Prolonged QTc Interval at Admission: A Hallmark of Poor Prognosis in Community-Acquired Pneumonia?

Abstract

<bold>Introduction:</bold> Cardiovascular complications during infectious pneumonias can signify a severe condition. Few studies have focused on investigating the prolongation of the QTc interval in hospitalized patients with community-acquired pneumonia (CAP). The objective of our study was to investigate the prolongation of the QTc interval calculated at admission in patients hospitalized for CAP. <bold>Methods:</bold> We conducted a prospective study involving 280 patients admitted for community-acquired pneumonia over a 3-year period from January 2020 to December 2023 at our Pulmonology department. Patients taking medications known to prolong the QT interval or presenting with hypokalemia or hypocalcemia at admission were excluded. The QTc interval is considered prolonged if its value exceeds 450 ms in men and 460 ms in women. <bold>Results:</bold> We enrolled 200 patients, with 120 (60%) men and 80 (40%) women. The mean age was 61.82±13 years. Cardiovascular history was present in 80 (40%) patients. Prolonged QTc interval was observed in 118 (59%) patients. Those with prolonged QTc required higher initial oxygen levels (8.78 vs. 3.22 liters/minute; p=0.04) and more often required critical care transfer (p=0.01). Biochemically, prolonged QTc correlated with CRP levels >100 mg/L (r=0.295; p=0.01) and elevated lactate dehydrogenase (r=0.423; P<10-3). The prolonged QTc interval, with a cut-off of 467 ms, predicted a hospital stay of more than ten days and was associated with pleural effusion (P<10-3). Remarkably, 106 patients (80%) had normal QTc at discharge. <bold>Conclusion:</bold> Our study demonstrates that prolonged QTc interval may serve as an early indicator of severity in CAP.