Use and diagnostic value of liver enzyme tests in the emergency department and subsequent heart failure diagnosis: a retrospective cohort study

OBJECTIVES: To determine (1) if liver function tests (LFTs) are ordered in the emergency department (ED) in patients with suspected acute decompensated heart failure (ADHF) and (2) if the pattern of LFT abnormalities are meaningfully associated with a discharge diagnosis of ADHF among patients for whom these tests were ordered. SETTING: We conducted a single-centre retrospective cohort study of patients with suspected ADHF who were seen in an academic tertiary ED using electronic medical records. PARTICIPANTS: All ED patients admitted with suspected ADHF from January 2017 to May 2018, defined as any patient who had a brain natriuretic peptide (BNP) ordered. PRIMARY OUTCOME: The primary outcome was ADHF diagnosis at discharge. RESULTS: In 5323 ED patients with suspected ADHF, 60% (n=3184) had LFTs ordered; 34.6% were abnormal. Men comprised 56% of patients with abnormal LFTs and the average age was 67 years. The odds of a final diagnosis of ADHF in the univariate analysis was 59% higher in patients with abnormal LFTs (OR=1.59, (95% CI 1.35 to 1.87) p<0.001) and remained significant though attenuated after adjusting for BNP, race and ethnicity and age (ORadj=1.31 (95% CI 1.09 to 1.57), p=0.004). Likelihood ratios for abnormal and normal LFTs were 1.2 (95% CI 1.21 to 1.28) and 0.76 (95% CI 0.68 to 0.84), respectively. CONCLUSIONS: A significant proportion (40%) of patients with suspected ADHF was missing LFTs in their ED workup. Among patients with LFTs, abnormal LFTs are associated with discharge diagnosis of ADHF after accounting for potential confounders, but their diagnostic value was relatively low. Future prospective studies are warranted to explore the role of LFTs in the workup of ADHF.