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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 10  |  Issue : 2  |  Page : 23-32

Clinical characteristics, management, and 1-year outcomes of patients with acute coronary syndrome admitted to a tertiary health-care center of Kerala: A prospective study


1 Department of Cardiology, Government Medical College, Kozhikode, India
2 Professor of Social and Preventive Medicine, Government Medical College Kozhikode, Kerala, India

Date of Web Publication14-Feb-2022

Correspondence Address:
Dr. Suneesh Kalliath
Department of Cardiology, Government Medical College, Kozhikode 673008, Kerala.
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/khj.khj_7_21

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  Abstract 

Background: There are limited data on the late outcome of the acute coronary syndrome (ACS) in India. We prospectively investigated the clinical characteristics, management, and 1-year outcomes of patients with ACS admitted to a tertiary care center of South India. Materials and Methods: In this prospective observational study, we enrolled 3149 adults hospitalized with a diagnosis of ACS between December 1, 2014 and March 31, 2017 at Government Medical College Kozhikode, Kerala. Patients were followed up at 30 days, 6 months, and 1 year. Primary outcome was all-cause mortality at 365 days. Secondary outcomes were 30-day mortality, sudden cardiac death (SCD), and major adverse cardiac events (MACEs) at 1 year after discharge. Results: A total of 3149 patients with ACS were admitted during the study period (48% with ST-elevation myocardial infarction [STEMI], 37% with non-ST-elevation MI [NSTEMI], and 15% unstable angina [UA]). The patients were of ages 58 ± 11.9 years. During hospitalization, the majority of the patients received guideline recommended drugs and percutaneous coronary intervention (PCI) was performed in 28%. Reperfusion therapy was performed in 88% of patients with STEMI (53% thrombolytic therapy and 45% including primary and rescue PCI). At 1 year, all-cause mortality and composite MACE after discharge were 14.4% and 17.6%, respectively. MACE included cardiovascular death (5.4%), re-infarction (15.7%), and non-fatal stroke (0.6%) after discharge. SCD at 1 year was 1.8%. The main factors associated with 1-year all-cause mortality and MACE were older age, prior history of ACS, ventricular tachycardia or ventricular fibrillation, right bundle branch block with Q wave, and left ventricular systolic dysfunction. Conclusion: One-year all-cause mortality after the admission of ACS was high, but post-discharge cardiovascular mortality was comparable to other developed countries. This highlights a better secondary prevention practices and risk stratification in our population.

Keywords: ACS in India, acute coronary syndrome mortality, delayed outcome of ACS in India, MACE after ACS, 1-year mortality of ACS, RDW in ACS, SCD after ACS in India


How to cite this article:
Kalliath S, Nair RG, Vellani H, Chakanalil SG, Muneer K, Deshabandu V, Mathew D, George B. Clinical characteristics, management, and 1-year outcomes of patients with acute coronary syndrome admitted to a tertiary health-care center of Kerala: A prospective study. KERALA HEART J 2021;10:23-32

How to cite this URL:
Kalliath S, Nair RG, Vellani H, Chakanalil SG, Muneer K, Deshabandu V, Mathew D, George B. Clinical characteristics, management, and 1-year outcomes of patients with acute coronary syndrome admitted to a tertiary health-care center of Kerala: A prospective study. KERALA HEART J [serial online] 2021 [cited 2022 Sep 25];10:23-32. Available from: http://www.csikhj.com/text.asp?2021/10/2/23/337624




  Introduction Top


Almost half of the disease burden in low- and-middle-income countries is now from noncommunicable diseases.[1] Coronary artery disease (CAD) contributes a major share in this. Acute coronary syndrome (ACS) is the most common cause of mortality in patients with CAD. There are limited data on the late outcome of ACS in India and other South Asian countries. Most of the real-world evidence about patients and late outcome of ACS are from multinational registries, which are based on the data from developed countries.[2],[3],[4] Little is known about patients with ACS in South Asian countries.[5] Multinational registries often represent statistical averages for the participating centers rather than representing a real, existing geographical population, and often data are hampered by significant selection and information bias.[2],[3],[4],[6],[7] Hence, more representative single-center studies are needed to increase awareness of cardiovascular disease burden, its management, and outcomes in south Asia. This is important to establish appropriate preventive and management strategies. Single-center prospective studies on the long-term outcome of ACS are deficient from South Asian countries. The existing studies which assessed late outcomes are either registry-based multicenter studies or retrospective analysis of hospital-based data.[5],[8],[9] We did an effort to prospectively investigate the clinical characteristics, management, and 1-year outcomes of patients with ACS admitted to a tertiary care center of South India.


