Table 4.
Prognostic factors.
| Category | Prognostic factor | Categorical (1) or continuous variable (2) | Evaluated in the study as [ref. number] | Predictive value in overall | Study quality (n) | ||||
| Risk factor | Protective factor | Not significant statistically | Good | Fair | Poor | ||||
| Personal factors and medical history | Age | 1, 2 | 32,55 | 6 | 56,89,110,122,140 | IE | 7 | 1 | |
| Female sex | 1 | 110 | 32,55,89,122,140 | Risk | 5 | 1 | |||
| Body weight | 1, 2 | 59,63,97 | 32,56,89,122 | Risk | 7 | ||||
| Body height | 1 | 60 | Risk | 1 | |||||
| Body measures | 1 | 59 | Risk | 1 | |||||
| Diabetes | 1 | 57 | Risk | 1 | |||||
| Rheumatological event ≥1 | 1 | 32 | Risk | 1 | |||||
| Blood pressure | 1 | 46,62 | Protective | 1 | 1 | ||||
| Pulse pressure | 1 | 62 | Protective | 1 | |||||
| High cholesterol | 1 | 61 | NS | 1 | |||||
| High HDL cholesterol | 1 | 61 | NS | 1 | |||||
| High triglycerides | 1 | 61 | NS | 1 | |||||
| Smoking and nicotine dependence | 1 | 6,119 | 32,56 | Risk | 4 | ||||
| Alcohol dependence | 1 | 119 | NS | 1 | |||||
| Psychoactive substance dependence | 1 | 119 | NS | 1 | |||||
| Previous back surgery | 1 | 18 | NS | 1 | |||||
| Previous episode of LBP | 1 | 19,122 | Risk | 1 | 1 | ||||
| Low back injured in MVC | 1 | 99 | Risk | 1 | |||||
| Baseline disability before LBP | 2 | 18 | 122 | Risk | 2 | ||||
| Baseline general health poor | 2 | 18 | Risk | 1 | |||||
| Physical well-being | 1 | 140 | 89 | Protective | 2 | ||||
| Physical exercise | 1 | 97 | 32,56,89,110,122 | Protective | 5 | 1 | |||
| Level of education | 1 | 88,110 | NS | 2 | |||||
| Former productivity-related income | 1 | 32 | Risk | 1 | |||||
| Disability compensation | 1 | 55 | 18,19 | Risk | 2 | 1 | |||
| Occupational status | 1 | 19,32,140 | NS | 2 | 1 | ||||
| Number of different jobs held | 1 | 32 | Protective | 1 | |||||
| Back pain in parents | 1 | 110 | NS | 1 | |||||
| Symptom characteristics | |||||||||
| Pain intensity | 1, 2 | 54,55,122,140 | 89,110 | Risk | 4 | 1 | |||
| Pain duration | 1 | 55 | 89,110,140 | Risk | 3 | 1 | |||
| Pain radiation | 1 | 89,140 | NS | 2 | |||||
| Leg pain | 55,88 | NS | 1 | 1 | |||||
| To upper back | 88 | Risk | 1 | ||||||
| Multiple pain sites | 55 | NS | 1 | ||||||
| Pain requiring medication | 1 | 55,110,140 | NS | 2 | 1 | ||||
| Days of reduced activity because of LBP | 1 | 55 | Protective | 1 | |||||
| Affective pain | 1 | 89 | NS | 1 | |||||
| Pain interfering sleeping | 1 | 88 | NS | 1 | |||||
| Pain worse on standing | 1 | 19 | Risk | 1 | |||||
| Pain worse on lying | 1 | 19 | NS | 1 | |||||
| Disability and functional limitation | 1, 2 | 140 | 19,54,55,88,89,110 | Risk | 4 | 3 | |||
| Biomechanical factors | |||||||||
| Spinal mechanical load | 2 | 6 | NS | 1 | |||||
| Work-related back pain | 1 | 110 | Risk | 1 | |||||
| Particularly physical work | 1 | 56,58 | 110 | Risk | 2 | 1 | |||
| Physical intensity of work | 1 | ||||||||
| Moderate or vigorous | 83 | Risk | 1 | ||||||
| Vigorous only | 83 | Risk | 1 | ||||||
| Frequent rest breaks from work | 1 | 122 | NS | 1 | |||||
| Difficult working positions | 1 | 56,83,103 | 32 | Risk | 2 | 2 | |||
| Repetitive short movements | 1 | 103 | NS | 1 | |||||
| Carrying heavy loads/lifting at work | 1 | 32,58,83 | 56,103 | Risk | 3 | 2 | |||
| Working arms elevated | 1 | 103 | NS | 1 | |||||
| Bending and twisting trunk | 1 | 103 | NS | 1 | |||||
| Working kneeled/squatted | 1 | 103 | NS | 1 | |||||
| Vibration and jolts at work | 1 | 56 | 103 | Risk | 1 | 1 | |||
| Working with animals | 1 | 83 | NS | 1 | |||||
| Working tired | 1 | 83 | NS | 1 | |||||
| Psychological and psychosocial factors | |||||||||
| Good quality of life | 1 | 140 | Protective | 1 | |||||
| Mental well-being | 1 | 89 | NS | 1 | |||||
| Depression | 1, 2 | 55,119 | 32,89,110,140 | Risk | 5 | 1 | |||
| General anxiety | 1 | 110,119 | 55 | Risk | 2 | 1 | |||
| Post-traumatic stress disorder | 1 | 119 | Risk | 1 | |||||
| Antisocial personality disorder | 1 | 119 | NS | 1 | |||||
| Any psychiatric diagnosis | 1 | 119 | Risk | 1 | |||||
| Somatization | 1 | 88,89 | Risk | 1 | 1 | ||||
| Fear avoidance | 1 | ||||||||
| In general | 54 | NS | 1 | ||||||
| Of work activity | 89,110 | NS | 1 | 1 | |||||
| Of physical activity | 89,110 | NS | 1 | 1 | |||||
| Perceived risk of persistence | 1 | 55,88 | Risk | 1 | 1 | ||||
| Catastrophizing | 1 | 88 | 89 | Risk | 1 | 1 | |||
| Perceived stress | 1 | 88 | Risk | 1 | |||||
| Low tolerance of pain | 1 | 88 | 55 | Risk | 1 | 1 | |||
| Coping by ignoring pain | 1 | 88 | Risk | 1 | |||||
| Coping by music or TV watching | 1 | 88 | Protective | 1 | |||||
| Nonrecognition of work | 1 | 32 | Risk | 1 | |||||
| Job satisfaction/control | 1 | 89 | NS | 1 | |||||
| Work absenteeism | 1 | 89 | NS | 1 | |||||
| Support at work | 1 | 88,89 | 32 | Protective | 2 | 1 | |||
| Support at home | 89 | NS | 1 | ||||||
| High psychological job demands | 1 | 32,56,89,122 | NS | 4 | |||||
| Difficulty communicating | 1 | 32 | NS | 1 | |||||
Categorical variable measured yes/no or in larger categories, continuous variable measured by continuous scale. Reference number of the studies evaluating each prognostic factor presented in brackets. The number of studies (sum) presented in quality categories.
HDL, high-density lipoprotein; IE, inconclusive evidence; LBP, low back pain; MCV, motor vehicle collision; NS, not significant statistically; protective, statistically significant protective factor; risk, statistically significant risk factor.