Journal of the Indian Academy of Geriatrics

: 2023  |  Volume : 19  |  Issue : 1  |  Page : 29--35

Cognitive decline among older adults who developed acute coronary syndrome during hospitalization for non-cardiac illness

Priya Vijayakumar1, Arun David1, M Vijayakumar2,  
1 Department of Geriatrics, AIMS, Kochi, Kerala, India
2 Department of Cardiology, AIMS, Kochi, Kerala, India

Correspondence Address:
Priya Vijayakumar
Department of Geriatrics, AIMS, Kochi, Kerala


Background: Atypical presentations of acute coronary syndrome (ACS) delay its recognition and treatment in the elderly patients. Functional decline and delirium which are common to the elderly during hospitalization, leads to cognitive impairment and poor health outcomes. Steps taken for its prevention is usually not considered the top priority by the cardiologist. The present study was conducted to identify cognitive decline among elderly patients who developed ACS during hospitalization for noncardiac illness and their outcome. Materials and Methods: Three hundred and ten elderly patients above 60 years of age with ACS were included from June 26, 2020 to October 13, 2020. Subjects were divided into those admitted primarily due to an ACS (Group I, n = 94) and those developing ACS following admission for noncardiac illness (Group II, n = 216). Co-morbidities, medications, investigations, management, clinical outcome, and Montreal Cognitive Assessment scale were compared between the two groups at the time of admission, after 30 days and after 6 months. Results: Majority of the subjects were admitted due to acute kidney injury (27.1%) in Group II and had a non-ST elevation ACS (90.2%). Optimum management was given to a lesser extent due to the clinical condition of these patients. Poor clinical outcome, cognitive impairment during hospitalization and cognitive decline during follow-up was more in Group II. Conclusion: Clinicians must be vigilant for the development of cognitive impairment and cognitive decline when an elderly patient is admitted to the hospital, as early detection and optimum management provides better clinical and cognitive outcome.

How to cite this article:
Vijayakumar P, David A, Vijayakumar M. Cognitive decline among older adults who developed acute coronary syndrome during hospitalization for non-cardiac illness.J Indian Acad Geriatr 2023;19:29-35

How to cite this URL:
Vijayakumar P, David A, Vijayakumar M. Cognitive decline among older adults who developed acute coronary syndrome during hospitalization for non-cardiac illness. J Indian Acad Geriatr [serial online] 2023 [cited 2023 Jun 3 ];19:29-35
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Full Text


Acute coronary syndrome (ACS) is termed when a myocardial infarction is suspected or confirmed in a patient. It is diagnosed with an increase or a decrease in the cardiac troponin level after a steep rise in cardiac troponin value, with at least one value of more than 99th percent of upper reference limit of normal.[1] This should be along with supportive evidence of either the typical symptoms, changes in the electrocardiograph (ECG), newly detected regional wall motion abnormality in the echocardiography or when there is a new loss of viable myocardium detected through imaging.[2] Literature shows that 9%–14% of NSTEMI patients had normal coronary vessels or no coronary vessel with more than 50%–60% stenosis on coronary angiography. These patients come under the type 2 ACS according to the Joint Task Force definition of ACS,[3] and they had a better clinical outcome compared to those with a coronary lesion.[4]

Around 60% of the total ACS occurs in the elderly patients. The ACS-related death is also higher among them (80%). Even though elderly patients are not included in many of the clinical trials of ACS, literature shows that they more commonly had atypical presentations, non-ST elevation ACS, higher in-hospital mortality, and recurrent ACS.[5] During a hospital admission for noncardiac illness, the elevation of troponin is due to myocardial injury which occurs mainly due to demand–supply mismatch. Such an increase in blood concentrations of cardiac troponin is seen with sepsis, focal infections, renal failure, anemia, seizure, malignancy, exacerbations of bronchial asthma or chronic obstructive pulmonary disease, stroke, electrolyte imbalance, peripheral vascular disease, and postsurgery. The elderly patients have worse outcomes after an ACS due to their co-morbidities and a reduced likelihood of receiving adequate management because of concerns about drug toxicity. Optimum management is often used to a lesser extent in the elderly patients due to their clinical condition. The stress caused by noncardiac illnesses on the cardiovascular system like tachycardia, hypotension, abstinence from regular medication such as aspirin, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blocker (ARB), and associated conditions such as anemia, renal dysfunction, and electrolyte imbalance contribute to the development of ACS.

