SP302TIME-AVERAGED BLOOD PRESSURE AND OUTCOMES IN STAGE 3 TO 5 CHRONIC KIDNEY DISEASE PATIENTS

Abstract

INTRODUCTION AND AIMS: Several observational studies demonstrate low blood pressure (BP) levels seem related to higher risk of cardiovascular (CV) events, endstage renal disease (ESRD), or mortality in patients with chronic kidney disease (CKD). The latest results in Systolic Blood Pressure INTervention trial show that targeting systolic BP (SBP) of less than 120 mm Hg among 2646 patients with CKD was not as beneficial as those without CKD. These studies raise our concern that J-shaped relationship may exist in patients with CKD. However, most studies did not include patients with advanced CKD who have more comorbidities such as malnutrition. The purpose of this study is to investigate the relationships between time-averaged blood pressure and the clinical outcomes in patients with advanced CKD. METHODS: This prospective observational study enrolled 2340 CKD stage 3-5 patients between November 2002 and May 2009 and followed them until July 2010 or death. Standardized BP measurements were obtained by a standard mercury sphygmomanometer or a validated automated device in seated patients after a 10- minute rest. The average of the first 2 BP readings was recorded each visit. All BP records of each patient were averaged during the study period. Demographic, clinical, laboratory, and disease variables were measured. RESULTS: In 2340 CKD Stage 3-5 patients, ESRD occurred in 830 patients. In fullyadjusted Cox regression, J-shaped relationship existed between time-averaged SBP and ESRD: hazard ratio (HR) of time-averaged SBP <110 mmHg was 2.01 [95% CI 1.14- 3.57], and HR of time-averaged SBP ≥160 mmHg was 2.82 [95% CI 2.07-3.84], compared with reference group (time-averaged SBP 120-129 mm Hg). J-shaped relationship also existed between time-averaged SBP and cardiovascular events or all-cause mortality. The association between time-averaged SBP and malnutritioninflammation, defined as albumin <3.5g/dl and CRP >10mg/dl, was also J-shaped: odds ratio of time-averaged SBP <110 mmHg was 2.63 [95% CI 1.31-5.27], and odds ratio of SBP ≥ 160 mmHg was 1.63 [95% CI 1.10-2.41], compared with reference group. As for diastolic blood pressure (DBP), J-shaped relationship also existed between time-averaged DBP and CV events or all-cause mortality. For CV events, HR of time-averaged DBP <60 mmHg was 1.59 [95% CI 1.14-2.22], compared with reference group (time-averaged DBP 70-79 mm Hg). For all-cause mortality, HR of timeaveraged DBP <60 mmHg was 1.50 [95% CI 1.03-2.17], compared with reference group. As for pulse pressure, no J-shaped relationships were noted between timeaveraged pulse pressure and clinical outcomes. CONCLUSIONS: We demonstrated that J-shaped relationship of time-averaged SBP with ESRD, cardiovascular events and all-cause mortality and the J-shaped relationship of time-averaged DBP with cardiovascular events and all-cause mortality. There is no J-shaped relationship between time-averaged pulse pressure and clinical outcomes. Malnutrition-inflammation syndrome might be a possible factor associated with the impact of low BP in advanced CKD patients. (Table Presented).