Table 1.
Potential predictors of the intercept, linear coefficient, and quadratic coefficient for pain at rest, pain with activity, and hours per day in pain
| Pain at rest (N = 188) | Pain with activity (N = 188) | Hours in pain (N = 185) | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Demographic characteristics | I | LC | QC | I | LC | QC | I | LC | QC |
| Age | x | x | x | x | |||||
| Sex | |||||||||
| Education level | |||||||||
| Cohabitation status | |||||||||
| Employment status | x | x | |||||||
| Preoperative clinical characteristics | |||||||||
| Body mass index | |||||||||
| Number of comorbidities | x | x | x | ||||||
| American Society of Anesthesiologists’ physical status classification | x | ||||||||
| Systolic blood pressure | |||||||||
| Diastolic blood pressure | |||||||||
| C-reactive protein | |||||||||
| Hemoglobin | |||||||||
| Pain characteristics | |||||||||
| Average pain prior to surgery | |||||||||
| Worst pain prior to surgery | x | x | |||||||
| Pain at rest, day of surgery | n/a | x | x | n/a | n/a | n/a | n/a | n/a | n/a |
| Pain with activity, day of surgery | n/a | n/a | n/a | n/a | x | x | n/a | n/a | n/a |
| Hours per day in pain, day of surgery | n/a | n/a | n/a | n/a | n/a | n/a | n/a | x | x |
| Pain interference with function | x | x | x | ||||||
| Perioperative characteristics: | |||||||||
| Side of knee surgery | x | x | |||||||
| Type of anesthesia | x | x | x | ||||||
| Length of surgery (minutes) | |||||||||
| Pain management characteristics | |||||||||
| Number of days with epidural analgesia | x | x | x | x | x | ||||
| Number of days with continuous femoral nerve block | x | x | x | x | x | ||||
| Number of days with ketamine | x | x | x | ||||||
| Average dose of opioids over 4 days | x | x | x | ||||||
| Symptoms | |||||||||
| Fatigue severity | x | x | x | ||||||
| Fatigue interference | x | ||||||||
| Depression | |||||||||
| Anxiety | x | x | x | ||||||
| Psychological characteristics from the BIPQ | |||||||||
| Consequences | x | x | |||||||
| Personal control | x | ||||||||
| Identity | x | x | x | ||||||
| Concern | x | ||||||||
| Emotional response | x | x | x | ||||||
I = intercept; LC = linear coefficient; QC = quadratic coefficient; BIPQ = Brief Illness Perception questionnaire; x = t values >2.0 in exploratory analyses.