Age and Outcomes Associated with BP in Patients with Incident CKD

Abstract

Background and objectives Hypertension is the most important treatable risk factor for cardiovascular outcomes. Many patients with CKD are elderly, but the ideal BP in these individuals is unknown.Design, setting, participants, & measurements From among 339,887 patients with incident eGFR,60 ml/min per 1.73 m 2 , we examined associations of systolic BP (SBP) and diastolic BP (DBP) with all-cause mortality, incident coronary heart disease (CHD), ischemic strokes, and ESRD from the time of developing CKD until the end of follow-up (July 26, 2013, for mortality, CHD, and stroke, and December 31, 2011, for ESRD) in multivariableadjusted survival models categorized by patients' age.Results Of the total cohort, 300,424 (88%) had complete data for multivariable analysis. Both SBP and DBP showed a U-shaped association with mortality. SBP displayed a linear association with CHD, stroke, and ESRD, whereas DBP showed no consistent association with either. SBP.140 mmHg was associated with higher incidence of all examined outcomes, but with an incremental attenuation of the observed risk in older compared with younger patients (P,0.05 for interaction) The adjusted hazard ratios and 95% confidence intervals associated with SBP$170 mmHg (compared with 130-139 mmHg) in patients ,50, 50-59, 60-69, 70-79, and $80 years were 1.95 (1.34 to 2.84), 2.01 (1.75 to 2.30), 1.68 (1.49 to 1.89), 1.39 (1.25 to 1.54), and 1.30 (1.17 to 1.44), respectively. The risk of incident CHD, stroke, and ESRD was incrementally higher with higher SBP in patients aged ,80 years but showed no consistent association in those aged $80 years (P,0.05 for interaction for all outcomes). ConclusionsIn veterans with incident CKD, SBP showed different associations in older versus younger patients. The association of higher SBP with adverse outcomes was present but markedly reduced in older individuals, especially in those aged $80 years. Elevated DBP showed no consistent association with vascular outcomes in patients with incident CKD.

The Continued Quest for Optimal BP Targets in Older Adults with Kidney Disease

“…This study (12) identified an increased risk of mortality with lower diastolic BP (DBP; DBP,60 mmHg) but no association between higher levels of DBP (.80 mmHg) and examined outcomes; this finding is consistent with previous work by Kovesdy et al (13) and our group (14). The risk of isolated systolic hypertension increases as eGFR declines, and lower levels of DBP have been associated with increased risk of mortality and cardiovascular events (3,(15)(16)(17).…”

“…In a previous study of older adults with CKD, we also described a U-shaped relationship between SBP and mortality (increased risk of mortality with SBP.140 and ,130 mmHg compared with 130-139 mmHg) among adults ages 65-70 years old but found no increase in risk of death at higher levels of SBP for those ages $70 years old (14). In our previous analysis (14) and in this study (12), there was not a definitive increase in the relative risk of mortality for adults ages $80 years old when SBP was 140-149 or 150-159 mmHg (confidence intervals included unity). Kovesdy et al (12) expanded on this, however, via a more finely stratified analysis of higher SBP levels, which found an increase in relative risk of death even among those $80 years old when SBP was .160 mmHg.…”

“…In our previous analysis (14) and in this study (12), there was not a definitive increase in the relative risk of mortality for adults ages $80 years old when SBP was 140-149 or 150-159 mmHg (confidence intervals included unity). Kovesdy et al (12) expanded on this, however, via a more finely stratified analysis of higher SBP levels, which found an increase in relative risk of death even among those $80 years old when SBP was .160 mmHg. This suggests that a U-shaped relationship between BP and mortality was present even among the oldest participants but that the threshold where risk of death increases relative to SBP varied with age.…”

“…In a large retrospective cohort of United States veterans, Kovesdy et al (12) identified a U-shaped relationship between SBP and examined outcomes (mortality, incident coronary heart disease, incident stroke, and ESRD). Kovesdy et al (12) found that both SBP$140 and ,120 mmHg were associated with an increased risk of all examined outcomes compared with SBP5130-139 mmHg, but the magnitude of risk associated with a given level of BP was attenuated with advancing age. For example, when SBP was $170 mmHg, the hazard ratios for mortality were 2.01, 1.68, 1.39, and 1.30 for ages 50-59, 60-69, 70-79, and $80 years old, respectively.…”

“…In this issue of the Clinical Journal of the American Society of Nephrology, Kovesdy et al (12) add to the collective understanding of the relationship between BP and a wide range of clinical outcomes in older adults with incident CKD. In a large retrospective cohort of United States veterans, Kovesdy et al (12) identified a U-shaped relationship between SBP and examined outcomes (mortality, incident coronary heart disease, incident stroke, and ESRD).…”