Despite a decade of historical debate and the recent rebuttal regarding “diabetes mellitus (DM) as a CAD risk equivalent”, few studies have evaluated the impact of prediabetes (preDM) separately. Thus, it is still possible that the impact of DM has been underestimated unless preDM is excluded from the nondiabetic category and independently assessed along with normal glucose tolerance (NGT) and DM. To clarify the independent risk of NGT, preDM and DM with and without prior CAD for incident CAD, we analyzed data using a nationwide claim-based database that included 138,162 men (NGT 78,230; preDM 45,610; DM 14,322) aged 18-72 y in Japan. Multivariate Cox analysis showed that the impact of preDM on CAD was modest compared to DM even with prior CAD (Model 1, Table) whereas prior CAD confers a 5-8-fold excess risk for CAD regardless of GTS (Model 2, Table). The hazard ratio (HR) of CAD in NGT individuals with prior CAD was much higher than in DM individuals without prior CAD (HR 3.08(95% CI 2.08-4.54)). The HR in those with both DM and prior CAD was 15.7(11.8-21.0) compared to NGT without prior CAD. In conclusion, DM alone is not prior CAD risk-equivalent even if the influence of preDM is eliminated. Prior CAD confers a far higher risk for subsequent CAD regardless of GTS. Necessity of intense intervention for the secondary prevention of CAD is implied considering the enormously high risk in those with both DM and prior CAD. Disclosure M. Kitazawa: None. K. Fujihara: None. M. Harada: None. M. Ishizawa: None. M. Yamamoto: None. M. Kaneko: None. T. Osawa: None. T. Yamada: None. Y. Matsubayashi: None. H. Sone: Research Support; Self; Novo Nordisk Inc., Eli Lilly and Company, MSD K.K., Chugai Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Development Center Asia, Pte. Ltd., Daiichi Sankyo Company, Limited, Ono Pharmaceutical Co., Ltd., Kyowa Hakko Kirin Co., Ltd., Sanofi, Kowa Pharmaceuticals America, Inc., Eisai Inc..