Combining the National Early Warning Score 2 with Frailty Assessment to Identify Patients at Risk of In-Hospital Cardiac Arrest: A Descriptive Exploratory Study

<i>Background and objectives:</i> In older and frail patients, in-hospital cardiac arrest (IHCA) is associated with high mortality. Early warning scores such as the National Early Warning Score 2 (NEWS2) are widely used to detect clinical deterioration, but their predictive accuracy in frail populations remains uncertain. This study aimed to assess whether integrating frailty measures with NEWS2 could better describe elderly IHCA patients. <i>Materials and Methods</i>: We conducted a single-center, retrospective observational study in adult and frail patients (≥18 years) admitted to medical and surgical wards of the University Hospital of Siena who experienced IHCA between January 2022 and January 2024. Data on demographics, such as last NEWS2 before IHCA, Clinical Frailty Scale (CFS), Barthel Index (BI), and Charlson Comorbidity Index (CCI) were retrospectively collected and analyzed. Patients were stratified into three categories, according to NEWS2: Stable (A), Potentially Unstable or Unstable (B), and Critical (C). <i>Results</i>: Seventy patients were analyzed (mean age 76.9 ± 11.0 years; 56% male). The mean pre-IHCA NEWS2 score was 6.0 ± 3.5, with 41% of patients classified as NEWS2-C, 48% classified as NEWS2-B, and 11% classified as NEWS2-A. The NEWS2-A category showed higher BI and lower CFS than NEWS2-B and NEWS2-C (<i>p</i> < 0.01), while CCI and age did not significantly differ. <i>Conclusions</i>: The association of NEWS2 with frailty scores could identify some elderly patients with limited pre-arrest physiological derangements but high frailty who suffered from IHCA. These findings provide descriptive insights that may inform monitoring strategies for "at-risk" elderly patients to help prevent IHCA.