Literature has shown that elderly patients who received recommended treatment after an ACS had lower rates of mortality in the hospital than those who did not.[4] The side effects of medication can be overcome by adjusting the dose of medication according to age, gender, renal function, and volume of distribution.[6] During hospital admission, a risk of functional decline and delirium should be considered among the elderly patients. Many a time, guideline-based optimal therapy was not given in this group due to the fear of complications and hence the outcome was also poor. There is a paucity of data in this domain, and hence in this context, this study was conducted to assess the risk factors, level of guideline-based treatment, cognition impairment, and cognitive decline among elderly patients hospitalized primarily for ACS and who developed an ACS posthospitalization for a noncardiac illness.

 Materials and Methods

Selection and description of participants

A prospective observational study was conducted in a Tertiary Care Centre in Kochi from June 26, 2020 to October 13, 2020. As there were no previous studies taking into account all the noncardiac illnesses leading to an ACS, a pilot study was conducted. Based on the pilot study results of the prevalence of ACS following admission for the noncardiac illnesses in the elderly patients (76%), conducted in 100 samples and with 20% relative precision and 95% confidence, the minimum sample size came to 310 samples.

Inclusion and exclusion criteria

Elderly patients more than 60 years of age who were admitted to the hospital with either a primary ACS or those who developed ACS following admission for a noncardiac illness were included in the study. Subjects who were lesser than 60 years of age, who were not admitted due to an ACS nor developed an ACS following admission for a noncardiac illness and those who were not willing to participate in the study were excluded from the study.

Technical information

The study was initiated after obtaining clearance from the ethics committee of the institute. After screening for inclusion, patient consent was obtained for participating in the study. Patient details including socio-demographic data, past medical history, medications on admission, and the reason for current admission were obtained. After the admission, details about ECG changes during ACS, cardiac troponin levels, changes in the echocardiogram were noted. The study group was divided into two based on the time of development of ACS, at initial presentation or after admission for a noncardiac illness. The management given to the subjects of the two groups was noted in detail. The clinical outcome of the patient in the hospital was noted, including total number of days admitted. Montreal cognitive assessment tool was used for the assessment of cognition during hospitalization, after 1 month and after 6 months.


Statistical analysis was performed using IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. Categorical variables were expressed using frequency and percentage. Chi-square with continuity correction was used to test the statistical significance of the association of all variables between groups. A P < 0.05 was considered to be statistically significant.


Baseline characteristics

During June 26, 2020–October 13, 2020, a total of 12,262 subjects were admitted to the hospital [Figure 1]. Out of this 4329 (35.3%) were elderly patients of >60 years of age. The total number of subjects who were admitted with or developed an ACS after admission were 310 (7.16%). The data of 310 elderly patients were included in the study after screening according to the inclusion criteria. Of these, 94 (30.3%) subjects were admitted primarily with ACS, and they were taken as controls (GROUP-I). The rest of 216 subjects (69.6%) were admitted for other illnesses, following which they developed ACS during the illness (GROUP-II). In Group II, the reason for the current admission to the hospital is shown in [Table 1]. Majority of the subjects were admitted due to acute kidney injury (n = 84, 27.1%) following which they developed an ACS in hospital. The second most common cause was Sepsis, which was seen in 51 subjects (16.5%). The rest of the causes are shown in [Table 1].{Figure 1}{Table 1}

Comparison between the groups

The major observations seen in the two groups are shown in [Table 2]. The mean age was similar between the groups, with subjects admitted to the hospital for noncardiac illness being older (72.65 vs. 71.03 years). The mean number of days hospitalized was also almost similar with an increase among the subjects admitted for noncardiac illness (10.34 vs. 9.6 days). Male subjects were more in both the groups. Female subjects were more in the group admitted with noncardiac illness (n = 58, 26.9% vs. n = 24, 25.5%).{Table 2}

