| BackgroundAcute myocardial infarction (AMI) is a high mortality disease, which severely threatens human’s health and survival. During 2004 to 2012, medical costs of AMI in hospital increased 25% per year in China, bringing enormous economic burden. It is reported that antiplatelet therapy, beta blocker, ACEI, statin and interventional therapy effectively decrease mortality in AMI patients. However, mortality of AMI is still in a high level and has a trend to increase in China. Studies of influencing factors on therapeutic efficacy in AMI are in a smaller amount at present. Metabolic syndrome (MS) starts in metabolic abnormities and integrates several cardiovascular risk factors, main clinical outcomes of which are cardiovascular injuries. With changes of life style and eating habits, prevalence of MS increases yearly. Population aging in China is growing severely. Aging and increased population capacity will lead to an increase of cardiovascular diseases by a half at least in the future 20 years. And prevalence of MS in the elderly is high and increases in a high speed. Whether MS or older age will lead to more cardiovascular events and more medial costs of AMI patients in hospital? How MS components influence prognosis and medical costs of AMI patients? And if there is an interaction between age and MS? According to these questions, we designed this study.Objectives(1) To examine impact of MS and its components on cardiovascular events and medical costs of AMI in hospital.(2) To investigate impact of age on cardiovascular events and medical costs of AMI in hospital and to study the interaction between age and MS.(3) To analysis predict factors of cardiovascular events and medical costs of AMI patients and older AMI patients in hospital.Subjects and methodsIn this study we included 997 AMI patients. Information of case files was collected, including admission number, age, height, weight, diagnosis at admission and at discharge, hospital stay, hospitalization costs, smoking history, past history, family history, chemical examination, coronary arteriography results, echocardiography results, cardiovascular events and drug usage. According to Chinese Diabetes Society (CDS) diagnostic criteria of MS, we grouped all AMI patients in this study. We divided AMI patients into 2 groups according to whether with MS:AMI patients without MS and AMI patients with MS. To study impact of MS components on AMI, we grouped AMI patients according to whether with overweight, high glucose, hypertension or dyslipidemia. According to number of MS components, we separated AMI patients to 3 groups:non-MS-component AMI patients, with MS component but without MS (1-2 MS components) AMI patients, MS AMI patients. To study interaction between age and MS, we grouped AMI patients according to whether with older age or MS. We defined older people aged 65 or older. Thus there were 4 groups: young non-MS AMI patients, young MS AMI patients, older non-MS AMI patientsand older MS AMI patients. Cardiovascular events and medical costs were compared using statistical methods. To select risk factors of cardiovascular events and medical costs using regression methods. To calculate cost-effective ratio (CER) and incremental cost-effective ratio (ICER).Results(1) Sex and age composition of AMI patients. There were 70% males and 30% females in AMI at admission during 2011-2013 in Qilu Hospital of Shandong University. AMI happened mainly in 45-85 years old. AMI happened in males aged 55-64 years mostly. From 55, female AMI happened much more, mostly aged 75-84 years. With age increasing, ratio of females to males AMI patients gradually increased.(2) Prevalence of MS and its components in AMI patients. Prevalence of MS in AMI was 39%. Prevalence of BMI leveled in 25 and upper in AMI was 25%. Prevalence of high FBG in AMI was 53%. Prevalence of hypertension in AMI was 66%. Prevalence of high TG in AMI was 30%. Prevalence of low HDL in AMI was 22%.(3) Comparison of basic clinical data and treatment of AMI patients. Compared with non-MS AMI patients, AMI patients with MS had higher SBP, DBP, heart rate, Cho, TQ LDL, serum glucose, BUN, Cr, UA, urine protein, hypertension family history, diabetes family history and coronary heart disease family history (P<0.05-0.001), but lower male ratio, age, HDL, LDH, CK (P< 0.05-0.001). Compared with non-MS AMI patients, AMI patients with MS had similar usage of PCI, twice revascularization, aspirin, ACEI and diuretics (P>0.05), and higher usage of ADP blocker, beta blocker, ARB, statin and CCB.