Participation in health check-ups and mortality using propensity score matched cohort analyses

Objective: All Japanese aged ≥40 years are eligible for free annual health check-ups including blood pressure and cholesterol measurements. It is well known that health check-up screenees are more likely to have healthy lifestyles and better health conditions than non-screenees. Therefore, controlling these factors is required to investigate whether screenees have a lower mortality risk than non-screenees independent of their lifestyles or health conditions. Methods: We followed 48,775 Japanese National Health Insurance beneficiaries aged 40-79 years since 1994 for 11 years. We used Cox proportional hazard models adjusted for possible confounding factors. We also performed propensity for use of the health check-up matched cohort analyses. Results: Compared to non-screenees, multiple-adjusted hazard ratios (95% confidence intervals) for all-cause and cardiovascular disease mortality among screenees were 0.74 (0.62-0.88) and 0.65 (0.44-0.95) for men and 0.69 (0.52-0.91) and 0.61 (0.36-1.04) for women, respectively. These relations were also observed when we used propensity matched cohort analyses. Conclusion: This is the first study to show that mortality rates are lower among screenees than non-screenees in Japanese health check-ups when propensity matched cohort analyses were used for adjusting confounding factors. Further prospective studies, including randomized controlled trials, are required to confirm whether screening lowers mortality.