Reducing the prevalence of low-back pain by reducing the prevalence of psychological distress: Evidence from a natural experiment and implications for health care providers

OBJECTIVE: To determine whether exogenously reduced psychological distress reduces reported low‐back pain (LBP) and is associated with reduced medical visits for LBP. DATA SOURCES: National Health Interview Survey, National Ambulatory Medical Care Survey, National Hospital Ambulatory Medical Care Survey, 1998‐2004. STUDY DESIGN: We estimate a fuzzy regression discontinuity model in which a discontinuity in the prevalence of psychological distress is identified by exogenous national events. We examine whether this discontinuity induced a corresponding discontinuity in the prevalence of LBP. We additionally estimate a regression discontinuity model to determine associated changes in medical visits with LBP as the primary complaint. PRINCIPAL FINDINGS: The prevalence of LBP was discontinuously reduced by one‐fifth due to the exogenous national discontinuous reduction in psychological distress. This discontinuity in LBP cannot be explained by discontinuities in employment, insurance, injuries/poisoning, general health status, or other factors. We find an associated three‐fifth discontinuous reduction in medical visits with LBP as the primary complaint. CONCLUSIONS: On a monthly basis, 2.1 million (P