Background: Higher total white blood cell counts (WCC) have been shown in the general population to be strongly and independently predictive of coronary heart disease and all-cause mortality. The aim of the present study was to evaluate the prognostic value of WCC in patients commencing peritoneal dialysis (PD).
Methods: A cohort of 323 patients (mean age 55.1 +/- 17.7 years, 54% male, 81% Caucasian) commencing PD at the Princess Alexandra Hospital between January 1, 1998 and March 31, 2003 were prospectively followed until death, completion of PD therapy, or otherwise to the end of the study (January 2, 2004), at which point data were censored. Individuals with failed renal transplants (N= 17) and those with acute infections at the time of PD onset (N= 12) were not included. A multivariate Cox's proportional hazards model was applied to calculate hazard ratios and adjusted survival curves for time to death or cardiac death, adjusting for baseline demographic, clinical, and laboratory characteristics.
Results: Median actuarial patient survival was 3.9 years [95% confidence interval (CI) 3.2-4.7 years]. The highest quartile of WCC (>9.4 x 10(9)/L) was significantly and independently associated with increased risks of both death from all causes [adjusted hazard ratio (HR) 2.27, 95% CI 1.09-4.74, P < 0.05] and cardiac death (HR 3.75, 95% CI 1.2-11.8, P < 0.05). Other adverse risk factors included older age, lower serum albumin, and the presence of coronary artery disease. Similar associations were found between mortality and PMN count, but not lymphocyte count.
Conclusion: Elevated baseline WCC or PMN count at the commencement of PD (in the absence of acute infection) strongly predicts all-cause and cardiovascular mortality. These data suggest that new PD patients with higher WCC may warrant closer monitoring and extra attention to modifiable cardiovascular risk factors.