Predialysis Systolic Pressure and Mortality

Abstract

Objective: This study aimed to verify the impact of predialysis systolic pressure (PDSP) on patients’ mortality. Design and method: We reviewed files of incident patients, in one reference center of hemodialysis, between January 2009 and June 2010. Arterial pressure was measured by sphygmomanometer before initiating the patient's first dialysis session. We considered: as “high PDSP” a SP equals or over 180 mmHg; as “low PDSP” a PS equals or less than 100 mmHg. Univariate and multivariate analysis were performed to study PDSP association with absolute mortality at five years. Odds ratio (OR) was subject to a 95% confidence interval. We used Kaplan Meier method for survival curves. Results: One hundred eleven patients were included. Sex ratio was 1.7 M/W. At dialysis initiation: mean age was 55 ± 14.9 years. Sixty nine patients (62%) were hypertensive; all of them were under antihypertensive agents. MAP, SP and DP were respectively 98.8 ± 16.3 mmHg, 139.4 ± 25.4 mmHg and 79.1 ± 14 mmHg. Mean urinary output was 1156 ± 542 ml/day and initial serum creatinine 887 ± 271 μmol/l. In univariate analysis, absolute mortality at five years was associated with low PDSP (p = 0.001, OR = 4.8). This association was pronounced among orderlies (p = 0.001) and diabetic patients (p = 0.001). High PDSP was also associated with absolute mortality at five years (p = 0.03; OR = 1.67). In multivariate study, neither low nor high PDSP were associated to mortality. Survival was decreased for patients with low PDSP (log-rank p = 0.001) (Figure 1) and high PDSP (log-rank p = 0.03) (Figure 2). Conclusions: These results suggest the presence of a “U” curve relationship between PDSP and mortality. Further studies, with larger populations, are needed to determine the potential use of low PDSP as a mortality risk factor.