# Table 4 Incidence of acute kidney injury in critically ill pH1N1 patients using different definitions of baseline renal function

Primary analysis, with baseline glomerular filtration rate estimated as 75 ml/min/1.73 m2 Incidence Hospital mortality1, 2
(n = 562)
No AKI 220 (39.1) 28/216 (13.0)
None 181 (32.2) 21/178 (11.8)
Risk 39 (6.9) 7/38 (18.4)
AKI 342 (60.9) 85/329 (25.8)
Injury 129 (23.0) 20/125 (16.0)
Failure 213 (37.9) 65/204 (31.9)
Renal replacement therapy, n = 561 85 (15.1) 26/84 (31.0)
Injury 3 (0.5%) 3/3 (100)
Failure 82 (14.6%) 26/81 (31.0%)
Sensitivity analysis 1, assuming that first available serum creatinine is the baseline n = 537
No AKI 269 (50.1) 45/262 (17.2)
None 221 (41.2) 26/217 (12.0)
Risk 48 (8.9) 19/45 (42.2)
AKI 268 (49.9) 64/259 (24.7)
Injury 253 (47.1) 61/244 (25.0)
Failure 15 (2.8) 3/15 (20.0)
Sensitivity analysis 2, assuming that lowest observed serum creatinine at any time is the baseline n = 562
No AKI 218 (38.8) 27/214 (12.6)
None 194 (34.5%) 25/191 (13.1)
Risk 24 (4.2%) 2/23 (8.7)
AKI 344 (61.2) 86/331 (26.0)
Injury 118 (21.0%) 15/114 (13.2)
Failure3 226 (40.2%) 71/217 (32.7)
1. Data are presented as n (%).
2. 1 Denominators differ from the incidence column due to missing survival status (17/562 patients).
3. 2 In the primary analysis, mortality differed significantly across the 4 RIFLE categories of None, Risk, Injury, and Failure (p < 0.0001) and across the categories of Risk, Injury, and Failure (p = 0.003).
4. 3 For this analysis, patients who received RRT are assumed to have ‘Failure’.