BACKGROUND: Acutely admitted medical patients are often fragile and in risk of future surgery. The biomarker soluble urokinase plasminogen activator receptor (suPAR) is a predictor of readmission and mortality in the acute care setting. We aimed to investigate if suPAR also predicts acute surgery, which is associated with higher mortality than elective surgery, and if it predicts post-operative mortality.

METHODS: A retrospective registry-based cohort study of 17,312 patients admitted to an acute medical unit in Denmark, from 18 November 2013 until 30 September 2015. The first admission with available suPAR was defined as the index admission, and patients were followed via national registries until 1 January 2016. The risk of acute surgery during the entire follow-up period as well as the 90-day post-operative mortality risk was modeled by Cox regression analyses adjusted for sex, age, C-reactive protein, and Charlson Comorbidity Index (Charlson Score).

RESULTS: Acute surgery was carried out on 2404 patients (13.9%) after a median of 45 days (interquartile range 5-186) following the index admission. Patients receiving acute surgery had higher baseline suPAR compared with patients receiving elective- or no surgery (p < 0.0001). The hazard ratio (HR) for acute surgery was 1.50 (95% confidence interval (CI): 1.42-1.59) for every doubling of the suPAR level in the adjusted Cox regression analysis. Death within 90 days occurred in 439 (18.3%) patients receiving acute surgery, and the adjusted HR for post-operative mortality was 1.73 (95% CI: 1.52-1.95).

DISCUSSION: Elevated levels of suPAR in acutely admitted medical patients were independently associated with increased risk of future acute surgery as well as with 90-day post-operative mortality.

TRIAL REGISTRATION: This retrospective registry-based cohort study was approved by the Danish Health and Medicines authority (reference no. 3-3013-1061/1). All processing of personal data followed national guidelines, and the project was approved by the Danish Data Protection Agency (reference no. HVH-2014-018, 02767).