Caram-Deelder C, et al. - This article was written with the objective to measure the relationship between red blood cell transfusion from female donors with and without a history of pregnancy and mortality of red blood cell recipients. Among patients who received red blood cell transfusions, receipt of a transfusion from an ever-pregnant female donor, compared with a male donor, was related to increased all-cause mortality among male recipients but not among female recipients. Transfusions from never-pregnant female donors were not related to increased mortality among male or female recipients. Further research is needed to replicate these findings, ascertain their clinical importance, and recognize the underlying mechanism.

Methods

• For this research, they designed a retrospective cohort study.
• This study was conducted on the first-time transfusion recipients at 6 major Dutch hospitals enlisted from May 30, 2005, to September 1, 2015; the final follow-up date was September 1, 2015.
• The primary analysis was the no-donor-mixture cohort (ie, either all red blood cell transfusions exclusively from male donors, or all exclusively from female donors without a history of pregnancy, or all exclusively from female donors with a history of pregnancy).
• The relationship amongst mortality and exposure to transfusions from ever-pregnant or never-pregnant female donors was examined utilizing life tables and time-varying Cox proportional hazards models.

Results

• The cohort for the primary examinations comprised of 31118 patients (median age, 65 [interquartile range, 42-77] years; 52% female) who received 59320 red blood cell transfusions exclusively from 1 of 3 types of donors (88% male; 6% ever-pregnant female; and 6% never-pregnant female).
• In this cohort, the number of deaths was 3969 (13% mortality).
• For male recipients of red blood cell transfusions, all-cause mortality rates after a red blood cell transfusion from an ever-pregnant female donor vs male donor were 101 vs 80 deaths per 1000 person-years (time-dependent “per transfusion” hazard ratio [HR] for death, 1.13 [95% CI, 1.01-1.26]).
• For receipt of transfusion from a never-pregnant female donor vs male donor, mortality rates were 78 vs 80 deaths per 1000 person-years (HR, 0.93 [95% CI, 0.81-1.06]).
• Among female recipients of red blood cell transfusions, mortality rates for an ever-pregnant female donor vs male donor were 74 vs 62 per 1000 person-years (HR, 0.99 [95% CI, 0.87 to 1.13]); for a never-pregnant female donor vs male donor, mortality rates were 74 vs 62 per 1000 person-years (HR, 1.01 [95% CI, 0.88-1.15]).