Table 1 Characteristics of study population according to allocation to transfusions with filtered or non-filtered red blood cells and analysed group

Analysis group (n=1051^*)
Non-filtered (n=526)
Filtered (n=525)

No (%) of women
163 (31)
168 (32)

Mean (SD) age (years)
67 (11.0)
66 (11.5)

No (%) of patients transfused
278 (53)
267 (51)

Median units/patient (25th-75th centiles)
1 (0-4)
1 (0-4)

Mean duration of surgery (min)^*
210
205