What is the clinical evidence from this study?

Study design: Cohort. Population: Acute myocardial infarction (n=294). Intervention: Frailty (Clinical Frailty Scale ≥5) vs. Non-frail (Clinical Frailty Scale ≤4). Primary outcome: 12-month all-cause mortality (HR 1.90, 95% CI 1.47-2.44, p=<0.001).

March 13, 2020Open Access

Frailty assessment and risk prediction by GRACE score in older patients with acute myocardial infarction

Q: What are the key findings of this study?

Frailty was associated with a nearly doubled hazard of 12-month mortality per point increase on the Clinical Frailty Scale (HR 1.90) and significantly enhanced the GRACE risk estimate.

Key Result

Frailty was associated with a nearly doubled hazard of 12-month mortality per point increase on the Clinical Frailty Scale (HR 1.90) and significantly enhanced the GRACE risk estimate.

Study Design

Type

Cohort (n=294)

Multicenter

Yes

Structured PICO

Does the addition of the Clinical Frailty Scale to the GRACE score improve 12-month mortality risk prediction in older patients with acute myocardial infarction?

Population

294 older adults (≥65 years) hospitalized with acute myocardial infarction across two UK centers, followed for 12 months to assess the prognostic value of frailty.

Exposure

Clinical Frailty Scale (CFS) assessment added to GRACE 2.0 risk score

Comparator

GRACE 2.0 risk score alone

Outcome

All-cause mortality in the 12 months following index admissionhard clinical

The Clinical Frailty Scale significantly improves 12-month mortality risk prediction when added to the GRACE score in older patients with acute myocardial infarction, largely by downgrading risk in non-frail patients.

Main Result

Hazard Ratio: 1.9 (95% CI 1.47–2.44)

Absolute Event Rate: 49% vs 9%

p-value: p=<0.001

Limitations

The study population was recruited for potential selection into a study of future care planning, likely resulting in a higher risk cohort than a general older cardiology population.
An age cutoff was chosen to enrich for the frailty measure, limiting the identification of younger patients with impairments.
The CFS did not independently predict hospital readmission, possibly due to competing mortality risk amongst frail patients.
Limited sample size in both the primary and external validation cohorts.

Abstract

BACKGROUND: Risk prediction after myocardial infarction is often complex in older patients. The Global Registry of Acute Coronary Events (GRACE) model includes clinical parameters and age, but not frailty. We hypothesised that frailty would enhance the prognostic properties of GRACE. METHODS: We performed a prospective observational cohort study in two independent cardiology units: the Royal Infirmary of Edinburgh, UK (primary cohort) and the South Yorkshire Cardiothoracic Centre, Sheffield, UK (external validation). The study sample included 198 patients ≥65 years old hospitalised with type 1 myocardial infarction (primary cohort) and 96 patients ≥65 years old undergoing cardiac catheterisation for myocardial infarction (external validation). Frailty was assessed using the Clinical Frailty Scale (CFS). The GRACE 2.0 estimated risk of 12-month mortality, Charlson comorbidity index and Karnofsky disability scale were also determined for each patient. RESULTS: Forty (20%) patients were frail (CFS ≥5). These individuals had greater comorbidity, functional impairment and a higher risk of death at 12 months (49% vs. 9% in non-frail patients, p < 0.001). The hazard of 12-month all-cause mortality nearly doubled per point increase in CFS after adjustment for age, sex and comorbidity (Hazard Ratio HR 1.90, 95% CI 1.47-2.44, p < 0.001). The CFS had good discrimination for mortality by Receiver Operating Characteristic (ROC) curve analysis (Area Under the Curve AUC 0.81, 95% CI 0.72-0.89) and enhanced the GRACE estimate (AUC 0.86 vs. 0.80 without CFS, p = 0.04). At existing GRACE thresholds, the CFS resulted in a Net Reclassification Improvement (NRI) of 0.44 (95% CI 0.28-0.60, p < 0.001), largely through reductions in risk estimates amongst non-frail patients. Similar findings were observed in the external validation cohort (NRI 0.46, 95% CI 0.23-0.69, p < 0.001). CONCLUSIONS: The GRACE score overestimated mortality risk after myocardial infarction in these cohorts of older patients. The CFS is a simple guided frailty tool that may enhance prediction in this setting. These findings merit evaluation in larger cohorts of unselected patients. TRIAL REGISTRATION: Clinicaltrials.gov; NCT02302014 (November 26th 2014, retrospectively registered).

Ask AI

Helpful

Bookmark

View Full Paper