(4) Impact of MS and its components on cardiovascular events of AMI patients in hospital. Compared with non-MS AMI patients, AMI patients with MS had a trend of increased acute heart failure, atrial arrhythmia, ventricular arrhythmia, death and decreased event-free survival, but the differences didn’t reach a statistical significance (P>0.05). Compared with non-MS-component AMI patients, AMI patients with 1-2 MS components had a decreased event-free survival (P<0.05). Similarly, compared with non-MS-component AMI patients, AMI patients with MS had a decreased event-free survival (P<0.05). However, compared with AMI patients with 1-2 MS components, AMI patients with MS had a trend of increased atrial arrhythmia, ventricular arrhythmia, death and decreased event-free survival, but the differences didn’t reach a statistical significance (P>0.05). AMI patients with high FBG had a significantly higher rate of acute heart failure, atrial arrhythmia, ventricular arrhythmia and a significantly lower rate of event-free survival (P<0.05). AMI patients with hypertension had a higher rate of acute heart failure, atrial arrhythmia and a lower rate of event-free survival (P<0.05). AMI patients with low HDL had a significantly higher mortality (P<0.05).(5) Impact of MS and its components on duration and medical costs of AMI patients in hospital. Medical costs of AMI patients in hospital was mainly composed of medical treatment costs (57%) and medication costs (34%). Compared with non-MS AMI patients, AMI patients with MS had a trend of higher total medical costs, daily medical costs, medical treatment costs, chemical examination cost, but the differences didn’t reach a statistical significance (P>0.05). Compared with non-MS-component AMI patients, AMI patients with 1-2 MS components had higher daily medical costs (5.03±0.25 vs.4.15±0.21, P<0.05). Similarly, compared with non-MS-component AMI patients, AMI patients with MS had higher daily medical costs (5.03±0.26 vs. 4.15±0.21, P<0.05). AMI patients with BMI≥25 had higher total medical costs (53.63±1.64 vs.45.75±1.53, P<0.05), daily medical costs (5.57±0.25 vs.4.70±0.23, P <0.05) and medical treatment costs (27.57±1.46 vs.20.73±1.32, P<0.05). AMI patients with higher FBG had longer hospital stay (12.51±0.28 vs.11.48±0.25, P< 0.05), higher medication costs (13.59±0.40 vs.11.97±0.38, P<0.05), chemical examination costs (2.07±0.06 vs.1.75±0.04, P<0.05). AMI patients with hypertension had lower medical treatment costs (21.56±1.08 vs.25.17±1.43, P<0.05). AMI patients with high TG had shorter hospital stay (11.07±0.30 vs.12.48±0.24, P<0.05) and higher daily medical costs (5.72±0.32 vs.4.53±0.19, P<0.05), medical treatment costs (26.43±1.65 vs.21.24±1.02, P<0.05), and lower medication costs (12.01±0.44 vs. 13.25±0.35, P<0.05), chemical examination costs (1.76±0.05 vs.2.00±0.05, P<0.05).(6) To analyze predictors of hospital stay and medical costs of AMI patients using multiple linear regression model. Age (β=0.553, P< 0.001), LDH (β=0.107, P< 0.001), ventricular arrhythmia (β=0.085, P< 0.001), serum glucose (β=0.21, P< 0.001), diuretics (β=0.068, P=0.004) and revascularization (β=0.061, P=0.004) were predictors of hospital stay in AMI. PCI (β=0.411, P< 0.001), K+(β=0.285, P< 0.001), revascularization (β=0.149, P<0.001), multivessel pathogenic changes (β=0.186, P< 0.001), ventricular arrhythmia (β=0.046, P=0.018) and urine protein (β=0.039, P=0.044) were predictors of total medical costs. PCI (β=0.417, P<0.001), revascularization (β=0.21, P<0.001) and multivessel pathogenic changes (P=0.208, P=0.005) were predictors of medical treatment costs. Age (β=0.551, P<0.001), LDH (P=0.143, P< 0.001), diuretics (β=0.092, P=0.001), ventricular arrhythmia (β=0.086, P=0.001), serum glucose (β=0.278, P<0.001), revascularization (β=0.11, P<0.001), heart rate (β=0.081, P=0.001), urine protein (β=0.086, P=0.001), and HDL (β=-0.197, P=0.038) were predictors of medication costs.