[Severe bacterial infection: increased mortality in elderly women with low body weight taking drugs prolonging the QTc interval].

AIMS: Women have a higher risk of acquired long QT syndrome which could be of vital importance in severe bacterial infections when macrolides or fluoroquinolones are administered. This study evaluated whether age, drugs prolonging the QTc interval and body weight were additional influencing factors on mortality in the critically ill with respect to gender.
METHODS: In an exploratory investigation 204 intensive care unit (ICU) patients (78 f, 126 m, 61.1±16.1 years) with severe bacterial infections were studied (mortality probability model II(0) 49.1±28%). Antibiotic therapy was carried out following standard guidelines. In 65.2% of patients potentially QTc prolonging drugs were administered for ≥48 h. Body weight was ascertained on ICU admission.
RESULTS: By comparable severity of illness and comparable effect of antibiotic therapy, age, QTc prolonging drugs and less body weight showed significant effects on survival in women (p<0.001, 0.008 and 0.009, respectively). For women mortality increased with age ≥60 years (p=0.01). The division between survival versus non-survival was intensified by addition of QTc prolonging medication and body weight. As such a best risk assessment in women was achieved if age, QTc prolonging therapy and less body weight were combined (p<0.001). In a direct comparison to men, women with at least two of these factors had a significantly poorer outcome (OR 2.37; 95% CI 1.13-4.98; p=0.022).
CONCLUSIONS: Age, QTc prolonging drugs and lower body weight can additionally increase mortality in critically ill women. If negative outcome is attributed to a higher dosage, an adjustment for body weight must be carried out. Until now it should be considered whether it would be better to replace QTc prolonging antibiotics in routinely performed drug alternation in elderly lean women.