Integrating frailty and acute illness severity scoring for risk stratification in acute geriatric care: Review and practical guide

Figure 2 The synergistic 2 × 2 risk stratification matrix. This conceptual model illustrates the prognostic value of intersecting baseline biological reserve (Y-axis) with acute physiological derangement (X-axis). Baseline reserve is stratified by the Clinical Frailty Scale (CFS)[4,72], dichotomized into low frailty (CFS 1-4) and high frailty (CFS 5-9). The X-axis represents an escalating gradient of acute illness severity, categorized as low acute severity [National Early Warning Score 2 (NEWS2) 0-4; Sequential Organ Failure Assessment (SOFA)/quick SOFA (qSOFA) 0-1] or high acute severity (aggregate NEWS2 ≥ 5 or a single ‘Red’ parameter score of 3[52]; SOFA/qSOFA ≥ 2[45,47]). The background color gradient reflects the escalating risk of mortality and functional decline. The discordant quadrants identify critical clinical phenotypes: Masked Risk (where high frailty blunts physiological response, leading to “silent severity”) and Masked Resilience (where robust biological reserve allows for survival of severe acute insults, provided “pessimism bias” is avoided). CFS: Clinical Frailty Scale; NEWS2: National Early Warning Score 2; SOFA: Sequential Organ Failure Assessment; qSOFA: Quick Sequential Organ Failure Assessment.