In the past medical history, systemic hypertension (n = 158, 73.1% vs. n = 65, 69.1%), coronary artery disease (n = 100, 46.3% vs. n = 41, 43.6%), dyslipidemia (n = 79, 36.6% vs. n = 27, 28.7%), cerebrovascular accident (n = 27, 12.5% vs. n = 8, 8.5%), and history of Coronary artery bypass graft (n = 24, 11.1% vs. n = 9, 9.6%) were seen more among the subjects admitted with noncardiac illness who later developed an ACS. The use of antiplatelets (n = 131, 60.6% vs. n = 52, 55.3%), Beta-blockers (n = 107, 49.5% vs. n = 45, 47.9%), and ACE inhibitors (n = 6, 2.8% vs. n = 2, 2.1%) on admission was more among the subjects who were admitted to the hospital due to noncardiac illnesses. Initial cardiac troponin elevation was seen more among the subjects admitted with ACS (n = 91, 96.8% vs. n = 200, 92.6%), but the subsequent values were elevated more among the subjects in the Group II. There was a higher percentage of non-ST elevation ACS among the subjects who were admitted to the hospital due to non-cardiac illnesses (n = 195, 90.3% vs. n = 75, 75.5%, P 0.001). On an echocardiogram, left ventricular dysfunction was seen more in subjects of Group II (n = 73, 33.8% vs. n = 27, 28.7%). Only a screening echocardiogram was performed in most subjects of Group II (n = 42, 19.4% vs. n = 11, 11.7%). Medical line of management (n = 167, 77.3% vs. n = 59, 69.2%) was given mostly in the Group II. There was a higher use of use of angiotensin-converting enzyme inhibitors (n = 4, 1.9% vs. n = 0, 0%), antiplatelets (n = 149, 69% vs. n = 62, 65.9%), heparin (n = 144, 31.5% vs. n = 29, 30.9%), and statin (n = 144, 66.7% vs. n = 59, 62.8%) among Group II. Coronary angiogram (n = 13, 13.8% vs. n = 13, 6%, P = 0.014) and percutaneous transluminal coronary angioplasty (n = 13, 13.8% vs. n = 13, 6%, P = 0.045) was more in Group I.

More subjects were stabilized with medication (n = 167, 76.4% vs. n = 59, 62.5%), and most of them succumbed to death (n = 29, 13.4% vs. n = 12, 12.8%) in Group II during the hospital admission. Aborted cardiac arrest was seen more among Group I (n = 8, 8.5% vs. n = 1, 0.5%, P < 0.001). During hospital admission, majority of the subjects in Group II had mild-to-moderate cognitive impairment (n = 80, 39.6% vs. n = 21, 23.3%, P = 0.014) and moderate-to-severe cognitive impairment (n = 37, 18.3% vs. n = 16, 17.8%, P = 0.014) compared to Group I.

After 30 days, the majority of them succumbed to death in Group II (n = 36, 19.3% vs. n = 15, 18.3%). There was also an increase in mild to moderate (n = 29, 19.2% vs. n = 6, 9%, P 0.057) and moderate to severe (n = 11, 7.3% vs. n = 2, 3%, 0.057) cognitive impairment in Group II as shown in [Table 3]. After 6 months in Group II, there was a higher number death (n = 27, 17.9% vs. n = 7, 10.4%), as shown in [Table 4]. More number of subjects had mild to moderate (n = 17, 13.7% vs. n = 4, 6.7%) and moderate to severe (n = 5, 4% vs. n = 0, 0%) cognitive impairment in Group II.{Table 3}{Table 4}


Summary of findings

In this prospective study, we observed that, following a development of ACS after a hospital admission, there was a prolongation of hospital stay. Majority of them were male subjects due to their lifestyle habits leading to ACS and most of them had a past history of systemic hypertension. Most of the subjects were on Lipid-Lowering agents before admission. Subjects with acute kidney injury developed ACS more frequently and majority of them were treated medically without any intervention. The most common type of ACS was non-ST elevation type, and serial troponin levels were raised in majority of the subjects. Regional wall motion abnormality was seen in most subjects in the screening Echocardiogram. Most of them received a Cardiology consultation, but only few patients underwent a Coronary intervention. Most of them were stabilized with medication, and the most prescribed medication was antiplatelets. Optimum medical management was not given to a reasonable number of subjects due to their current medical condition, adverse affects of the drug, lack of specialty consultation, and Cognitive impairment during an ACS. Majority of the subjects had an altered mental status during admission due to the disease process and required a reassessment of cognitive function.

There was a decline in cognition among the subjects after 30 days and 6 months which maybe attributable to the hospitalization, decline in medical condition, multiple medications, decline in functional status, frailty, and depression. Repeat hospitalization was also required for a significant number of subjects. At the end of 6 months, only 124 subjects survived out of 216 (57.4%), showing that there is a high risk of mortality among these subjects.