  Materials and methods Top


This study was conducted in Government Medical College Kozhikode, Kerala, a tertiary care teaching hospital in South India, serving a population of approximately 10 million (Referral center for seven districts of North Kerala: Kasaragode, Kannur, Kozhikode, Wayanadu, Malappuram, Palakkad, and Trissur).

The study period was from December 1, 2014 and March 31, 2017. In this prospective observational study, we enrolled all adults hospitalized with a diagnosis of ACS between December 1, 2014 and March 31, 2016. Patients with age less than 18 years, life expectancy less than 6 months due to obvious noncardiac condition, and patients who have refused consent to participate in the study were excluded. Patients were recruited consecutively to avoid selection bias. Data were recorded prospectively at admission, during hospital stay, at 30 days, 6 months, and 1 year. All documented findings were predefined. Standard structured questionnaire was used to collect data at admission, during the hospital stay, and at 1 year. Baseline parameters were collected from all recruited patients, in a predesigned proforma, at the time of admission or during the hospital stay which included demographic parameters, type of ACS, pulse rate, systolic blood pressure (SBP), heart failure or not, cardiogenic shock or not, cardiac arrest or not, Killip class for STEMI, TIMI grade for NSTEACS, and mechanical complications. History and risk factors were recorded such as hypertension and diabetes mellitus status, known dyslipidemia or not, smoking status (nonsmoker, current smoker, or ex-smoker), chewing tobacco or not, known cerebrovascular disease or not, known family history of CAD, previous documented ACS, previous documented coronary angiogram and findings, and previously documented revascularization (PCI or CABG). Key investigations at the time of admission such as hemoglobin (Hb), total leukocyte count (TLC), platelet count (PLT), red cell distribution width (RDW), platelet distribution width (PDW), mean platelet volume (MPV), creatinine (Cr), random blood sugar (RBS), and troponin-I quantitative (In NSTEACS patients only) were documented. 12-lead ECG for arrhythmias and heart block for indicated patients and 2D-echocardiography for ejection fraction (EF) were performed. In-hospital clinical events such as bleeding during hospital stay (major or minor bleeding), mechanical complications during hospital stay (Ventricular septal rupture, acute mitral regurgitation, free-wall rupture), and death were documented.

All patients, who were discharged alive, were followed up at 30 days, 6 ± 1, and 12 ± 1 months. Follow-up was either by direct follow-up visit or by telephonic interview to the patient or a third party (e.g., relative/friend and family physician). Follow-up data included clinical outcomes after discharge. Lost to follow-up was defined as failed to contact after five attempts of phone calls. A window of 30 days was allowed for the 6-month and 12-month follow-up. The primary outcome was all-cause mortality at 365 days. Secondary outcomes were 30-day mortality, sudden cardiac death (SCD), and MACE at 1 year after discharge.

Late Consequences of Acute Coronary Syndromes (GRACE) Follow-Up data of 70,395 patients from 14 different countries was published recently (2014).[7] Mortality between 6 months and 2 years was 5.7%. Sample size calculation of our study was based on an expected event rate of 5.7% at 1 year. On the basis of the above assumptions sample size was calculated as 2129 (accuracy 1%). Considering an expected loss to follow-up of maximum 10%, the sample size (n) required was 2366.

Continuous variables were presented as mean ± standard deviation (SD) and compared with Student’s t test or Mann–Whitney U test. Discrete variables were presented as frequencies or percentages and were compared with chi-square or Fisher exact tests, as appropriate. Univariate analysis followed by multivariate analysis was done for determining independent predictor of mortality. Multivariate analysis was done by the logistic regression method. Data were analyzed by using the Statistical Package for Social Sciences (SPSS) software program, version 18.0 for Windows (SPSS, Chicago, Illinois). All P-values were two-tailed with a significance defined as P ≤ 0.05.


