Attrition change between start and end of session. Note that this almost certainly includes some attrition not related to the ongoing war, but most of it should be attributable to the war.
(First number is attrition losses at end of session, second is at start, third is the difference between the two)
Western Alliance:
Canapés: 1 286 625 - 413 812 = 872 813
Imperium: 1 293 651 - 632 539 = 661 112
Aquitaine: 341 957 - 253 756 = 88 201
De Raaf: 370 065 - 292 168 = 77 897
Total: 3 292 298 - 1 592 275 = 1 700 023
Eastern Alliance:
Neva-Luki: 1 162 527 - 609 973 = 552 554
Tragulia: 317 433 - 144 087 = 173 346
Kuba Luba: 364 694 - 259 347 = 105 347
Phrygia: 267 027 - 197 912 = 69 115
Horde: 236 275 - 202 984 = 33 291
Total: 2 347 956 - 1 414 303 = 933 653
So 1.7m vs. 0.93m. Definitely a significant disparity, but not nearly as significant as the war overview makes it appear.
Combined with battles, this makes the total death tolls 5.8m for the Western Alliance, and 3.4m for the Eastern Alliance.
As a followup, attrition incurred this session:
Western Alliance:
Canapés: 1 919 780 - 1 286 625 =
633 155
Imperium: 2 055 264 - 1 293 651 =
761 613
Aquitaine: 435 045 - 341 957 =
93 088
De Raaf: 388 048 - 370 065 =
17 983
Total: 4 798 137 - 3 292 298 = 1 505 839
Eastern Alliance:
Neva-Luki: 1 565 062 - 1 162 527 =
402 535
Tragulia: 390 181 - 317 433 =
72 748
Kuba Luba: 454 433 - 364 694 =
89 739
Phrygia: 298 408 - 267 027 =
31 381
Horde: 255 727 - 236 275 =
19 452
Total: 2 963 811 - 2 347 956 = 615 855
All told, that means 3 205 862 men died from attrition on the Western side during the two sessions.
1 549 508 on the Eastern side.
Nevermind all those who fell in battle.