Results
We reviewed 356 clinical records from patients with CKD who entered SSCKD between 2016 and 2018. We excluded 12 patients because they did not have complete laboratory tests and one who did not present a death date. Finally, we included 343 patients in the analysis. The mean age was 78.3 (± 11.9) years, and the median follow-up time was 2.45 years (2.08-3.08). In the population studied, the predominant gender was male, with 62.9% (n=216). Regarding comorbidities, 64.7% were found to have hypertension, while 30% have diabetes mellitus. On the other hand, the average of eGFR was 47.4 (± 10.5) ml / min / 1.73 m2and the ERC stage included 22 (6.4%) patients in stages 1-2, 311 (90, 7%) patients in stages 3a-3b and 10 (2.9%) patients in stages 4-5. Demographic and laboratory characteristics are shown in Table 1.
Regarding the exposure’s variables, 14.6% (n=50) had high NLR and 8.2% (n=28) high PLR. In total, 17.5% (n=60) died at the end of follow-up. Participants with elevated NLR had higher serum levels of alkaline phosphatase (114 vs 100 U/L; p=0.03) and platelets (260 vs 234 K/uL; p<0.01) than participants with normal NLR (Table 1). Participants with elevated PLR had a lower average age (72.6 vs 78.8 years; p<0.01), glutamic oxaloacetic transaminase (19 vs 23 U/L; p=0.02) and hemoglobin (11.2 vs 12.2 g/dL; p<0.01) compared to participants with normal PLR. In contrast, participants with elevated PLR had higher serum levels of neutrophils (4.5 vs 3.9 K/uL; p = 0.03) (Table 2).
The mortality of patients with high NLR was 28% compared to 15.7% of the group with normal NLR (p = 0.03). Likewise, mortality was 35.7% in those with high PLR and 15.6% in those with normal PLR (p=0.01). The mortality rate in the group with high NLR was 12.5 deaths per 100 person-years of follow-up, while in the group with high PLR, it was 16 deaths per 100 person-years of follow-up. Kaplan-Meier curves showed a statistically significantly worse survival function for participants with high NLR and PLR at the end of follow-up (Figure 1 and 2).
Mean age was higher in the group of the dead (81.9 vs 77.5 years; p <0.01) and there was more mortality in males (21.3 vs 11; p = 0.01). The most advanced stages of chronic kidney disease had higher mortality, 9.1%, 16.4% and 70%, respectively. In the laboratory profile, creatinine levels were higher in the dead group (1.4 vs 1.6 mg/dL; p<0.01). On the other hand, both hemoglobin (11.7 vs. 12.3 g/dL; p = 0.03) and albumin (4.0 vs. 4.2 mg/dL; p<0.01) had lower values in the dead group (Table 3).
In the crude analysis, the high NLR was significantly associated with all-cause mortality (HR = 2.01; 95% CI: 1.11-3.66). Likewise, the high PLR was significantly associated with all-cause mortality (HR = 2.58; 95% CI: 1.31-5.20) (Table 4).
In the multivariate model, after adjusting for age, sex, serum creatinine, chronic kidney disease stage, albumin and hemoglobin, the high NLR and PLR remained as an independent risk factor for all-cause mortality, (HR = 2.10; 95% CI: 1.11-3.95) and (HR = 2.71; 95% CI: 1.28-5.72); respectively (Table 4).