  Results Top


Study population

A total of 3171 patients with the suspected ACS were enrolled during the 2-year study period (December 2014–March 2016) [Figure 1]. Sixteen patients were excluded because of noncardiac diagnosis. Six patients had expected life expectancy of less than 6 months and were excluded from the study. So total patients with ACS recruited in this study were 3149. A total of 223 (7%) patients were lost to follow-up at 1 year and excluded from the analysis of primary outcome. So a total of 2926 patients were eligible for analysis of primary outcome with a follow-up rate of 93%. Loss to follow-up was 1% at 30 days and 1.4% at 6 months. But this figure rose to a total of 7% at 12 months. In-hospital mortality was 8%. The remaining 2674 patients were discharged alive and were eligible for analysis of secondary outcome. [Table 1] shows the baseline demographic and clinical characteristics of the study population. For the entire patient group, the mean age was 58 ± 11.9 years (range: 26–98 years). They were mostly in the 41–65 years age group (64%) and men were 75%. A total of 298 patients (10.2%) were labeled as young ACS (age less than 41 years). 77% of patients were from the rural area and approximately 50% of patients were from Kozhikode district. The mean duration of hospitalization was 5.27 ± 2.5 days (range 1–17 days). STEMI was 48%, NSTEMI was 37%, and UA was 15% of patients. Dyslipidemia (87.7%), hypertension (55.2%), and diabetes (46.2%) were the leading risk factors for CAD. Other risk factors included cigarette smoking (45.6%) and family history of CAD (8.5%). Current smokers were 17.2% and ex-smokers were 28.4%. Previous history of stroke or transient ischemic attack was present for 135 patients (4.6%). Patients with NSTE-ACS generally had worse medical history and more risk factors compared with patients with STEMI, but current smokers were more in STEMI group (22% vs. 13% with P = 0.001). Prior history of myocardial infarction was significantly more in NSTEACS group than in STEMI group. Also typical history of effort related angina was more in the NSTEACS group. In total, 682 patients (23.3%) had a prior documented history of ACS and 412 patients (14.1%) had undergone coronary angiogram (CAG) in the past. Of these patients who underwent CAG previously, 6.3% were diagnosed as normal coronaries, 22.1% were single-vessel disease, 29.6 were double-vessel disease, 35.4% were triple-vessel disease, and 6.6% had LMCA disease. A total of 171 patients (5.8%) and 37 patients (1.3%) had undergone PCI and CABG, respectively, in the past. Laboratory parameters were comparable between two groups of ACS [Table 2].
Figure 1: Study flowchart

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Table 1: Baseline demographic and clinical characteristics of the study population

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Table 2: Comparison of laboratory parameters of patients

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In the STEMI group, 120 (75.6%) patients presented in Killip Class I. The anatomical sites of infarction were mainly the inferior (53%) and anterior (43%) walls. Men were more likely to have STEMI (78.1 vs. 71.2%, P < 0.001), whereas women were more likely to have NSTEMI/UA (28.8 vs. 21.9%, P < 0.001). Resuscitated cardiac arrest (3.1%), cardiogenic shock (6.8%), re-infarction (2.3%), major bleed (0.5%), and stroke (0.3%) were the major complications during the index hospitalization. Overall 4.5% of patients had complete heart block (CHB), 4% had AF, and 4% had either ventricular tachycardia (VT) or ventricular fibrillation (VF) during the admission or initial hospital stay. The rate of ventricular septal rupture, acute MR, and free wall were 1%, 0.2%, and 0.09%, respectively.

In-hospital management and medications at discharge

The most commonly used medications were dual antiplatelets (DAPTs) (99%), statins (99%), β-blockers (76%), and ACE-I/ARB (83%) with little difference between patients with NSTE-ACS or STEMI. Among the anti-thrombin medications, unfractioned heparin (UFH) was given for 58%, low-molecular-weight heparin (LMWH) for 13% and bivalirudin for 0.1% of patients. Fifty-four percent of patients with STEMI received fibrinolytic therapy (mainly with streptokinase). During the index hospitalization, a percutaneous coronary intervention (PCI) was performed in 28% of patients; nearly all of these patients received a stent. Among the patients who underwent PCI, 94.3% received drug-eluting stents (DES) and 4.7% received baremetal stents (BMS). During the hospital stay, 0.9% of the patients underwent CABG surgery. Among patients with STEMI, 45% underwent PCI during index hospitalization and 11% did not receive any form of acute reperfusion therapy (PCI or fibrinolytic therapy) within 24 h of admission. The mean door-to-balloon and door-to-needle times were 69.73 ± 32 and 21.87 ± 10.6 min, respectively. At discharge, medication use included aspirin (99%), ADP inhibitors (99%), statins (99%), β-blockers (84%), ACE-I or ARB (91%), aldosterone inhibitors (23%), and nitrates (61%).

