Consider Age When Treating BP in Patients with Kidney Disease

In veterans with incident chronic kidney disease (CKD), systolic blood pressure (SBP) is associated with poorer outcomes, but the effect is different in older versus younger patients, according to a new study. The association of higher SBP with adverse outcomes is present but markedly reduced in older individuals, especially in those aged 80 years and older.

“Hypertension treatment guidelines, such as JNC 8, recommend slightly higher BP targets when treating elderly patients,” explained lead study author Csaba Kovesdy, MD, of the division of nephrology, University of Tennessee Health Science Center. “Patients with CKD have been excluded from most hypertension treatment trials, hence the BP treatment goals in this group are mainly derived based on extrapolations. Even less is known about the effects of age on the association of BP with mortality and various other clinical outcomes in patients with CKD.”
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From among 339,887 patients with an incident estimated glomerular filtration rate below 60 mL/min/1.73m², the researchers examined associations of SBP and diastolic blood pressure (DBP) with all-cause mortality, incident coronary heart disease (CHD), ischemic strokes, and end-stage renal disease (ESRD) from the time of developing CKD until the end of follow-up (July 26, 2013, for mortality, CHD, and stroke; December 31, 2011, for ESRD) in multivariable-adjusted survival models categorized by patients’ age.

A total of 300,424 patients 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, while DBP showed no consistent association with either. SBP levels above 140 mm Hg were associated with higher incidence of all examined outcomes but with an incremental attenuation of the observed risk in older compared with younger patients (P < .05 for interaction). The adjusted hazard ratio and 95% confidence interval associated with SBP of 170 mm Hg and above (compared with 130-139 mm Hg) in patients younger than 50, 50-59, 60-69, 70-79, and 80 years and older were 1.95 (1.34-2.84), 2.01 (1.75-2.30), 1.68 (1.49-1.89), 1.39 (1.25-1.54), and 1.30 (1.17-1.44), respectively.

The risk of incident CHD, stroke, and ESRD was incrementally higher with higher SBP levels in patients younger than 80 but showed no consistent association in those 80 and older (P < .05 for interaction for all outcomes).

“Our results reinforce that treatment of hypertension in younger patients with CKD toward targets recommended by current clinical guidelines is paramount in order to improve outcomes,” Kovesdy said. “In very elderly patients with CKD, a more cautious BP-lowering strategy may be reasonable. Use of the higher BP targets recommended for elderly individuals may be reasonable.”

For future research, he is actively examining racial differences in outcomes and the effects of various treatment modalities in large cohorts of people with and without CKD.

—Mike Bederka

Reference:

Kovesdy CP, Alrifai AZA, Gosmanova EO, et al. Age and outcomes associated with BP in patients with incident CKD [published online April 21, 2016]. Clin J Am Soc Nephrol. doi:10.2215/CJN.08660815.