“…Various patient-populations with various severeness of symptoms have been studied, various content of rehabilitation programs have been used, and the studies have been performed in various health care settings in specialized and in primary care [20,23,[40][41][42][43][44][45][46][47][48][49][50][51]. Moreover, the previous literature shows somewhat conficting results of that; no strong predictive baseline variables exist to predict successful outcome [20-23, 42, 46, 47], and worse baseline status can be associated with improved outcome after rehabilitation [23,40,42,[46][47][48], but also that poor pretreatment physical and psychological functioning at the baseline can have a negative prognosis [20]. Also, in previous studies, various outcomes and predictive baseline variables are used [20,23,[40][41][42][43][44][45][46][47][48][49][50][51].…”