Should impaired mobility on presentation be a vital sign?

Abstract

Introduction: Vital signs are routinely used to assess acutely ill patients, but they do not detect all patients at risk of death. This retrospective multicenter cohort study compares the prediction of death by impaired mobility with age, co-morbidities, and vital sign changes. Methods: On first assessment, patients from a combined cohort of 9684 Danish and Irish patients and a separate cohort of 1010 Ugandan patients were stratified by impaired mobility on presentation (IMOP), vital sign changes assessed by the National Early Warning Score (NEWS), the Charlson Co-morbidity Index, and age. Results: Fourteen percent of Danish and Irish patients had IMOP compared with 42% of Ugandan patients. The odds ratios of IMOP for 7-day mortality were similar for both cohorts (i.e. 11.8, 95% CI 5.8–24.0 for Ugandan patients versus 6.7, 95% CI 5.0–9.0 for Danish and Irish patients). Univariate analysis of Ugandan patients showed that none of the parameters tested (i.e. low blood pressure, pulse, elevated respiratory rate, hypothermia, low oxygen saturation, old age, and coma) had a statistically higher odds ratio for either 7-day mortality than IMOP. Multivariate logistic regression analysis of Danish and Irish patients also showed that none of these parameters or the Charlson Co-morbidity Index had a statistically higher odds ratio than IMOP for either 7-day or 30-day mortality. Conclusion: Immobility on presentation is a vital sign and predicts mortality for acutely ill patients independently of the traditional vital signs, age, and co-morbidities.