Comparison of 2-year mortality according to obesity in stabilized patients with type 2 diabetes mellitus after acute myocardial infarction: results from the DIAMOND prospective cohort registry

Won et al. Cardiovasc Diabetol (2015) 14:141 DOI 10.1186/s12933-015-0305-1 ORIGINAL INVESTIGATION Open Access Comparison of 2‑year mortality according to obesity in stabilized patients with type 2 diabetes mellitus after acute myocardial infarction: results from the DIAMOND prospective cohort registry Ki‑Bum Won1, Seung‑Ho Hur1, Yun‑Kyeong Cho1, Hyuck‑Jun Yoon1, Chang‑Wook Nam1, Kwon‑Bae Kim1, Jang‑Ho Bae2, Dong‑Ju Choi3, Young‑Keun Ahn4, Jong‑Seon Park5, Hyo‑Soo Kim6*, Rak‑Kyeong Choi7, Donghoon Choi8, Joon‑Hong Kim9, Kyoo‑Rok Han10, Hun‑Sik Park11, So‑Yeon Choi12, Jung‑Han Yoon13, Hyeon‑Cheol Kwon14, Seung‑Un Rha15, Kyung‑Kuk Hwang16, Do‑Sun Lim17, Kyung‑Tae Jung18, Seok‑Kyu Oh19, Jae‑Hwan Lee20, Eun‑Seok Shin21 and Kee‑Sik Kim22 Abstract Background: After acute myocardial infarction (AMI), the replicated phenomenon of obesity paradox, i.e., obesity appearing to be associated with increased survival, has not been evaluated in stabilized (i.e., without clinical events within 1 month post AMI) Asian patients with diabetes mellitus (DM). Methods: Among 1192 patients in the DIabetic Acute Myocardial InfarctiON Disease (DIAMOND) Korean multicenter registry between April 2010 and June 2012, 2-year cardiac and all-cause death were compared according to obesity (body mass index ≥25 kg/m2) in 1125 stabilized DM patients. Results: Compared with non-obese DM patients (62 % of AMI patients), obese DM patients had: higher incidence of dyslipidemia (31 vs. 24 %, P < 0.01); lower incidence of chronic kidney disease (26 vs. 33 %) (P < 0.01); higher left ventricular ejection fraction after AMI (53 ± 11 vs. 50 ± 12 %, P < 0.001); and lower 2-year cardiac and all-cause death occurrence (0.7 vs. 3.6 % and 1.9 vs. 5.2 %, both P < 0.01) and cumulative incidence in Kaplan–Meier analysis (P < 0.005, respectively). Likewise, both univariate and multivariate Cox hazard regression analyses adjusted for the respective confounders showed that obesity was associated with decreased risk of both cardiac [HR, 0.18 (95 % CI 0.06–0.60), P = 0.005; and 0.24 (0.07–0.78), P = 0.018, respectively] and all-cause death [0.34 (0.16–0.73), P = 0.005; and 0.44 (0.20–0.95), P = 0.038]. Conclusions: In a Korean population of stabilized DM patients after AMI, non-obese patients appear to have higher cardiac and all-cause mortality compared with obese patients after adjusting for confounding factors. Keywords: Type 2 diabetes mellitus, Acute myocardial infarction, Obesity, Survival *Correspondence: 6 Division of Cardiology, Seoul National University Hospital, 28 Yeongeon‑dong, Chongno‑gu, Seoul 110‑744, South Korea Full list of author information is available at the end of the article © 2015 Won et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Won et al. Cardiovasc Diabetol (2015) 14:141 Background Obesity is strongly associated with an increased risk of numerous comorbidities and mortality in the general population [1–3]. In particular, obese subjects are more prone to be affected by cardiovascular (CV) events than non-obese subjects [4]. However, obesity appearing to be associated with improved survival has been reported after major CV events such as acute myocardial infarction (AMI) [5–9]. It is well established that diabetes mellitus (DM) is a major risk factor for CV morbidity and mortality [10, 11]. Previous studies have reported that diabetic patients have an increased risk for mortality after AMI [12, 13]. However, there is a paucity of data on the association between obesity and mortality in diabetic patients after the event of AMI; identifying this association may be more important in the Asian population because of the explicitly different features of DM in Asia [14–16]. In addition, it is necessary to evaluate this association in stabilized (i.e., without clinical events within 1 month) patients after AMI considering that it is difficult to identify the individual impact of clinical factors on early-term events after AMI [17]. Thus, we evaluated the association between obesity and 2-year mortality in stabilized diabetic patients after AMI in the Korean population. Methods Subjects and study design This is a prospective, multicenter, observational study of clinical outcomes following AMI in patients with type 2 DM included in the DIabetic Acute Myocardial InfarctiON Disease (DIAMOND) registry in Korea between April 2010 and June 2012. Initially, 1192 consecutive patients with type 2 DM who presented with ST-elevation myocardial infarction (STEMI) or non ST-elevation myocardial infarction (NSTEMI) were enrolled from 22 university or tertiary hospitals that voluntarily participated in this study and were evenly distributed throughout South Korea. All participants had: (a) age ≥45 years; (b) documented STEMI or NSTEMI by an elevated creatine kinase-MB fraction (CK-MB) (exceeding 3 times upper limit of normal) and cardiac troponin-I level (exceeding upper normal limit); and (c) angiographically confirmed significant coronary stenosis (≥50 % luminal stenosis) with intracoronary filling defect or haziness suggesting coronary thrombus/vulnerable plaque, or coronary spasm induced acute myocardial infarction defined by an elevated cardiac enzymes without significant stenosis. Type 2 DM was diagnosed by fasting plasma glucose level on two separate occasions ≥126 mg/dL or a random plasma glucose level ≥200 mg/dL or 2-h plasma glucose post 75 g dextrose load done on two separate occasions ≥200 mg/dL, or previously diagnosed DM by taking Page 2 of 8 oral hypoglycemic agents or using insulin. The duration of DM was defined as the time elapsed since a physician diagnosed the diabetic condition. BMI was calculated as weight (kg)/height (m2), and obesity was defined as a BMI of ≥25 kg/m2. Stabilized patients with AMI were defined as those who did not have any clinical events within 1 month after the initial presentation of AMI. Among these patients, 67 patients who died in hospital during admission or did not undergo follow-up within 1 month after discharge were excluded from the present study. Finally, 1125 diabetic patients with AMI who did not have any events within 1 month were enrolled for evaluation of cardiac and all-cause mortality according to obesity status. Percutaneous coronary intervention (PCI) was performed by stenting (stent type and glycoprotein IIb/IIIa receptor blocker use at operator’s discretion) using standard technique via femoral or radial approach after a loa (...truncated)