Primary and secondary outcomes

Overall in-hospital mortality was 8.6%; for STEMI it was 11% and for NSTEMI it was 6.3%. The rate of all-cause death at 30 days was 10%. This figure rose to 12.4% by 6 months and 14.4% by 12 months and was significantly higher in patients with STEMI compared with those with NSTEMI and UA. A similar trend was seen for cardiovascular death at 1 year after index hospitalization.

During the 12-month follow-up, 1-year total post-discharge mortality was 6.3% and death due to noncardiovascular cause was 0.9%. Overall cardiovascular death at 1 year after index hospitalization was 5.4%. The rate of SCD at 12 months was 1.8% (n = 49). Nonfatal stroke at 12 months occurred in 0.6% (n = 17) of patients.

Of the entire patient group, 421 patients (15.7%) experienced at least one episode of recurrent ACS after hospital discharge, during 1-year follow-up. Patients with STEMI were found to have higher rates of ACS during the 12 months after discharge; 15.7% (n = 421) had recurrent ACS. The combined endpoint (cardiovascular death, nonfatal stroke, or recurrent ACS) or major adverse cardiovascular events (MACEs) at 1 year was 17.7% and was higher among STEMI (19.4%) than NSTEACS (16.2%).

Predictors of 1-year outcome

[Table 3] shows the result of univariate analysis showing predictors of 1-year all-cause mortality at 1 year after admission. Female sex, patients from urban area, STEMI group compared to NSTEACS, diabetes, history of prior stroke or TIA, previous history of MI, age more than 60 years, heart rate less than 50 or more than 100/ min, cardiogenic shock, VT or VF during hospital stay, re-infarction during hospital stay, major or minor bleed during hospital stay, CHB, presence of right bundle branch block with Q wave (QRBB), lower Hb level, higher PLT, higher RDW, higher serum Cr, and lower EF were associated with increased 1-year mortality after admission. On multivariate analysis by logistic regression methods, the factors independently associated with increased risk of all-cause mortality at 1 year were age more than 60 years, STEMI compared to NSTEACS, history of prior MI, re-infarction during hospital stay, EF less than 40%, QRBB, elevated Cr, and elevated RDW. β-Blocker administration during hospital stay was found to be protective [Figure 2]A.
Table 3: Result of univariate analysis for predictors of 1-year all-cause mortality

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Figure 2: Result of multivariate analysis for predictors of all-cause mortality (A) and MACE (B) at 1 year

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[Table 4] shows the result of univariate analysis showing predictors of MACE at 1-year after discharge. Age more than 60 years, prior history of MI, EF less than 40%, VT or VF, CHB, and QRBB were independently associated with increased risk of post-discharge MACE at 1 year. Revascularization after discharge (PCI or CABG) was found to be protective for MACE [Figure 2B].
Table 4: Result of univariate analysis for predictors of MACE at 1 year

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  Discussion Top


This study was a prospective analysis of 2926 patients with definite ACS in a tertiary health-care center of South India. It was one of the largest prospective studies in India looking into information on descriptive epidemiology, practice patterns, and delayed outcomes of complete spectrum of patients with ACS. It was the largest single center study in Asia looking into 1-year mortality and MACE after discharge of patients admitted with ACS.

The mean age was comparable to CREATE Indian registry and ACCESS registry data, but less than patients of Kerala ACS registry and studies from developed countries.[2],[3],[4],[10],[11],[12] In terms of ACS types, patients in our study were broadly similar to those in observational studies conducted in Western populations.[6],[7],[13] Just over half (48%) of the confirmed patients with ACS had STEMI. In the second Euro Heart Survey (EHS-ACS-II), the ACS population comprised almost equal proportions with NSTE-ACS and STEMI (48% and 47%, respectively).[14] Also the proportion of STEMI was comparable to studies of developed countries (NRMI 47%, Portuguese registry of ACS 45%), Gulf registry data (GULF RACE 2 45%), and some developing countries (ACCESS Registry 46%).[9],[10],[12],[15],[16] But the ratio of STEMI (48%) was lower compared to previous Indian registry data and higher than Kerala ACS registry data.[10],[17] In the multinational GRACE registry, 30%–40% had STEMI, whereas 60%–70% had NSTE-ACS.[2],[3],[4],[6],[7] This study showed a higher prevalence of diabetes and hypertension compared recent Indian studies.[10],[18] A community-based study in Kerala showed that the prevalence of CAD risk factors is high compared to the United States.[19] Serial epidemiological studies in India showed a rising trend of prevalence of CAD risk factors.

