OBJECTIVES: Association between change in BMI over a 1-year period and the incidence of hypertension was examined based on real-world data in Japan. This was a sub-study of the main study which was reported previously (ISPOR Europe, 2015). METHODS: This was a retrospective study using a database composed of annual health checkup and claims data (MinaCare Co., Ltd.). A subset of subjects of the main study was selected for this study, which was those with at least 1 year of record prior to 2011, non-missing blood pressure (BP) and body mass index (BMI) values in both years (2011/Baseline, 2012), and aged≥20 years at the 2011 checkup. Diagnosis of hypertension was based on either SBP≥140mmHg/DBP≥90mmHg or prescription of antihypertensive medications based on physician diagnosis (ICD-10 codes I10-I15) within 1 year prior to checkup. RESULTS: A total of 251,043 subjects [Female 27.0%; Age 44.0/11.4 (mean/SD); diagnosis of hypertension (HTN) at baseline 18.7%] were analyzed. At baseline, the mean BMI across the age categories ranged between 20.7~22.3 for females and 22.7~24.1 for males. Mean percent change in BMI from 2011 to 2012 decreased with increasing age category for both sexes. Among those without HTN at baseline, the odds of HTN in 2012 increased with increasing BMI change categories for both sexes, after controlling for age, baseline BMI, baseline BP, and 2-way interactions. The association was stronger for males compared to females with the odds-ratio (95%CI) of 0.662 (0.607~0.721), 0.774 (0.719~0.832), 1.284 (1.211~1.362), 1.764 (1.651~1.885) for %BMI change category of ≤-1%, -1%~-0.5%, 0.5%~1%, ≥1%, respectively, where no change (-0.5%~+0.5%) was the reference. CONCLUSIONS: Incidence of HTN was positively associated with increasing level of change in BMI over the 1-year period, even after controlling for baseline BMI, BP and other factors. This suggests that controlling weight has impact on HTN even over a short period.