Impact of diabetes among revascularized patients in Japan and the U.S.
OBJECTIVE
Approximately 25% of patients who undergo percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) have diabetes, and the diagnosis of diabetes roughly doubles the mortality risk associated with coronary artery disease. However, the impact of diabetes may differ according to ethnicity. Our objective was to examine the impact of diabetes on long-term survival among U.S. and Japanese patients who underwent PCI or CABG.


METHODS
For the current analysis, we included 8,871 patients from a Japanese multicenter registry (Coronary Revascularization Demonstrating Outcome database in Kyoto; median follow-up 3.5 years; interquartile range [IQR] 2.6-4.3) and 7,229 patients from a U.S. multipractice registry (Texas Heart Institute Research Database; median follow-up 5.2 years; IQR 3.8-6.5).


RESULTS
Diabetes was more prevalent among Japanese than U.S. patients (39.2 vs. 31.0%; P < 0.001). However, after revascularization, long-term all-cause mortality was lower in diabetic Japanese patients than in diabetic U.S. patients (85.4 vs. 82.2%; log-rank test P = 0.009), whereas it was similar in nondiabetic Japanese and U.S. patients (89.1 vs. 89.5%; P = 0.50). The national difference in crude mortality was also significant among insulin-using patients with diabetes (80.8 vs. 74.9%; P = 0.023). When long-term mortality was adjusted for known predictors, U.S. location was associated with greater long-term mortality risk than Japanese location among nondiabetic patients (hazard ratio 1.58 [95% CI 1.32-1.88]; P < 0.001) and, especially, diabetic patients (1.88 [1.54-2.30]; P < 0.001).


CONCLUSIONS
Although diabetes was less prevalent in U.S. patients than in Japanese patients, U.S. patients had higher overall long-term mortality risk. This difference was more pronounced in diabetic patients.
Division of Cardiology, Department of Medicine, Keio University School of Medicine, Tokyo, Japan. kohsaka@cpnet.med.keio.ac.jp
Shun
S
Kohsaka
Masashi
M
Goto
Toshiyuki
T
Nagai
Vei-Vei
VV
Lee
MacArthur
M
Elayda
Yutaka
Y
Furukawa
Masanori
M
Fukushima
Masashi
M
Komeda
Ryuzo
R
Sakata
Mitsuru
M
Ohsugi
Keiichi
K
Fukuda
James M
JM
Wilson
Toru
T
Kita
Takeshi
T
Kimura
D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000401:mortality; D001026:Coronary Artery Bypass / Q000401:mortality; D003920:Diabetes Mellitus / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D014481:United States