Table 2:
Characteristics of Extreme Pain Interference Phenotypes
| Low Interference Phenotype (N = 441) | High Interference Phenotype (N = 431) | p-value | |
|---|---|---|---|
| Sociodemographic and Participant Characteristics | |||
|
| |||
| Years Post-Injury, Median (IQR) | 5.4 (2.1, 14.5) | 5.4 (2.0, 14.6) | 0.9322 b |
|
| |||
| Age at Follow-Up, Mean (SD) | 46.1 (16.4) | 47.5 (13.9) | 0.1768 a |
|
| |||
| Sex, N Male (%) | 330 (74.8%) | 308 (71.5%) | 0.2617 c |
|
| |||
| Race† | |||
| White, N (%) | 355 (80.5%) | 293 (68.3.%) | < 0.0001 c |
| Black / African American, N (%) | 60 (13.6%) | 117 (27.2%) | < 0.0001 c |
| Asian, N (%) | 15 (3.4%) | 10 (2.3%) | 0.3448 c |
| American Indian / Alaskan Native, N (%) | 13 (2.9%) | 22 (5.1%) | 0.1018 c |
| Native Hawaiian / Pacific Islander, N (%) | 3 (0.7%) | 8 (1.9%) | 0.1180 c |
|
| |||
| Hispanic, Latino, or Spanish Ethnicity, N (%) | 40 (9.1%) | 54 (12.5%) | 0.0996 c |
|
| |||
| Marital Status at Follow-Up | 0.0009 c | ||
| Single/Other, N (%) | 150 (34.2%) | 155 (36.0%) | - |
| Married, N (%) | 191 (43.5%) | 140 (32.5%) | * |
| Separated/Divorced/Widowed, N (%) | 98 (22.3%) | 136 (31.6%) | * |
|
| |||
| Education Level at Follow-Up | < 0.0001 c | ||
| Less than High School, N (%) | 38 (8.7%) | 110 (25.5%) | * |
| High School, N (%) | 95 (21.7%) | 117 (27.1%) | - |
| Some College / Associate’s, N (%) | 169 (38.6%) | 142 (32.9%) | - |
| Bachelor’s or Higher, N (%) | 136 (31.1%) | 62 (14.4%) | * |
|
| |||
| Employment Status at Follow-Up | < 0.0001 c | ||
| Employed/Student, N (%) | 231 (52.6%) | 99 (23.1%) | * |
| Retired, N (%) | 139 (31.7%) | 235 (54.9%) | * |
| Unemployed, N (%) | 47 (10.7%) | 74 (17.3%) | * |
| Other, N (%) | 22 (5.0%) | 20 (4.7%) | - |
|
| |||
| Military History, N Yes (%) | 84 (19.0%) | 107 (24.8%) | 0.0391 c |
|
| |||
| Living Situation at Follow-Up | 0.0010 c | ||
| Alone, N (%) | 65 (14.8%) | 82 (19.0%) | - |
| Spouse / Significant Other, N (%) | 230 (52.5%) | 168 (39.0%) | * |
| Other Family, N (%) | 112 (25.6%) | 138 (32.0%) | - |
| Someone Else, N (%) | 31 (7.1%) | 43 (10.0%) | - |
|
| |||
| Illicit Drug Use at Follow-Up, N Yes (%) | 76 (17.4%) | 67 (15.6%) | 0.4822 c |
|
| |||
| Drinking Category at Follow-Up | < 0.0001 c | ||
| Abstaining, N (%) | 183 (42.0%) | 249 (58.6%) | * |
| Light, N (%) | 101 (23.2%) | 80 (18.8%) | - |
| Moderate, N (%) | 114 (26.1%) | 67 (15.8%) | * |
| Heavy, N (%) | 38 (8.7%) | 29 (6.8%) | - |
|
| |||
| Injury Severity Characteristics | |||
|
| |||
| Cause of Injury | 0.0010 c | ||
| Vehicular, N (%) | 234 (53.3%) | 206 (47.8%) | - |
