Table 2 Description of workers assigned to each of the four clusters.
| Cluster 1 | Cluster 2 | Cluster 3 | Cluster 4 | p Value | |
|---|---|---|---|---|---|
| Continuous high pain | Fluctuating pain | Moderate reduction in pain | Large reduction in pain | ||
| Size, n | 291 (42.9%) | 222 (32.7%) | 81 (11.9%) | 84 (12.4%) | |
| Age | 39.58 (10.99) | 36.68 (10.24) | 36.31 (13.60) | 36.95 (11.05) | 0.02* |
| Gender (% male) | 138 (47.4%) | 108 (48.7%) | 35 (43.2%) | 46 (54.8%) | 0.55** |
| Education | |||||
| <High school | 119 (41.3%) | 61 (27.7%) | 32 (40.0%) | 37 (44.1%) | |
| High school | 120 (41.7%) | 104 (47.3%) | 38 (47.5%) | 27 (32.1%) | |
| Advanced degree | 49 (17.0%) | 55 (25.0%) | 10 (12.5%) | 20 (23.8%) | 0.01** |
| Weekly earnings | 553.94 (245.55) | 567.80 (248.18) | 476.33 (227.62) | 583.81 (266.73) | 0.04* |
| Past history of back injury (% yes) | 105 (36.8%) | 52 (23.6%) | 23 (28.8%) | 19 (22.9%) | 0.01** |
| Other health conditions (% yes) | 48 (16.5%) | 22 (9.9%) | 4 (4.9%) | 6 (7.1%) | 0.02*** |
*Based on ANOVA.
**Based on χ2 test.
***Based on Fisher's exact test.