Clinical question: What is the association between detectable cardiac troponin (cTn) levels and outcomes in persons hospitalized with acute decompensated heart failure (ADHF)?
Background: There are millions of ADHF hospitalizations per year, and all-cause mortality and readmission rates are high. Efforts to better risk-stratify such patients have included measuring cTn levels and determining risk of increased length of stay, hospital readmission, and mortality.
Study design: Systematic review and meta-analysis.
Setting: Twenty-six observational cohort studies.
Synopsis: Compared with an undetectable cTn, detectable or elevated cTn levels were associated with greater length of stay (odds ratio [OR], 1.05; 95% CI, 1.01¬–1.10) and greater in-hospital death (OR, 2.57; 95% CI, 2.27–2.91). ADHF patients with detectable or elevated cTn were also at increased risk for mortality and composite of mortality and readmission over the short, intermediate, and long term. Reviewers eventually considered the overall association of a detectable or elevated troponin with mortality and readmission as moderate (relative association measure >2.0).
Meanwhile, few studies in this analysis showed a continuous and graded relationship between cTn levels and clinical outcomes.
Limitations of the review include arbitrarily stratifying groups by the level of cTn from assays whose lower limit of detection vary. The authors also admit the various associations are likely affected by several confounders for which they could not adjust because individual participant data were unavailable.
Finally, while acknowledging patients with chronic stable heart failure often have baseline elevated cTn levels, accounting for this in the analysis was limited.
Bottom line: A detectable or elevated level of cTn during ADHF hospitalization leads to worse outcomes both during and after discharge.
Citation: Yousufuddin M, Abdalrhim AD, Wang Z, Murad MH. Cardiac troponin in patients hospitalized with acute decompensated heart failure: a systematic review and meta-analysis [published online ahead of print February 18, 2016]. J Hosp Med. doi:10.1002/jhm.2558.
