Table 3.
Hierarchical multivariate analysis of demographic, medical and psychological variables in relation to BASFI
| Step | Independent variable | Mean difference | R-square (%)* | P value+ |
|---|---|---|---|---|
| 1 | Demographic variables | 21.0 * | < 0.001+ | |
| Age | 0.54 | < 0.001 | ||
| Employment | -13.58 | < 0.001 | ||
| Gender | -4.68 | 0.122 | ||
| Marital | 2.15 | 0.491 | ||
| Education | -3.80 | 0.001 | ||
| Student | 2.75 | 0.669 | ||
| Ethnicity | -4.38 | 0.259 | ||
| 2 | Medical variables | 32.0* | < 0.001+ | |
| Current tobacco use | 9.12 | 0.099 | ||
| NSAID therapy | 6.56 | 0.021 | ||
| BASRI (range 1.5 -- 16) | 0.75 | 0.134 | ||
| Biologic therapy | 4.96 | 0.052 | ||
| Number of medical co-morbidities | 2.08 | 0.19 | ||
| Erythrocyte sedimentation rate | 0.36 | 0.001 | ||
| Disease duration | 0.00 | 0.86 | ||
| Days of general exercise per week | -1.5 | 0.036 | ||
| Back exercise | -6.35 | 0.08 | ||
| Physical therapy | 12.65 | 0.024 | ||
| 3 | Psychological variables | 56.3* | < 0.001+ | |
| Arthritis internality (6-36) | -0.54 | 0.048 | ||
| Arthritis helplessness (5-25) | 1.14 | 0.004 | ||
| Resilience coping (BRCS) (0-20) | 0.32 | 0.507 | ||
| Depression (PHQ-9) (0-27) | 0.90 | 0.013 | ||
| Active coping (7-35) | -0.12 | 0.703 | ||
| Passive coping (11-55) | 0.68 | 0.006 |
*Overall R-square (%) after the addition of each conceptual block. +Overall P value after the addition of each block. BASFI = Bath Ankylosing Spondylitis Functional Index; BASRI = Bath Ankylosing Spondylitis Radiographic Index; BRCS = Brief Resilient Coping Scale; PHQ = Patient Health Questionnaire.