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. (C) 2010 Elsevier Inc. All rights reserved.