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Fischer M, Weiss JW, Batten AJ, Bertenthal D, Do TP, Gupta I, Todd-Stenberg JA, O'Hare AM. The relationship between age, blood pressure, kidney function and mortality among a national cohort of Veterans. Poster session presented at: VA HSR&D Career Development Annual Meeting; 2011 Feb 16; National Harbor, MD.
Objectives: Hypertension and chronic kidney disease (CKD) are common high risk conditions in the elderly. The appropriateness of the current guideline recommended blood pressure (BP) goal in CKD ( < 130/80 mmHg) for older adults is not known. We examined the relationship between BP, estimated glomerular filtration rate (eGFR), and mortality in Veterans of different ages. Methods: We identified all Veterans with at least one outpatient serum creatinine (SCr) within VA between 10/1/2000 - 9/30/2001 and one BP measurement during the previous year. We examined the cross-sectional association between eGFR (ml/min/m2) and BP (mmHg) as a function of age and the longitudinal association between BP and death as a function of both age and eGFR. Results: Among 1,875,516 Veterans, the prevalence of systolic hypertension (SBP > 140) ranged from 19% to 40%, diastolic hypertension (DBP > 90) from 6% to 3%, and eGFR < 60 from 3% to 38% in adults < 45 years compared with those > = 75 years, respectively. In logistic regression analysis, while a greater likelihood of both systolic and diastolic hypertension existed at progressively lower levels of eGFR for adults < 45 years (p < 0.05), this relationship was progressively attenuated at older ages and no longer present in adults > = 75 years (p > 0.05). During 13.3 million person-years of follow up for death, the incident death rate was 4.5/100 person-years. In Cox proportional hazard analyses across all age and eGFR strata, a U-shaped relationship existed between SBP and death. The level of SBP associated with the lowest risk of death ranged from 120-139 mmHg in adults 45-59 years (p < 0.05) to 150-159 mmHg in adults > = 75 years (p < 0.05). Higher DBP was inconsistently associated with an increased risk of death across all ages. Implications: In older compared with younger Veterans, the prevalence of systolic hypertension was higher, but varied less as a function of eGFR. The association of SBP with death was nonlinear and varied substantially by age. Impacts: In older adults, a large discrepancy exists between the BP level at which mortality is lowest and the BP goal in current guidelines. Caution is warranted in pursuing currently recommended BP targets in older adults with CKD.