| Falls, N (%) | 103 (23.5%) | 88 (20.4%) | - |
| Violence, N (%) | 44 (10.0%) | 85 (19.7%) | * |
| Sports / Other, N (%) | 58 (13.2%) | 52 (12.1%) | - |
|
| |||
| Associated SCI, N Yes (%) | 28 (6.4%) | 25 (5.8%) | 0.7217 c |
|
| |||
| PTA (days), Median (IQR) | 16 (5, 31) | 16 (2, 32.5) | 0.5017 b |
|
| |||
| Concurrent Functional Outcomes | |||
|
| |||
| FIM Motor at Follow-Up, Median (IQR) | 90 (88, 91) | 84 (78, 88) | < 0.0001 b |
|
| |||
| FIM Cognitive at Follow-Up, Median (IQR) | 33 (32, 34) | 30 (27, 32) | < 0.0001 b |
|
| |||
| DRS at Follow-Up, Median (IQR) | 1 (0, 2) | 4 (2, 5) | < 0.0001 b |
|
| |||
| GOSE at Follow-Up | < 0.0001 c | ||
| Severe Disability, N (%) | 45 (10.3%) | 160 (37.4%) | * |
| Moderate Disability, N (%) | 154 (35.4%) | 219 (51.2%) | * |
| Good Recovery, N (%) | 236 (54.3%) | 49 (11.4%) | * |
|
| |||
| Chronic Pain Characteristics | p-value | ||
|
| |||
| Pain Intensity, Mean (SD) | 3.2 (1.5) | 6.4 (1.6) | < 0.0001 a |
|
| |||
| Pain Location‡ | |||
| Back, N Yes (%) | 221 (50.2%) | 330 (76.6%) | < 0.0001 c |
| Legs or Feet, N Yes (%) | 192 (43.6%) | 319 (74.2%) | < 0.0001 c |
| Shoulder, N Yes (%) | 156 (35.5%) | 251 (58.2%) | < 0.0001 c |
| Head, N Yes (%) | 126 (28.6%) | 266 (61.7%) | < 0.0001 c |
| Neck, N Yes (%) | 134 (30.4%) | 232 (53.8%) | < 0.0001 c |
| Arms or Hands, N Yes (%) | 119 (27.0%) | 207 (48.0%) | < 0.0001 c |
| Hips, N Yes (%) | 89 (20.2%) | 205 (47.6%) | < 0.0001 c |
| Face or Jaw, N Yes (%) | 40 (9.1%) | 107 (24.9%) | < 0.0001 c |
| Pelvic Area or Groin, N Yes (%) | 34 (7.7%) | 111 (25.8%) | < 0.0001 c |
| Buttocks, N Yes (%) | 22 (5.0%) | 82 (19.0%) | < 0.0001 c |
| Widespread Pain or Fibromyalgia, N Yes (%) | 19 (4.3%) | 77 (17.9%) | < 0.0001 c |
| Chest, N Yes (%) | 22 (5.0%) | 80 (18.6%) | < 0.0001 c |
| Abdomen, N Yes (%) | 20 (4.5%) | 86 (20.0%) | < 0.0001 c |
|
| |||
| Frequency of Pain (Most Bothersome Location) | < 0.0001 c | ||
| Several Times a Week, N (%) | 161 (37.4%) | 64 (15.0%) | * |
| Daily, N (%) | 195 (45.2%) | 154 (36.2%) | * |
| Constant, N (%) | 75 (17.4%) | 208 (48.8%) | * |
|
| |||
| Neuropathic Pain Type | < 0.0001 c | ||
| Clinically Significant Positive, N (%) | 23 (5.6%) | 141 (34.7%) | * |
| Clinically Significant Negative, N (%) | 348 (85.3%) | 171 (42.1%) | * |
| Unclear, N (%) | 37 (9.1%) | 94 (23.2%) | * |
|
| |||
| Headache Type§ | < 0.0001 c | ||
| Migraine/Probable Migraine, N (%) | 83 (18.9%) | 235 (55.0%) | * |
| Other Headache, N (%) | 41 (9.4%) | 27 (6.3%) | - |
| No Head Pain, N (%) | 314 (71.7%) | 165 (38.6%) | * |
