Evaluation of a modified early warning system for acute medical admissions and comparison with C-reactive protein/albumin ratio as a predictor of patient outcome

Abstract

The modified early warning score (MEWS) was developed as a track and trigger tool for the prompt identification of seriously ill patients on an acute medical ward. This paper examines its value in the setting of an acute medical admissions unit (MAU) and compares it to biochemical markers of acute and chronic disease. Three hundred unselected acute admissions to the MAU of the Queen Elizabeth Hospital, Gateshead, were assessed. Correlations between MEWS score and C-reactive protein (CRP) and albumin separately were assessed, and then the relationship between MEWS and the CRP/albumin ratio across the age spectrum was examined. The findings demonstrated a strong correlation between the MEWS score and CRP/albumin ratio (r=0.88, p<0.001) across the whole age spectrum. Length of stay correlated poorly with MEWS (r=0.08) and CRP/albumin ratio (r=0.15). Overall mortality was 5% and was predicted by both tools, with a MEWS score of >4 (relative risk (RR)=7.8) outperforming a CRP/albumin of >2 (RR=2.6). MEWS remains the gold standard for assessing outcome in acute medical admissions, but does have limitations in the elderly (those aged over 70 years). A raised CRP/albumin ratio was less sensitive for overall mortality than MEWS. It did, however, appear to be of greater value in the elderly, especially in those with acute exacerbations of chronic disease. Neither test accurately predicted length of stay.