Elevated systolic blood pressure is associated with increased incidence of chronic kidney disease but not mortality in elderly veterans

The optimal blood pressure to prevent development of chronic kidney disease (CKD) and mortality in the elderly is unclear. Our objective was to determine the effect of differing levels of blood pressure on incidence of CKD and mortality in elderly veterans. This retrospective cohort study included 15,221 individuals >70 years of age without CKD (outpatient estimated glomular filtration rate >60 mL/min/1.73 m²) seen in the primary care clinic in the Veterans Affairs Health Care Upstate New York with Veterans Integrated Service Network 2 between 2001 and 2008. To examine the association of explanatory variables on hazard ratios for outcomes of interest, incident CKD, and death, competing risk analysis (with death as competing risk) was used for the analysis of incident CKD outcome, and time-dependent Cox model with CKD as the time-dependent covariate was used for the analysis of death outcome. The incidence of CKD was 16% over a median follow-up of 19 quarters. Compared with reference of systolic blood pressure of 130-139 mm Hg, there was an increased hazard of development of CKD with systolic blood pressure of 140-149 mm Hg or higher. As compared with a reference range of 130-139 mm Hg systolic blood pressure, the relative risk of mortality was higher in the range of 120-129 mm Hg systolic or less. The optimal achieved systolic blood pressure in elderly patients to prevent the development of CKD was <140 mm Hg. However, lowering the systolic blood pressure below 130 mm Hg was associated with increased mortality.