Consistent evidence was found for the predictive value of pain intensity ( more pain-- > worse outcome ) , several work-related parameters ( e.g. , high satisfaction-- > better outcome ) , and coping style ( less active coping-- > better outcome ) .
Other sociodemographic and physical variables consistently lacked predictive value .
No consistent evidence was found for other psychological variables .
CONCLUSIONS It is impossible to define a generic set of predictors of outcome of multidisciplinary rehabilitation and back schools for patients with chronic low back pain because the review ed studies were descriptive or exploratory in nature , and most predictors were only studied once .
Nevertheless , for several predictors , consistent evidence was found .
OBJECTIVE To determine predictors of outcome of multidisciplinary rehabilitation-or back school treatment  for patients with chronic low back pain .
SUMMARY OF BACKGROUND DATA Numerous review s have been performed to gain insight into which patients benefit from which treatment .
However , no review has systematic ally focused on predictors from multiple domains ( i.e. , sociodemographic , physical , and psychological ) , or on treatment outcome measured as activity limitation or participation restriction .
Problems in defining cutoff points of continuous prognostic factors: example of tumor thickness in primary cutaneous melanoma.
Continuous prognostic factors are often categorized by defining optimized cutoff points . One component of criticism of this approach is the problem of multiple testing that leads to an overestimation of the true prognostic impact of the variable . The present study focuses on another crucial point by investigating the dependence of optimized cutoff points on the observed distribution of the continuous variable . The continuous variable investigated was the vertical tumor thickness according to Breslow , which is known to be the most important prognostic factor in primary melanoma . Based on the data of 5093 patients , stratified r and om sample s were drawn out of six artificially created distributions of tumor thickness . For each of these sample s , Cox models were calculated to explore optimized cutoff points for tumor thickness together with other prognostic variables . The optimized cutoff points for tumour thickness varied considerably with the underlying distribution . Even in sample s from the same distribution , the range of cutoff points was amazingly broad and , for some of the distributions , covered the whole region of possible values . The results of the present study demonstrate that optimized cutoff points are extremely data dependent and vary notably even if prerequisites are constant . Therefore , if the classification of a continuous prognostic factor is necessary , it should not be based on the results of one single study , but on consensus discussion s including the findings of several investigations
Consistent evidence was found for the predictive value of pain intensity ( more pain-- > worse outcome ) , several work-related parameters ( e.g. , high satisfaction-- > better outcome ) , and coping style ( less active coping-- > better outcome ) .
Other sociodemographic and physical variables consistently lacked predictive value .
No consistent evidence was found for other psychological variables .
CONCLUSIONS It is impossible to define a generic set of predictors of outcome of multidisciplinary rehabilitation and back schools for patients with chronic low back pain because the review ed studies were descriptive or exploratory in nature , and most predictors were only studied once .
Nevertheless , for several predictors , consistent evidence was found .
OBJECTIVE To determine predictors of outcome of multidisciplinary rehabilitation-or back school treatment  for patients with chronic low back pain .
SUMMARY OF BACKGROUND DATA Numerous review s have been performed to gain insight into which patients benefit from which treatment .
However , no review has systematic ally focused on predictors from multiple domains ( i.e. , sociodemographic , physical , and psychological ) , or on treatment outcome measured as activity limitation or participation restriction .