Table 5.
Comparison of demographic characteristics health-related outcomes between Class 1 and Class 2 participants.
| Variable | Total (n = 172) | Class 1 (n = 66) | Class 2 (n = 106) | P value | FDR* |
|---|---|---|---|---|---|
| Demographics | |||||
| Gender, n (%) | |||||
| Female | 108 (62.7) | 35 (53.0) | 73 (68.8) | .036 | 0.094 |
| Male | 64 (37.2) | 31 (46.9) | 33 (31.1) | ||
| Age, years, mean (SD) | 58.7 (10.6) | 61.5 (11.0) | 57.0 (10.1) | .009 | 0.036 |
| Ethnicity, n (%) | |||||
| Hispanic or Latino | 8 (4.8) | 2 (3.2) | 6 (5.8) | .451 | 0.0.601 |
| Not Hispanic or Latino | 157 (95.1) | 60 (96.8) | 97 (94.2) | ||
| Race, n (%) | |||||
| Black/African American | 9 (5.4) | 3 (4.7) | 6 (5.8) | .392 | 0.565 |
| White | 150 (90.4) | 59 (93.6) | 91 (88.3) | ||
| Other | 7 (4.2) | 1 (1.5) | 6 (5.8) | ||
| Education, n (%) | |||||
| No high school diploma | 3 (1.7) | 2 (3.0) | 1 (.94) | .743 | 0.787 |
| High school graduate or GED | 19 (11.0) | 8 (12.1) | 11 (10.4) | ||
| Some college, no degree | 34 (19.7) | 14 (21.2) | 20 (18.8) | ||
| Occupational/technical/vocational program | 9 (5.2) | 2 (3.0) | 7 (6.6) | ||
| Associate degree: academic program | 27 (15.7) | 7 (10.6) | 20 (18.8) | ||
| Bachelor’s degree | 41 (23.8) | 16 (24.2) | 25 (23.5) | ||
| Master’s degree | 29 (16.8) | 13 (19.7) | 16 (15.1) | ||
| Professional school degree | 4 (2.3) | 1 (1.5) | 3 (2.8) | ||
| Doctoral degree | 6 (3.5) | 3 (4.5) | 3 (2.8) | ||
| Employment, n (%) | |||||
| Working now | 32 (18.6) | 11 (16.6) | 21 (19.8) | .748 | 0.787 |
| Unemployed | 5 (2.9) | 2 (3.0) | 3 (2.8) | ||
| Disabled | 27 (15.57) | 9 (13.6) | 18 (16.9) | ||
| Disabled due to back pain | 61 (35.4) | 22 (33.3) | 39 (36.7) | ||
| Retired | 36 (20.9) | 18 (27.2) | 18 (16.9) | ||
| Other (includes Other, Sick or maternity leave, Student, Keeping house) | 11 (6.4) | 4 (6.0) | 7 (6.6) | ||
| Back pain history and perception characteristics (NIH MD) | |||||
| CLBP duration, n (%) | |||||
| 3–6 months | 1 (0.6) | 0 (0.0) | 1 (.94) | .717 | 0.787 |
| 6 months–1 year | 4 (2.3) | 2 (3.0) | 2 (1.8) | ||
| 1–5 years | 25 (14.5) | 8 (12.1) | 17 (16.0) | ||
| >5 years | 142 (82.6) | 56 (84.5) | 86 (81.1) | ||
| Prior treatments for back pain, Yes, n (%) | |||||
| Injections (e.g., epidural steroid, facet) | 140 (81.4) | 50 (75.7) | 90 (84.9) | .188 | 0.358 |
| Exercise therapy (physical therapy) | 160 (93.0) | 61 (92.4) | 99 (93.4) | .402 | 0.565 |
| Psychological counseling | 62 (36.0) | 24 (36.4) | 38 (35.8) | .966 | 0.966 |
| History of a low back operation, n (%) | |||||
| Yes | 51 (59.3) | 20 (54.0) | 31 (63.2) | .682 | 0.787 |
| One operation | 32 (18.6) | 16 (24.2) | 16 (15.1) | ||
| More than one operation | 54 (31.4) | 21 (31.8) | 33 (31.1) | .376 | 0.563 |
| No | 85 (49.4) | 29 (43.9) | 56 (52.8) | ||
| I feel that my back pain is terrible and it’s never going to get any better…, n (%) | |||||
| Agree | 82 (47.6) | 28 (42.4) | 54 (50.9) | .038 | 0.094 |
| Disagree | 81 (47.1) | 31 (46.9) | 50 (47.2) | ||
| It’s not really safe for a person with my back problem to be physically active…, n (%) | |||||
| Agree | 60 (34.8) | 21 (31.8) | 39 (36.7) | .654 | 0.787 |
| Disagree | 108 (62.7) | 44 (66.6) | 64 (60.4) | ||
| Clinical characteristics | |||||
| Average pain severity (BPI, 0–10 score), mean (SD) | 5.9 (1.5) | 5.7 (1.6) | 6.0 (1.4) | .126 | 0.252 |
| Function | |||||
| Pain interference (BPI, 0–10 score range), mean (SD) | 6.4 (1.9) | 5.9 (2.0) | 6.7 (1.7) | .012 | 0.042 |
