Using inability to walk to predict in-hospital mortality in a high-income country – A comparison with the National Early Warning Score in a multicenter prospective cohort

BACKGROUND: Inability to walk (IATW) has predicted mortality in emergency units in low-income settings, but its value among inpatients in high-income countries is unknown. AIM: To evaluate the predictive accuracy of IATW for 30-day in-hospital mortality among inpatients in a high-income country, compare its performance with NEWS CRITICAL (the threshold for urgent review), and assess whether IATW provides complementary risk stratification when combined with NEWS. METHODS: All adult inpatients in four Swedish hospitals were prospectively examined in a multicenter point-prevalence assessment. IATW was defined as inability to walk five steps without physical assistance or walking aids. NEWS was calculated from contemporaneous vital signs. The primary outcome was 30-day in-hospital mortality. We computed sensitivity, specificity, predictive values, and likelihood ratios. Multivariable logistic regression assessed the association between IATW and mortality, adjusted for NEWS, age, and sex. RESULTS: Of 1842 patients, 59.9% were IATW-positive and 22.3% met NEWS CRITICAL (≥5 or any single-parameter score of 3). Mortality was 4.6%. IATW had higher sensitivity (86.9% vs 66.7%) but lower specificity (41.4% vs 79.8%) than NEWS CRITICAL; NPV was high for both (98.5% vs 98.0%). IATW was independently associated with mortality after adjustment for NEWS (OR 2.43, 95% CI 1.24-4.76; p = 0.009). Those both IATW-negative and with NEWS <5 (35.2% of the cohort) had 1.1% mortality. CONCLUSIONS: Inability to walk (IATW) is a bedside assessment that when negative identifies patients with low 30-day in-hospital mortality and provides complementary information to NEWS. Its low complexity, high sensitivity and low negative likelihood ratios support its use in clinical risk assessments.