Comparison with prior studies

Baseline characteristics

The mean age of the subjects admitted to the hospital for noncardiac causes in the present study (72.1 ± 7.4 years) was similar to that reported in a study conducted in Barcelona, Spain[7] on ACS in elderly patients admitted with community acquired pneumonia (73.1 ± 14 years) showing an increase in days of admission with increase in age. Male subjects (73.1%) outnumbered females (26.9%) which is similar to a study (71.7% male) conducted in São Paulo, Brazil[8] on ACS in subjects following a noncardiac surgery. The mean length of hospital stay was 10.34 days, similar to 12.3 days in the study conducted in San Carlos, Spain on hypokalemia leading to ACS in the elderly patients[9] showing that there is an increase in the hospital stay due to the development of ACS after admission. The medication most commonly used before admission was Lipid-lowering agents (n = 135; 62.5%). The highest number of subjects taking Lipid lowering agents was observed in the study (42.7%) conducted in Uppsala, Sweden[10] on ACS in older adults admitted with atrial fibrillation. Subjects developing ACS after a Lower respiratory tract infection was 11.3% which was similar to 12% in Louisville, USA[11] on subjects admitted with community acquired pneumonia. Subjects developing ACS after Sepsis was 16.5% similar to 26% in Kentucky, the USA[12] on ACS developing in hospital in patients admitted with community-acquired pneumonia. 8.1% developed ACS after a stroke which was lower compared to a study (27%) done in Trondheim, Norway.[13] Seizure as a risk factor for developing an ACS was seen in 13.5% of subjects in this study compared to 6.7% in a study conducted in Beirut, Lebanon.[14] Anemia as a risk factor for developing ACS was seen in 14.2% of the subjects which was lower compared to a study (20.4%) done in Edinburgh, the UK on anemic subjects developing ACS after a noncardiac surgery.[15] The risk for developing an ACS was highest among elderly patients having an acute kidney injury in this study (27.1), which was higher when compared to 16% observed in a study in Saudi Arabia[16] on acute kidney injury developing in Chronic kidney disease patients. Subjects developing ACS with a risk of hyperkalemia was 2.3% compared to 4.5% and hypokalemia was 2.3% compared to 10.1% in a study conducted in San Carlos, Spain[17] on Serum potassium levels and the risk of developing ACS. Both hypo and hyperkalemia had an increased mortality after 30 days and 1 year. Association of hyponatremia with the development of ACS was seen in only 1.6% of patients in Kfar Saba, Israel[18] compared to 9% in the present study. Repeat ACS and all-cause mortality were seen mostly in subjects with hyponatremia compared to controls in that study. The risk of developing ACS after a Neurosurgery was 5.9% in a study conducted in Ontario, Canada[19] compared to 1% in the present study. Abdominal surgeries had a risk of 20.8% in a study conducted in São Paulo, Brazil[8] compared to 1.9% in the present study and post orthopedic surgeries 8.3% of subjects had an ACS compared to 2.9% in the present study. An elevated troponin levels after a Non-cardiac surgery, irrespective of the presence of ischemia, independently worsened the mortality after 30 days in these studies.


Medical management was given for 90.3% of the subjects in the present study. Angiotensin receptor blockers were given only for 15.7% of patients in this study compared to 78.3% given in a similar study conducted in São Paulo, Brazil[8] on ACS after a noncardiac surgery. ARB/ACE inhibitors were not given to majority of the subjects due to the development of hypotension, acute kidney injury, and hyperkalemia during hospital stay among these sunjects. Beta-blockers were given for 57.4% of the subjects compared to 42.1 in a study done in Japan on in-hospital ACS in hypokalemic subjects.[9] Beta-blockers were withheld in the rest of them due to the risk of developing hypotension. Antiplatelets were given to 69% compared to 63.2% in the study conducted in Dallas, TX, USA[20] on ACS in Cirrhosis subjects. They were not given in the rest of the subjects due to high risk of bleeding and anemia during admission. Heparin was given only to 68% compared to 86.7% given in a similar study conducted in São Paulo, Brazil[8] on ACS after a Non-cardiac surgery due to anemia during admission and high risk of bleeding in these subjects. Statins were given to only 66.7% of the subjects compared to 98.3% given in a similar study conducted in São Paulo, Brazil.[8] This was mostly due to deranged Liver function tests and lack of specialty consultation during an ACS in these subjects. Coronary angiogram was done in 6% of the subjects followed by PTCA compared to 33% CAG and 19% PTCA in a study conducted in Boston, USA[21] among subjects who developed ACS during admission for AKI. This was mostly due to a lack of specialty consultation during an ACS in these subjects. The coronary intervention was done for 6% of the subjects compared to 11.9% in the Kerala ACS registry. A palliative line of management was given to 3.7% of the subjects which was not shown in any of the literature. Optimum management was not given to a considerable number of subjects due to their current medical condition, adverse affects of the drug, and lack of cardiology consultation during an ACS.