| Back pain-related disability (ODI, 0–100 score range), mean (SD) | 47.4 (13.6) | 46.1 (14.5) | 49.5 (12.9) | .109 | 0.236 |
| Health-related quality of life (SF-12) | |||||
| Physical health composite score (0–100 range), mean (SD) | 28.2 (8.6) | 27.9 (9.2) | 28.3 (8.3) | .723 | 0.787 |
| Mental health composite score (0–100 range), mean (SD) | 43.7 (11.4) | 48.1 (10.5) | 40.9 (11.1) | <.001 | 0.005 |
| Daily dose of prescribed opioids, past 14 days (TLFB, morphine-equivalent mg/day), average daily dose, mean (SD) | 196.2 (786.1) | 227.7 (819.3) | 176.6 (768.1) | .679 | 0.787 |
| Opioid misuse risk (COMM), total score (0-35 range), mean (SD) | 8.9 (6.2) | 6.8 (4.6) | 10.3 (6.6) | <.001 | 0.005 |
| Sleep quality (NIH MD), total score (4-19 range), mean (SD) | 10.1 (3.8) | 10.6 (3.7) | 9.8 (3.8) | .193 | 0.358 |
| Negative affect (HADS), total score (1-36 range), mean (SD) | 16.2 (7.7) | 13.7 (7.8) | 17.7 (7.2) | <.001 | 0.005 |
| Pain catastrophizing (PCS), total score (0-50 range), mean (SD) | 19.4 (11.5) | 16.6 (10.5) | 21.2 (11.8) | .010 | 0.037 |
| Loneliness (UCLA LS), total score (3-9 range), mean (SD) | 5.7 (2.1) | 5.3 (2.2) | 6.0 (2.1) | .034 | 0.093 |
| Feeling loved (FLI) | |||||
| Feeling loved by others (0-100 score range), mean (SD) | 80.1 (21.7) | 82.0 (21.0) | 78.9 (22.1) | .362 | 0.563 |
| Loving yourself (0-100 score range), mean (SD) | 69.7 (27.8) | 75.1 (23.6) | 66.3 (29.8) | .049 | 0.116 |
| Healthcare utilization and productivity characteristics (past 6 months) | |||||
| Hospitalized, Yes, # (%) | 27 (15.8) | 6 (9.2) | 21 (19.8) | .118 | 0.245 |
| Number of nights hospitalized (n = 27), mean (SD) | 10.5 (18.7) | 8.8 (14.0) | 11.0 (20.1) | .808 | 0.824 |
| ED visit, Yes, # (%) | 47 (27.5) | 14 (21.5) | 33 (31.1) | .252 | 0.437 |
| Number of ED visits (n = 47), mean (SD) | 2.5 (3.1) | 1.6 (0.9) | 3.0 (3.6) | .218 | 0.391 |
| Clinic visit (“regular” care, urgent care), Yes, # (%) | 148 (87.5) | 55 (84.4) | 93 (89.4) | .336 | 0.549 |
| Number of clinic visits (n = 148), mean (SD) | 7.6 (9.6) | 6.6 (6.0) | 8.0 (11.1) | .379 | 0.563 |
| Mental health care visit, Yes, # (%) | 61 (35.9) | 19 (27.7) | 42 (40.4) | .093 | 0.210 |
| Number of mental health care visits (n = 61), mean (SD) | 9.7 (8.5) | 10.8 (10.3) | 8.9 (7.5) | .434 | 0.594 |
| Addiction care visit, Yes, # (%) | 6 (3.5) | 3 (4.6) | 3 (2.8) | .546 | 0.693 |
| Number of addiction care visits (n = 6), number, mean (SD) | 11.8 (20.3) | 3.0 (2.6) | 20.7 (28.0) | .338 | 0.549 |
| Whole workdays missed (among those “working now”), Yes, # (%) | 35 (27.3) | 12 (18.5) | 23 (21.7) | .469 | 0.610 |
| Number of whole workdays missed (n = 35), mean (SD) | 47.2 (63.4) | 54.7 (66.7) | 43.3 (62.7) | .623 | 0.771 |
| Chores (school/house work) missed, Yes, # (%) | 121 (78.5) | 41 (61.5) | 80 (75.5) | .026 | 0.075 |
| Number of whole days of chores missed (n = 121), mean (SD) | 45.1 (49.8) | 44.7 (56.3) | 44.5 (46.6) | .757 | 0.787 |
BPI = Brief Pain Inventory, CLBP = Chronic Low Back Pain, COMM = Current Opioid Misuse Measure, ED = Emergency Department, FDR = False Discovery Rate, FLI = Feeling Loved Instrument, HADS = Hospital Anxiety Depression Scale, HCUPS = HealthCare Utilization and Productivity Survey, NIH MD = NIH Minimal Data Set, PCS = Pain Catastrophizing Scale, SF-12 = 12-Item Short Form Health Survey, TLFB = Timeline Followback, UCLA LS = UCLA Loneliness Scale.
*
False Discovery Rate (P value corrected for multiple comparisons).