Productivity Loss Across Socioeconomic Groups Among Patients With Low Back Pain or Osteoarthritis: Estimates Using the Friction-Cost Approach in Norway

Our aim was to estimate the productivity loss (PL) among patients with low back pain (LBP) or osteoarthritis (OA) across socioeconomic groups, using the friction-cost approach (FCA). A total of 175,550 patients aged 18–65 years were included at their first diagnosis in specialty care between 2011 and 2016. PL was calculated for the year following diagnosis using individual wages, while adjusting for the friction length at 78 days per episode, a team production multiplier at 1.6, compensation mechanisms of 26.8