Clinical outcome

One subject (0.5%) developed stroke in hospital similar to the study conducted in Uppsala, Sweden[22] on ACS in subjects admitted with Atrial fibrillation. Another subject had an aborted cardiac arrest (0.5%) in hospital compared to the study (1.8%) conducted in Dallas, TX, USA[20] on ACS in Cirrhosis subjects. In-hospital mortality was 13.4%, compared to a study (12.7%) done in Sydney, Australia[23] on ACS in stable dialysis subjects and to the study (15%) conducted in São Paulo, Brazil[8] on ACS after a noncardiac surgery. At the end of 30 days, 4.3% of the subjects developed an ACS similar to the study (10%) conducted in São Paulo, Brazil[8] on ACS after a noncardiac surgery. Total deaths after 30 days was 19.3%, similar to the study (16.1%) done in Sydney, Australia[23] on ACS in stable dialysis subjects.

In the literature search of 27 studies, the follow-up was done after either 30 days or 1 year. No study had a follow-up period of 6 months, and hence the data of this study were compared to the outcome after 1 year. At the end of 6 months, 4.6% of the subjects developed a repeat myocardial infarction in this study compared to the study (3.8% after 1 year) conducted in Kfar Saba, Israel[23] on hyponatremia as a risk factor for developing ACS. Total deaths were 17.9% in our study compared to 3.6% (after 1 year) in the study conducted in Uppsala, Sweden.

Cognitive assessment

None of the studies in the literature search conducted an assessment of cognition among elderly patients who were hospitalized due to ACS or who later developed an ACS. In this study cognitive assessment was done using Montreal cognitive assessment tool. Gu et al.[24] observed that at the time of admission, elderly patients with NSTEMI had a 48% prevalence of cognitive impairment. 70.8% of them had mild impairment compared to 20.8% in this study, 23.8% had moderate compared to 16.2% and 5.4% had severe cognitive impairment, compared to 17.1%. Cognitive impairment was high as elderly patients were delirious during hospital admission due to multiple factors.

The majority of the elderly patients had cognitive impairment during admission and Cognitive decline during follow-up after 30 days and 6 months in this study compared to 35.1% decline in cognition after 1 year in patients admitted with NSTEMI[24] in Newcastle, UK.

Strengths and limitations of this study

The main strength of this study is that none of the previous literature focused on the Geriatric aspect of cognitive status of the elderly patients getting admitted for ACS or later developing an ACS after hospitalization. The study also considers the risk factors, the level of guideline-based treatment, and outcome among these patients. The major limitation of this study was that it was conducted in a single tertiary care center over a small cohort, and the samples were obtained only for 4 months. Due to the same, the exact burden of ACS developing in noncardiac illnesses in the community could not be identified. The elderly require a long-term follow-up period, but in this study, it was limited to 6 months.


The observations from this study suggest that there is a high proportion of elderly patients who develop an acute coronary event in the hospital and deteriorate due to it. Optimum management is withheld from most of these subjects due to their current medical condition and the adverse affects of the drugs. This study highlights that clinicians must be vigilant for the development of cardiac complications when an elderly patient is admitted to the hospital, as early detection and optimum medical management would be very beneficial to these subjects. Age should not be the reason for withholding procedures and interventions which are lifesaving. The plan of management should be individualized based on risk versus benefit. Clinicians must consider the assessment of cognition and take measures to prevent Cognitive decline as it influences the clinical outcome. Clinical trials should include elderly patients proportionate to their prevalence among the treated population. In the coming years, the burden of ACS and Cognitive decline among elderly patients is only expected to increase, and this can lead to an adverse impact on the social care and health economics. But, with the above efforts, older adults can achieve a better outcome following an ACS.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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