Systolic BP and Mortality in Older Adults with CKD

Background and objectives Optimal BP targets for older adults with CKD are unclear. This study sought to determine whether a nonlinear relationship between BP and mortality-as described for the broader CKD population and for older adults in the general population-is present for older adults with CKD. Design, setting, participants, & measurements A cohort of 21,015 adults age 65-105 years with a moderate or severe reduction in eGFR (<60 ml/min per 1.73 m(2)) were identified within the Kaiser Permanente Northwest Health Maintenance Organization population. The relationship between baseline systolic BP (SBP; <= 120, 121-130, 131-140, 141-150, >150 mmHg; referent, 131-140 mmHg) and all-cause mortality across age groups (65-70, 71-80, and >80 years) was examined; patients were followed for up to 11 years after cohort entry. Results The median times at risk were 3.15 years, 3.53 years, and 2.76 years for adults age 65-70, 71-80, and >80 years, respectively. Mortality during follow-up was 19.6% for those age 65-70 years, 33.4% for those age 71-80 years, and 55.7% for those age >80 years. The relationship between SBP and mortality varied as a function of age. The risk of death was highest for patients with the lowest SBP in all age groups. Only among adults age 65-70 years was an SBP >140 mmHg associated with a higher risk of death compared with the referent category. Patterns of age modification of the relationship between SBP and mortality were consistent in all sensitivity analyses. Conclusions In a cohort of older adults, the relationship between SBP and mortality varied systematically with age. A relationship between higher SBP and mortality was present only for younger members of this cohort and not for those older than 70. These results raise the question of whether the relative benefits and harms of lowering BP to recommended targets for older adults with CKD may vary as a function of age.