To determine the relationship between short-term mortality and intravenous morphine use in emergency department (ED) patients diagnosed with acute heart failure (AHF).
Consecutive AHF patients presenting to 34 Spanish EDs from 2011 to 2014 were eligible for inclusion. The subjects were divided into those with or without intravenous morphine treatment (M and WOM groups, respectively) during ED stay. The primary outcome was 30-day all-cause mortality, and secondary outcomes were mortality at different intermediate time points, in-hospital mortality, and length of hospital stay (LOS). We generated a propensity-score in order to match the M and WOM groups 1:1 according to 46 different epidemiological, baseline, clinical and therapeutic factors. We investigated independent risk factors for 30-day mortality in patients receiving morphine.
We included 6516 patients (mean age: 81 (SD 10) years; 56% women): 416 (6.4%) in the M and 6100 (93.6%) in the WOM group. Overall, 635 (9.7%; M:26.7%; WOM:8.6%) died by day 30. After propensity score matching, 275 paired patients constituted each group. M patients had a higher 30-day mortality (55 [20.0%] vs. 35 [12.7%] deaths; HR: 1.66; 95%CI: 1.09-2.54; p=0.017), which was directly related to glycaemia (p=0.013) and inversely related to the baseline Barthel index and systolic blood pressure (p=0.021) at ED arrival (p=0.021). Mortality was increased at every intermediate time point, although the greatest risk was at the shortest time (at 3 days: 22[8.0%] vs. 7 [2.5%] deaths; OR: 3.33; 95%CI: 1.40-7.93; p=0.014). In-hospital mortality did not increase (39 [14.2%] vs. 26 [9.1%] deaths; OR: 1.65; 95%CI: 0.97-2.82; p=0.083) and LOS did not differ between groups (median (IQR) in M: 8(7); WOM: 8(6); p=0.79).
This propensity score-matched analysis suggests that the use of intravenous morphine in AHF could be associated with increased 30-day mortality.