P1495low Diastolic Blood Presure With Low Mean Corpuscular Hemoglobin Concentration Would Deteriorate Cardiovascular Mortality in the Patients With Maintenance Hemodialysis

Abstract

Background and Aims In dialysis patients, many literatures have shown the association between predialytic hypotension and poor prognosis. Particularly, decrease in diastolic blood pressure (DBP) will be involved myocardial injury because of reduced coronary blood-flow. Such myocardial damage would also be caused by decreased oxygen-supply capacity. Mean corpuscuar hemoglobin-concentration (MCHC) is a hemoglobin concentration per 1% hematocrit (Ht) and could be considered as an indicator of peripheral oxygen-supply. In several literatures, low MCHC had been associated with increased all-cause mortality in non-dialysis patients with congestive heart-failure. In dialysis patients with low Ht between 32 to 35%, low DBP and low MCHC could additively act on myocardial damage. In this study, we examined the relation between the stratified groups by DBP and MCHC and cardiovascular mortality using Yoshikawa clinic dialysis-database (YCD). Method A total of 407 dialysis patients registered in YCD enrolled in this study from April 2006 and on. The cut-off values (COVs) of predialytic DBP and MCHC on cardiovascular death (CVD) were determined from the Receiver Operating Characteristic (ROC) curve. According to these COVs, the whole cohort was divided into 4 groups, group HH (high DBP and high MCHC), group HL (high DBP and low MCHC), group LH (low DBP and high MCHC), and group LL (low DBP and low MCHC). Their survival analysis was estimated by the Kaplan–Meier method, and a log-rank test was used to examine the differences between the survival curves. The prognostic factors for CVD were extracted from background factors, including predialytic DBP, MCHC and above-mentioned grouping, using Cox-regression model. Results In 407 patients, mean predialytic DBP and time-averaged MCHC were 73.3 mmHg and 31.5 % respectively. During observation period of 5.1 years 163 patients died, among that 94 were CVD. The COVs of DBP and MCHC were 79 mmHg and 31.16 %, respectively. According to these COVs, 407 patients were divided into 64 of group HH, 65 of group HL, 171 of group LH and 107 patients of group LL. On the survival curve, the group LL had the highest mortality rate, followed by the group HL. The group HH showed the lowest mortality rate. In multivariate analysis, category variables LL and HL were extracted as prognostic factors for CVD. Their Hazard ratio were 1.960 and 3.863, respectively. Age, intradialytic hypotension, DBP, Kt/V, serum sodium, CRP and blood glucose were extracted as the other prognostic factors. Conclusion These results suggest that low MCHC level would deteriorate prognosis on dialysis patients with predialytic low-DBP. MCHC level could become a new treatment-target in the low DBP group in the future.