Management and Outcomes of Patients Admitted to Coronary Care Units, Depending on Degree of Frailty and Comorbidities

Background Patients less than 80 years of age, who suffer a myocardial infarction (MI) are usually (>90%) offered an early invasive strategy including coronary angiography possibly followed by intervention, preferably percutaneous coronary intervention (PCI). Among non ST-elevation myocardial infarction (NSTEMI) patients, 80 years of age or over, only approximately 40% receive an invasive approach in Sweden, since the majority are handled in a conservative way, i.e. with medical treatment only. Furthermore, as with pharmacological treatment, there is a large variation between Swedish counties regarding the choice of strategy for the treatment of elderly (80+) patients with NSTEMI with an even larger variation between acute hospitals ranging from 20% to 90 %.

The Swedish national guidelines for heart disease have emphasized that the patient's biological age, i.e. the patient's biological status and expected length of life, is crucial for decision-making. The Clinical Frailty Scale (CFS) is a global clinical measure of biological age, mixing co-morbidity, disability and cognitive impairment. The investigators have previously reported the potential importance of frailty for short-term (1 month) and medium-term outcome (1 year) in a NSTEMI population. However, published data on the role of frailty´s prognostic value, its capacity to predict adverse effects including complications, and the potential to guide clinical decision-making for elderly patients with myocardial infarction are scarce. Similarly, there is a lack of knowledge of how different patterns of comorbidity burden might influence rational decision-making.

Aims To explore the association between frailty and treatment patterns in cardiac care To study the association between outcomes and degree of frailty, with and without comprehensive adjustment for differences in baseline characteristics.

To study how treatment benefits for patients admitted to coronary care units differ in patients depending on comorbidities and frailty.

Hypothesis The investigators hypothesize that frailty is independently associated with worse outcomes, including mortality, readmissions and complications.

Methods and material An observational, register based, multicentre study. Inclusion criteria: Patients consecutively included in the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART) registry. Exclusion criteria: None.

SWEDEHEART is a national quality registry collecting information on all patients hospitalized with MI or suspected MI. All 72 Swedish hospitals with acute coronary care contribute with data. Briefly, information is collected prospectively about individual patients' medical history, treatment before admission, management during hospital stay, treatment at discharge, and diagnoses. Approximately 20.000 patients diagnosed with MI are included in this register per year. From January 1st 2020 frailty (CFS) is a mandatory variable in the registry. However, as a pilot project to ensure feasibility, five hospitals began to register frailty November 1st, 2017. For the investigators initial analyses data will be used from the pilot study to assess the association between CFS level and outcomes. The data extraction will be done by one of the monitors of the SWEDEHEART registry. After about two years the investigators will extract data prospectively entered into the registry.

The frailty instrument The crucial study instrument CFS is a 9-point scale. It has good predictive validity and prognostic power, is relying on clinical judgment, and is relatively easily used in clinical practice. Since the scale includes several degrees it can be considered to be particularly appropriate for risk stratification, and accordingly it has been used for this purpose. The investigators have got the instrument owner´s permission to use this scale.

The case record form (CRF) focus on demographic and clinical patient characteristics registered in the SWEDEHEART, particularly those which are supposed to be potential confounders when testing the hypothesis: chronological age, gender, cardiovascular risk, diabetes, heart failure, renal insufficiency, other co-morbidities, including the Charlson Comorbidity Index (CCI), previous MI, medications, ejection fraction, and the classification of MI. Cardiovascular risk will be assessed according to the Global Registry of Acute Coronary Events (GRACE) risk score (GRS). Results from echocardiography, ECGs, laboratory testing and registration of anthropometric data will be included according to routine practice within the frame of SWEDEHEART.

Follow-up of cohorts of invasively or conservatively treated patients with different stages of frailty will be done one, three, six, 12, 24 and 36 months after the inclusion point respectively.