<b><i>Background:</i></b> Polycythemia has not been extensively studied for its impact on acute coronary syndrome (ACS) outcomes. A previous study reported only 30-day outcomes to be worse in these patients. <b><i>Methods:</i></b> Data from the ACS Israeli survey between 2000 and 2018 were utilized to compare between 3 groups of patients with ACS: anemic group (hemoglobin <12 g/dL for women and <12.5 g/dL for men), normal hemoglobin group, and polycythemic group (>16 g/dL and >16.5 g/dL, respectively). Measured outcomes included 30-day major adverse cardiac events (MACE comprising all-cause mortality, recurrent ACS, need for urgent revascularization, and stroke) and 1- and 5-year all-cause mortality. <b><i>Results:</i></b> Of 14,746 ACS patients, 10,752 (72.9%) had normal hemoglobin levels, 3,492 (23.7%) were anemic, and 502 (3.4%) were polycythemic. In comparison with normal and anemic patients, polycythemic patients were younger (55.9 ± 10.5 vs. 61.9 ± 12.4 and 71.1 ± 12.2 for anemic, respectively, <i>p</i> < 0.001 for both), more frequently men (93.8% vs. 81.3% and 63.1%, respectively, <i>p</i> < 0.001), and less likely diabetic or hypertensive. Upon adjustment to baseline characteristics, compared with normal hemoglobin, polycythemia was not independently associated with 30-day MACE or 1-year mortality, but it was independently associated with higher risk for 5-year mortality (HR 1.76, 95% CI: 1.19–2.59, <i>p</i> = 0.005). Similar results were observed after propensity score matching. <b><i>Conclusions:</i></b> Although younger and with fewer comorbidities, polycythemic ACS patients are at increased risk for long-term all-cause mortality. Further study of this association is warranted to understand the causes and possibly to improve the outcomes of these patients.
High-sensitivity troponin T and long-term adverse cardiac events among patients presenting with suspected acute coronary syndrome in Singapore