Approximately 88.1% of patients with STEMI were either fibrinolyzed or reperfused by primary PCI and only 11.9% were solely managed medically. But the rate of primary PCI was only 35% and which is far low compared to any Western data.[2],[3],[4],[6],[11] Approximately 35% of total patients with STEMI reaching to our ED were either from low socioeconomic background or without private or government insurance benefits and have to pay the cost out of pocket. So they prefer fibrinolysis. The most commonly used fibrinolytic agent was streptokinase, again possibly reflecting its lower cost relative to newer fibrinolytic agents.[9],[20],[21],[22],[23] Being a referral center of large area of Northern Kerala and serving a population of approximately 10 million, approximately 13% of our patients with STEMI were referred to our center only after fibrinolyzed from the peripheral hospitals. Although PCI and CABG were performed relatively infrequently, inappropriate thrombolysis for NSTEACS was relatively low (1.3% thrombolysis in patients with NSTEMI) compared to CREATE (3.5% thrombolysis in patients with NSTEMI), GRACE (5.0% in patients with NSTEMI), and Kerala ACS registry (19% thrombolysis in patients with NSTEMI).[3],[4],[10],[17] Overall 28% of ACS and 45% of patients with STEMI underwent PCI at admission, considerably higher than CREATE and Kerala ACS registries, but relatively low rates of intervention compared with North American or European registries.[4],[9],[10],[11],[23] Even though the revascularization rate by primary angioplasty was only 35% in our study, which is low in the current era of advanced STEMI care, this figure is better compared to Gulf RACE 2 registry (7%), ACCESS registry (22%), SPACE registry of Saudi Arabia (17.5%), IPACE registry of Iran (17%), and Portuguese registry of ACS (19%).[9],[10],[12],[15],[16],[24] The rates of PCI in EHS-ACS-II and GRACE were 35% to 37% (NSTE-ACS) and 58% to 64% (STEMI).[6],[7],[14] Our patients with STEMI were reperfused within acceptable lengths of time. Approximately 83% of patients with STEMI underwent fibrinolysis within 30 min of arrival, but only 67.2% had door-to-needle time within 90 min for primary PCI.

Compared with the CREATE study, patients in our study were more likely to receive key evidence-based ACS medications and underwent coronary angiography (30% vs. 23% in CREATE) or PCI (28% vs. 7.5%) but a lower proportion of patients with ACS underwent CABG for revascularization during index hospitalization (1% vs. 2.9%).[10] The above figures are better than that of Kerala ACS registry (coronary angiography 20% and PCI 7.5%).[17] Similar to the results of other recent studies on ACS, ours also showed high compliance with guideline-directed medications during the index hospitalization in patients with ACS.[12],[15],[18] In-hospital mortality was 8% in the current study which is high in this current era of management. This is higher than in-hospital mortality reported in CREATE registry (5.6%) and Kerala ACS registry (4%).[10],[17] In-hospital mortality rates for STEMI in this study (10.6%) were higher than GRACE (7%), Euro Heart Survey ACS II (6%), and CREATE registry (8.6%).[3],[10],[14] The high mortality rate in this study may be due to more proportion of high-risk patients. Similarly, 30-day mortality was 10% and which is higher than CREATE registry (6.7%) and ACCESS registry (3.6%). Lower primary PCI rate for STEMI and delayed door-to-balloon time also contribute to high in-hospital and 30-day mortality.[23],[25] Despite high in-hospital mortality, 1-year post-discharge cardiovascular mortality (5.4%) is comparable to other Asian (Iran registry 5.7%, Gulf Race-2 12%) and International data (ACCESS registry 8.4%, EHS-2 7.4%).[9],[12],[15],[16] The 12-month all-cause mortality rate after admission was higher among patients with STEMI (17.5%) than NSTEMI (13.1%) and UA (7.6%) in our study. This contrasts with other studies showing a higher early mortality risk in STEMI and a higher late risk (0.5–10 years) in NSTE-ACS.[2],[3],[4],[8] The 12-month all-cause mortality in a German PCI registry was 14% for STEMI, 12% for NSTEMI, and 4.8% for UA.[26] One-year all-cause mortality of NSTEACS patients in a Korean nation-based study was 14%.[27] A recent study conducted in South India reported 1-year mortality of patients with ACS as 2.5%.[18] It is probable that the low mortality rate in that study may be because the study population belonged predominantly of low- or intermediate-risk group with generally low rates of severe complications and 80% were of urban population. Two-year all-cause mortality for NSTEMI was 15% in the multicenter OASIS study, in which 12 centers were from Indian subcontinent.[5]

