Figure 1.

Increased alternative complement pathway activity is associated with decreased 30-day mortality and increased 1-year survival. (A) Scatter plot of classical pathway function (CH50) (U/ml serum; median, 130; interquartile range, 90–179) and alternative pathway function (AH50) (U/ml serum; median, 169; interquartile range, 136–204) values and (B) frequency distribution of AH50 values (grouped by increments of 50 U/ml serum; median value displayed) of serum prospectively collected from 321 consecutively enrolled critically ill patients at the time of enrollment. Normal value ranges are supplied by the manufacturer. (C) Probability of ICU mortality as a function of batch-adjusted AH50 (P = 0.015). (D) Patient survival from index ICU admission date by AH50 grouped by relationship to median (hazard ratio, 0.59 [95% confidence interval, 0.41–0.87]). Survival estimates are adjusted for AH50 batch effect, patient age, sex, sequential organ failure assessment score, chronic liver disease, and presence of active neoplasm. For AH50 less than median (n = 159), a single patient died within 24 hours of ICU admission and was therefore removed from this analysis rather than allocating an arbitrary duration of follow-up.