| Background:Approximately 6%-27%of patients hospitalized for acute myocardial infarction(AMI)worldwide were found to have no standard modifiable cardiovascular risk factors(SMuRF)at their first presentation.These patients were named SMuRF-less patients.Recently,some studies reported that SMuRF-less patients had unexpectedly higher crude in-hospital mortality compared with those with SMuRF.However,the results were conflicting after adjusting for patient characteristics and treatment.Further,how these differences in treatment and outcomes between both groups changed over time remains unclear.There is no nationally representative data to investigate the characteristics,treatment,outcome,and temporal trend of the SMuRF-less group among AMI patients in China.Objective:(1)To compare the differences in characteristics,quality of care,and inhospital outcomes between SMuRF-less and SMuRF patients,and to explore the accounting factors to explain these differences(if any).(2)To examine trends in these differences over time.Methods:The study used the data from the China Patient-centered Evaluative Assessment of Cardiac Events Retrospective Study of Acute Myocardial Infarction(China PEACERetro AMI study),which offers a nationally representative sample of patients hospitalized for AMI by using a two-stage random sampling procedure in 2001,2006,2011,and 2015.SMuRF was defined as having at least one of the following risk factors:hypertension,diabetes,smoking,and hypercholesterolemia.Multivariable logistic regression with generalized estimating equations was used to compare the characteristics,treatment,and mortality during hospitalization between both groups.To compare treatment and mortality between SMuRF and SMuRF-less,multivariate generalized logistic regression models were used.To explore whether these differences varied over time,an interaction term between SMuRF status and study year was added to the aforementioned regression models.Results:Totally,16,541 patients with ST-segment elevation myocardial infarction(30.0%women;mean[Standard Deviation]age,65[13]years)were included,and 19.9%were SMuRF-less.4,141 patients with non-ST-segment elevation myocardial infarction were included,with a mean age of 68±12 years,41.1%were female,and 14.7%were SMuRFless ones.The proportion of the SMuRF-less group decreased between 2001 and 2015.These patients were older and presented with more severe clinical conditions including a higher proportion of cardiogenic shock at admission and a higher mini-Global Registry of Acute Coronary Events risk score.SMuRF-less patients were less likely to have chest discomfort and be admitted to the cardiac ward.Among patients with ST-segment elevation myocardial infarction,(1)SMuRF-less patients were less likely to receive treatment compared with SMuRF patients,including reperfusion therapies(51.6%versus 60.9%),primary percutaneous coronary intervention(17.3%versus 28.8%),aspirin(89.0%versus 94.7%),β-blockers(78.3%versus 85.7%),angiotensin-converting enzyme inhibitors/angiotensin receptor blockers(49.9%versus 68.1%),and statins(69.9%versus 85.1%)(P<0.001 for all).After adjusting for age,sex,medical histories,and clinical presentation at admission,these differences persisted.(2)Over time,utilization of reperfusion,primary percutaneous coronary intervention,aspirin,and statins increased substantially in both groups(P trend<0.05),but these treatments remained lower in the SMuRF-less group than that in the SMuRF group.The difference in aspirin increased significantly during the past 15 years(P for the interaction between SMuRF status and study year=0.018).And the differences in other treatments between both groups did not improve significantly.(3)SMuRF-less patients had higher in-hospital mortality(18.5%versus 10.5%,P<0.001).In both groups,the highest hazard function for death was in the first 24 hours.After adjusting for age,sex,medical histories,and clinical presentation,the difference remained significant(Odds ratio[OR]1.42;95%Confidence interval[CI]1.25-1.60).However,after further adjustment for in-hospital treatment,the difference was no longer significant(OR 1.06;95%CI 0.93-1.21).However,the differences in patient characteristics and treatment between both groups could not account for the excess mortality within the first 24 hours.(4)Between 2001 and 2015,the inhospital mortality did not decrease significantly in SMuRF-less patients(P trend=0.115),and the difference in mortality did not narrow.In patients with non-ST-segment elevation myocardial infarction,(1)SMuRF-less patients were less likely to receive medications,even after adjusting for age,sex,and other characteristics.However,the difference in invasive strategy was no longer significant after adjusting for age.(2)The utilization of dual antiplatelet therapy,anticoagulants,statin,and invasive strategy has improved for both groups(P trend<0.05).Notably,the differences in the use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and invasive strategy tended to increase but did not reach statistical significance(P interaction>0.05).(3)Regarding in-hospital outcomes,the in-hospital mortality in SMuRF-less patients was nearly twice as much as in SMuRF patients(17.1%versus 9.3%,P<0.001).But such difference disappeared after adjustment for clinical characteristics(OR 1.20;95%CI 0.90-1.61).(4)During the study period,no declines in mortality of SMuRFless and SMuRF groups were observed(P trend>0.05),and such differences did not narrow.In 2015,the mortality in SMuRF-less patients remained higher than in SMuRF patients(age-and sex-adjusted OR 1.86;95%CI 1.33-2.60).Conclusions:In China,nearly one in five patients with acute myocardial infarction had no SMuRF.Compared with SMuRF patients,SMuRF-less patients had worse patient profiles and poorer treatments,and higher mortality.These differences in treatment and in-hospital mortality between both groups did not improve over time. |
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