|
| |||
| Pain catastrophizing, Median (IQR) | 1 (0, 5) | 15 (9, 24) | < 0.0001 b |
|
| |||
| Treatment History Characteristics | |||
|
| |||
| Total Medical Services or Treatments, N (%) | 388 (88.4%) | 416 (97.4%) | < 0.0001 c |
| Medication, N (%) | 371 (84.7%) | 407 (95.5%) | < 0.0001 c |
| Injection, N (%) | 93 (21.2%) | 174 (40.7%) | < 0.0001 c |
| Surgery, N (%) | 62 (14.1%) | 90 (21.1%) | 0.0072 c |
| Implanted Device, N (%) | 5 (1.1%) | 21 (4.9%) | 0.0011 c |
| Non-Implanted Electrical Stimulator, N (%) | 92 (21.0%) | 120 (28.1%) | 0.0145 c |
|
| |||
| Total Exercise Therapies, N (%) | 336 (76.5%) | 360 (84.3%) | 0.0040 c |
| Physical Therapy, N (%) | 254 (58.0%) | 319 (74.7%) | < 0.0001 c |
| Pool or Aquatic Therapy, N (%) | 83 (18.9%) | 128 (30.0%) | 0.0002 c |
| Occupational Therapy, N (%) | 115 (26.3%) | 195 (45.8%) | < 0.0001 c |
| Yoga, N (%) | 93 (21.2%) | 88 (20.6%) | 0.8215 c |
| Tai Chi, N (%) | 18 (4.1%) | 25 (5.9%) | 0.2377 c |
| Home Exercise Program, N (%) | 264 (60.1%) | 263 (61.6%) | 0.6608 c |
|
| |||
| Total Psychological Services, N (%) | 133 (30.4%) | 218 (51.1%) | < 0.0001 c |
| Psychotherapy (e.g., CBT, ACT), N (%) | 38 (8.7%) | 107 (25.1%) | < 0.0001 c |
| Biofeedback, N (%) | 18 (4.1%) | 35 (8.2%) | 0.0122 c |
| Deep Breathing, N (%) | 107 (24.4%) | 171 (40.0%) | < 0.0001 c |
| Guided Imagery, N (%) | 29 (6.6%) | 66 (15.5%) | < 0.0001 c |
| Mindfulness Therapy, N (%) | 57 (13.0%) | 104 (24.4%) | < 0.0001 c |
| Hypnotherapy, N (%) | 12 (2.7%) | 16 (3.7%) | 0.4026 c |
|
| |||
| Total Complementary/Alternative Medicine, N (%) | 246 (56.3%) | 254 (59.5%) | 0.3421 c |
| Chiropractic, N (%) | 127 (29.1%) | 133 (31.1%) | 0.5039 c |
| Acupuncture, N (%) | 72 (16.5%) | 96 (22.5%) | 0.0257 c |
| Massage, N (%) | 202 (46.2%) | 199 (46.6%) | 0.9109 c |
|
| |||
| Comprehensive Pain Rehabilitation Program, N (%) | 41 (9.4%) | 74 (17.3%) | 0.0006 c |
SD = standard deviation; IQR = interquartile range;
†
Participants may self-report more than one race;
‡
Participants may self-report more than one pain location;
§
Headache Type was classified for those who reported head pain;
SCI = spinal cord injury; PTA = post-traumatic amnesia; FIM = Functional Independence Measure; DRS = Disability Rating Scale; GOS-E = Glasgow outcome scale – extended; BPI = Brief Pain Inventory; a: two-sample test; b: Wilcoxon rank-sum test; c: chi-square test; bold indicates statistically significant differences at α = 0.05;
*
indicates categorical levels with large (>2) cell chi-squares contributing to global differences