPTT (contra)	−0.192	−0.223	−0.043	−0.303
TSP	−0.215	−0.033	−0.102	−0.069
CPM	0.080	−0.026	0.153	−0.039
BPI Worst pain	0.996	0.158	0.134	−0.001
BPI Average pain	−0.047	0.665	−0.030	0.080
WOMAC pain	0.091	0.301	0.879	0.250
WOMAC total	−0.315	−0.286	−0.235	0.644
HADS	−0.610	−0.441	−0.530	−0.675
PCS	−0.038	0.006	0.072	0.045

Model 2	Standardized β‐values
	Worst pain	Average pain	WOMAC pain	WOMAC total
Adjusted R2	75.6%	75.3%	48.6%	45.7%
cPDT (ipsi)
cPDT (contra)		−0.342	−0.491	−0.538
cPTT (ipsi)
cPTT (contra)	−0.237
TSP	−0.240*
CPM
BPI Worst pain	0.999
BPI Average pain		0.743
WOMAC pain			0.787
WOMAC total	−0.255			0.781
HADS	−0.611	−0.441	−0.515	−0.650
PCS

Abbreviations: BPI, Brief Pain Inventory; contra, contralateral side to the most osteoarthritic affected knee; cPDT, cuff pain detection threshold; CPM, conditioned pain modulation; cPTT, cuff pressure pain tolerance threshold; HADS, Hospital Anxiety and Depression Score; ipsi, ipsilateral side to the most osteoarthritic affected knee; PCS, Pain Catastrophizing Scale; TSP, temporal summation of pain; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.