Interventions designed to reduce high health care costs for LBP should focus on patients with severe LBP and depressive comorbidity. Our results add to the economic understanding of LBP care and may give guidance for future actions on health care improvement and cost reduction.

Our study adds substantially to the knowledge of LBP-related case-mix in primary care. Information on differential health care needs may be inferred from our study, enabling decision makers to allocate resources more appropriately and to reduce costs.

Trends in cost-effectiveness are visible but need to be confirmed in future studies. Researchers performing cost-evaluation studies should test for baseline imbalances of health care utilization data instead of judging on the randomization success by reviewing non-cost parameters like clinical data alone.