(7) To analyze independent predictors of cardiovascular events of AMI patients in hospital using logistic regression model. Multivessel pathogenic changes (OR=3.288,95%CI [1.117-9.683], P=0.031) and LDH (OR=1.002,95%CI [1.000-1.003], P=0.009) were independent risk factors of acute heart failure. PCI (OR=0.113,95%CI [0.032-0.392], P=0.001) and aspirin (OR=0.012,95% CI [0.002-0.098], P<0.001) were independent predictors of reduced acute heart failure. Age (OR=1.088,95% CI [1.034-1.145], P=0.001), serum glucose (OR=1.177,95% CI [1.011-1.371], P=0.036) and urine protein (OR=7.267,95% CI [1.961-26.931], P=0.003) were independent risk factors of atrial arrhythmia. Aspirin (OR<0.001,95% CI [0.000-0.002], P<0.001) was independent predictor of reduced atrial arrhythmia. Heart rate (OR=1.054,95% CI [1.026-1.083], P <0.001) and urine protein (OR=15.921,95% CI [4.511-56.187], P<0.001) were independent risk factors of ventricular arrhythmia. SBP at admission (OR=0.978,95% CI [0.961-0.996],P=0.018) and aspirin (OR=0.011,95% CI [0.001-0.164], P=0.001) were independent predictors of reduced ventricular arrhythmia. Aspirin (OR=0.002, 95% CI [0.000-0.017], P<0.001) was independent predictor of reduced death. Age (OR=0.943,95% CI [0.913-0.973], P< 0.001), heart rate (OR=0.951,95% CI [0.929-0.974],P<0.001), LDH (OR=0.999,95% CI [0.998-1.000],P=0.034) and urine protein (OR=0.164,95% CI [0.048-0.564],P=0.004) were independent predictors of reduced event-free survival. SBP at admission (OR=1.020,95% CI [1.003-1.038], P=0.023) and aspirin (OR=2415.963,95% CI [76.511-76288.489], P<0.001) were independent protective predictors of event-free survival.(8) Impact of age on cardiovascular events and medical costs of AMI patients in hospital. Variance analysis showed that age rather than metabolic syndrome had significant impact on hospital stays and costs. And there was no age-MS interaction in the models (P>0.05). Older AMI patients had longer hospital stay, more chemical examination costs and medication costs, but less total medical costs, daily costs and medical treatment costs. Increased age was significantly associated with a higher rate of acute heart failure, atrial and ventricular arrhythmia, and a low rate of cardiac event-free survival (P<0.05).(9) To analyze predictors of medical costs of older AMI patients using multiple linear regression model. BMI (β=0.526, P< 0.001), PCI (β=0.315, P< 0.001), revascularization (β=0.104, P=0.001), ventricular arrhythmia (β=0.012, P=0.012) and urine protein (β=0.130, P<0.001) were predictors of total medical costs of older AMI patients. BMI (β=0.469, P<0.001) and PCI (β=0.351, P<0.001) were predictors of daily medical costs of older AMI patients.(10)To analyze independent predictors of cardiovascular events of older AMI patients in hospital using logistic regression model. NEFA (OR=1.012,95%CI [1.000-1.023], P=0.041) was independent risk factor of acute heart failure. PCI (OR=0.280,95%CI [0.100-0.785], P=0.016) and Hb (OR=0.979,95%CI [0.972-0.987], P<0.001) were independent predictors of reduced acute heart failure. Urine protein (OR=5.106,95% CI [1.865-13.980], P=0.002) was independent risk factor of atrial arrhythmia. PLIP (OR=0.380,95%CI [0.311-0.465], P<0.001) was independent predictor of reduced atrial arrhythmia. Serum glucose (OR=1.206,95%CI [1.060-1.371], P=0.004) and urine protein (OR=4.796,95%CI [1.542-14.920], P=0.007) were independent risk factors of ventricular arrhythmia. HDL (OR=0.148,95%CI [0.059-0.374], P<0.001) and statin (OR=0.160,95%CI [0.058-0.441], P<0.001) were independent predictors of reduced ventricular arrhythmia. Diabetes (OR=2.947,95%CI [1.605-225.992], P=0.020) was independent risk factor of death. Hb (OR=0.985,95%CI [0.972-0.999], P=0.034), betablocker (OR=0.021,95%CI [0.001-0.325], P=0.006), ARB (OR=0.053, 95%CI [0.003-0.953], P=0.046) and aspirin (OR=0.050,95%CI [0.003-0.800], P=0.034) were independent predictors of reduced death.(11) Cost-effective analysis. PCI was a high cost-effective therapy to AMI patients. MS and aging reduced the cost-effectiveness.Conclusions1. MS is associated with decreased event-free survival and increased daily medial costs of AMI patients in hospital, risk of which is similar with 1-2 MS components.2. High FBG, hypertension and HDL is associated with increased cardiovascular event of AMI patients in hospital and high BMI and high FBG is associated with higher medical costs.3. Older AMI patients have more cardiovascular events, longer hospital stay and higher medical costs.4. PCI is independent predictor of reduced acute heart failure in AMI at hospital. Urine protein is independent risk factor of both atrial and ventricular arrhythmia. Aspirin is a strong protective factor, which notably reduces worse cardiovascular events.5. PCI, twice revascularization and multivessel pathological changes are main predictors of medical costs of AMI patient. BMI and PCI are main predictors of older AMI patients.6. PCI is a higher cost-effective therapy to AMI patients. MS and aging reduces the cost-effectiveness of PCI. |
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