Predictive Value of Pain Sensitization Associated with Response to Exercise Therapy in Patients with Knee Osteoarthritis: A Prospective Cohort Study

Figures & data

Table 1 Demographic Data in Responder and Non-Responder Groups

Variables	Responder Group	Non-Responder Group	P
No. patients, n (%)	65 (71.4)	26 (28.6)
Age, mean ± SD	67.6±9.2	69.7±10.3	0.310
Sex (percentage female)	75.3	84.6	0.411
BMI, mean ± SD (kg/m²)	24.3±3.9	25.1±3.3	0.160
Pain duration, mean ± SD (months)	39.4±41.6	69.3±56.3	<0.01
Baseline NRS	5.0±1.7	6.1±1.9	<0.01
KL grade
1	26 (40.0)	9 (34.6)	0.401
2	22 (33.9)	6 (23.1)
3	14 (21.5)	10 (38.4)
4	3 (4.6)	1 (3.9)

Abbreviations: SD, standard deviation; BMI, body mass index; NRS, numerical rating scale; KL, Kellgren–Lawrence.

Figure 1 PPT and TSP at the knee, tibia, and forearm in the responder (white) and non-responder groups (gray).

Notes: Significant differences between the groups were found for PPT at all measurement sites and TSP at the knee and tibialis anterior. No significant difference is observed in TSP at the extensor carpi radialis longus. *P<0.05; ***P<0.001.

Abbreviations: PPT, pressure pain threshold; TSP, temporal summation of pain; VAS, visual analog scale.

Table 2 AUC, Sensitivity, and Specificity for Recommended Cutoff Points

Variables	AUC	95% CI	Cutoff Point (Sensitivity, Specificity)
Pain duration (months)	0.674	0.550–0.798	42.0 (65.4%, 66.2%)
Baseline NRS	0.673	0.553–0.793	4.5 (80.8%, 47.7%)
Knee PPT (kPa)	0.868	0.790–0.947	241.5 (81.5%, 84.6%)
Tibia PPT (kPa)	0.849	0.768–0.930	307.5 (83.1%, 73.1%)
Forearm PPT (kPa)	0.754	0.650–0.859	318.5 (64.6%, 76.9%)
Knee TSP (mm)	0.771	0.653–0.889	15.5 (69.2%, 83.0%)
Tibia TSP (mm)	0.662	0.522–0.802	14.0 (53.8%, 89.2%)
Forearm TSP (mm)	0.613	0.472–0.753	16.5 (34.6%, 93.8%)

Abbreviations: AUC, area under the curve; CI, confidence interval; NRS, numerical rating scale; PPT, pressure pain threshold; TSP, temporal summation of pain.