The statutory sickness fund AOK Lower Saxony developed a specific course program for a target group of up to 55-year old employees with common back pain in the early satge of chronification. Comparative evaluation of effects in study participants and controls was achieved by quality of life and performance data, i.e. days of sick leave (DSL). Medium and long-term change inquality of life (6 and 12 months after the course) was assessed by means of the SF-36 dimensions for cases and controls and compared in bivariate and multivariate test. 92 of 197 baseline participants (or 127 participants who completed the programme) and 483 controls were included in the medium term effect analysis. Significant medium and long-term net efffects could only be shown for pain dimensions. Anonymised DSL data for all 5409 insured persons who were initially selected as potiential participants for the regionally restricted course programme in the second quarter of 1997 were available for the period from 01-01-1996 to 30-06-1999. For controlling any selection bias and potential regional differences, the initial DSL trends of the 197 baseline course participants were compared with two control groups, namely other insured from the programme region and control regions. DSL trends in the three groups prior to the course program were identical. Subsequently DSL due to ICD-9 Codes 710-739 were reduced more substantially in course participants than in controls: 25.5 versus 33 or 32 days respectively. A covariance analysis model that also considered socio-economic factors and pre-intervention DSL levels yeilded a 14-day reduction in DSL (p value 0.023). This is a clear effect on DSL trends taht may be utilised for net savings for AOK. This is also the first proof of a backpain programme outside company settings taht permits net savings.