Our data concur with other studies showing that older patients, those with adverse outcomes during hospitalization, poor left ventricular function are at higher risk for death in the ensuing months.[6],[11],[13] The most important risk factors for death were older age, cardiac arrest, re-infarction during hospital stay, previous ACS, QRBB, VT or VF, higher RDW, higher Cr, and EF less than 40%. Similar trends were seen for MACE also. β-Blocker administration during the hospital stay was found to be beneficial (OR 0.2 95% C.I 0.15–0.27). The beneficial role of β-blockers to reduce mortality has been reinforced, even with the small cohort of patients with ACS. Univariate analysis showed that the presence of diabetes mellitus was found to be a significant predictor for high 1-year all-cause mortality as observed by others.[28] But hypertension and history of smoking did not pose any higher risk for mortality at 1 year.

RDW has been reported to be a predictor of cardiac events in CAD. Bekler et al.[29] reported that high RDW level on admission was associated with increased long-term mortality in patients with NSTEACS. Weiss et al.[30] showed that inflammation may bring about changes in red blood cell maturation by disturbing the red cell membrane, thereby leading to increased RDW. Inflammation may have a key role in the underlying biological mechanism responsible for increased RDW levels. During the inflammatory process, cytokines might affect bone marrow function and erythrocyte maturation induced by erythropoietin, elevating RDW levels.[31],[32] This is the first Indian study, which showed a positive correlation between elevated RDW and increased mortality in patients with ACS.

Adjusted analysis of predictors of MACE at 1 year were age more than 60 years, previous ACS, either VT or VF during index hospitalization, CHB, QRBB, and EF less than 40%. Post-discharge revascularization (either PCI or CABG) was associated with lower MACE at 1 year. A high RDW level (>14) on admission is associated with increased long-term mortality ACS. Rising trend of prevalence of DM (46%) and HTN (55%) was noted in the study. Age more than 60, H/O prior ACS, QRBBB, VT or VF at admission, and EF less than 40% were associated with higher all-cause mortality and post-discharge MACE at 1 year.

The predictors of 1-year mortality and MACE at 1 year have implications for ACS quality improvement efforts and better risk stratification. High-risk patients at the time of admission and adverse cardiovascular event during the index hospitalization were the major predictors of mortality and MACE at 1 year. This highlights the importance of appropriate in-hospital management including facilities for early intervention for patients with STEMI and strict adherence to guideline-directed medical therapy both during the hospital period and at the time of discharge. In fact, appropriate evaluation and early risk stratification to streamline management may be one potential solution to reduce the adverse outcome in patients with ACS.

Strength and limitations of the study

The primary strengths of our data are the large sample size and coverage of complete spectrum of consecutive patients with ACS admitted to a high-volume tertiary care referral center of Kerala. It is one of the largest prospective studies in South Asia looking into information on descriptive epidemiology, practice patterns, and delayed outcomes of patients with ACS. Although the study included a large cohort of patients, it was not a population-based registry or multicenter study and selection bias could have occurred. There is an inherent selection bias because the study center was a referral center of seven major districts of north Kerala and majority of the patients might be high risk and hence the study populations may not be true representative of the state. So the study results cannot be fully projected to the nation as a whole.[25] Although we compared our data with other international ACS registries, caution has to be taken about making absolute inferences, mainly because of the patient age and timing differences between these studies and ours. Loss-to-follow-up rate at the end of 12 months was 7%. So 1-year outcome could be underestimated. Adherence to guideline-recommended medications is an important factor that affects delayed outcome in ACS. We could not assess the compliance to medications in our study population, which is a major limitation of this study. The patients at the highest risk, like those who died at ED or before reaching the hospital, were not included in our study and hence mortality rate could be underestimated.

In conclusion, 1-year all-cause mortality after the admission of patients with ACS is still high compared to previous studies from developed or developing countries. But overall post-discharge mortality is comparable to other developed countries, highlighting a better secondary prevention practice and risk stratification in our population. We found that our patients with ACS are treated with high levels of adherence to guideline-recommended in-hospital medications, but there was a substantially low rate of primary PCI for STEMI compared to developed countries. But the rate of PCI was far better compared to previous Indian or Kerala registry data.

What is already known is that there are multiple studies about early outcomes of ACS in south Asia. But studies that assessed late outcomes of a broad spectrum of patients with ACS are limited.

What this study adds is that the study assessed 1-year all-cause mortality and MACE of a large cohort of patients with ACS of South India. The study also assessed the prevalence of SCD of patients with ACS.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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