Table 3. Multivariate model predicting pain interference over time*.
| Predictor of pain interference with movement | Coefficient (95% CI)† | P value |
|---|---|---|
| Educational status | ||
| Illiterate | 0.478 (0.004,0.952) | 0.048 |
| Marital status | ||
| Single | -0.670 (-1.316,-0.023) | 0.042 |
| Widowed/divorced | -0.338 (-1.020,0.343) | 0.330 |
| Physical Status | ||
| ASA PS 2 | 0.922 (0.231,1.613) | 0.009 |
| Type of anesthesia | ||
| Spinal anesthesia | 0.706 (0.246,1.166) | 0.003 |
| Duration of surgery | 0.179 (-0.155,0.512) | 0.295 |
| Chronic pain severity | 0.161 (0.057,0.265) | 0.002 |
| Pain intensity | ||
| Worst pain | 0.366 (0.225,0.507) | <0.01 |
| Current pain | 0.390 (0.230,0.551) | <0.01 |
| Time in pain | 0.008 (-0.001,0.018) | 0.093 |
| Perceived care | ||
| Relief received | -0.027 (-0.041,-0.013) | <0.01 |
| Predictors of pain interference with activities in bed | ||
| Time since surgery, h | -0.021 (-0.027, -0.015) | <0.01 |
| Worst pain | 0.319 (0.225, 0.413) | <0.01 |
| Current pain | 0.282 (0.174, 0.390) | <0.01 |
| Time in severe pain | 0.021 (0.015, 0.027) | <0.01 |
| Predictors of pain interference with sleep | ||
| Worst pain | 0.352 (0.230, 0.475) | 0.001 |
| Current pain | 0.302 (0.163, 0.440) | 0.001 |
| Time in severe pain | 0.021 (0.007, 0.034) | 0.003 |
| Perceived relief | -0.022 (-0.044, -0.001) | 0.044 |
| Predictors of pain interference with breathing and coughing | ||
| Physical status | ||
| ASA PS 2 | 0.671 (0.022, 1.321) | 0.043 |
| Type of anesthesia | ||
| Spinal anesthesia | -1.222 (-1.879, -0.565) | <0.01 |
| Ketamine anesthesia | -0.194 (-1.292, 0.904) | 0.729 |
| Chronic pain severity | 0.253 (0.100, 0.407) | 0.001 |
| Type of surgery | ||
| Gynecologic surgery | 0.099 (-0.476, 0.674) | 0.736 |
| Orthopedic surgery | -1.235 (-2.135, -0.335) | 0.007 |
| Time since surgery | -0.015 (-0.026, -0.004) | 0.006 |
| Pain intensity | ||
| Worst pain | 0.199 (0.051, 0.347) | 0.008 |
| Current pain | 0.268 (0.145, 0.391) | <0.01 |
| Perception of care | ||
| Relief received | -0.020 (-0.037, -0.004) | 0.016 |
| Predictors of pain causing the feeling of anxiousness | ||
| Marital status | ||
| Single | -0.957 (-1.649,-0.265) | 0.007 |
| Widowed/divorced | 0.549 (-1.183,2.280) | 0.535 |
| Type of anesthesia | ||
| Spinal anesthesia | 0.087 (-0.658,0.831) | 0.820 |
| Ketamine anesthesia | -1.178 (-1.981,-0.376) | 0.004 |
| Duration of surgery | -0.117 (-0.609,0.375) | 0.641 |
| Chronic pain severity | 0.179 (0.005,0.352) | 0.044 |
| Type of surgery | ||
| Gynecologic surgery | -1.002 (-1.685,-0.319) | 0.004 |
| Orthopedic surgery | 0.161 (-0.835,1.157) | 0.752 |
| Time since surgery | -0.004 (-0.014,0.005) | 0.379 |
| Pain intensity | ||
| Worst pain | 0.308 (0.179,0.437) | <0.01 |
| Current pain | 0.253 (0.131,0.375) | <0.01 |
| Predictors of pain causing the feeling of helplessness | ||
| Marital status | ||
| Single | 0.727 (-1.408, -0.046) | 0.036 |
| Widowed/divorced | 0.799 (-1.044, 2.643) | 0.395 |
| Religion | ||
| Muslim | 0.418 (0.003, 0.833) | 0.049 |
| Protestant | -0.273 (-0.817, 0.272) | 0.326 |
| Type of anesthesia | ||
| Spinal anesthesia | 0.280 (-0.440, 0.999) | 0.446 |
| Ketamine anesthesia | -1.494 (-2.305, -0.684) | <0.01 |
| Chronic pain severity | 0.188 (0.032, 0.343) | 0.018 |
| Type of surgery | ||
| Gynecologic surgery | -0.823 (-1.441, -0.206) | 0.090 |
| Orthopedic surgery | 0.600 (-0.554, 1.754) | 0.308 |
| Pain intensity | ||
| Worst pain | 0.240 (0.117, 0.363) | <0.01 |
| Current pain | 0.205 (0.112, 0.298) | <0.01 |
Abbreviations: CI, confidence interval; ASA PS-I, American society of Anesthesiologists physical status classification I.
*Variables tested that did not predict interference with movement included age, ethnic group, type of surgery and time spent in severe pain. Variables that did not predicted activities in bed and sleep included age, gender, educational status, marital status, physical status, ethnic group, religion, type of surgery and anesthesia, chronic pain severity and time spent in severe pain. Variables tested but not predicted interference with breathing and coughing included sex, religion, marital status, and ethnic background. Variables tested that did not predicted anxiousness and helplessness are age, gender, educational status, and least pain intensity.
†For risk factors with only main effects, the coefficient indicates mean difference from the reference group (e.g., the reference group for marital status is married, for educational status is literate, for type of anesthesia is general anesthesia, for type of surgery is general surgery, for physical status is ASA PS I, for religion is orthodox, for ethnicity is Amhara). Time is treated as continuous variable because of linearity of outcome variable over time.