Accumulating evidence has shown that predialysis chronic kidney disease (CKD), or declined renal function, is an independent risk factor for death, cardiovascular events and stroke in the general population.1, 2, 3 Japan is rapidly becoming an aged society and the prevalence of CKD is high among the elderly.4 Accordingly, it is important to develop a therapeutic strategy for elderly patients with CKD.
As hypertension is a classical risk factor for CKD occurrence and progression, proper control of blood pressure (BP) could be regarded as a first-line therapeutic strategy. Unfortunately, the beneficial effect of strict BP control in the elderly is unclear. For example, very recently, the JATOS (the Japanese Trial to Assess Optimal Systolic Blood Pressure in Elderly Hypertensive Patients) study failed to show a beneficial (including renoprotective) effect of strict BP control (systolic BP <140 mm Hg).5
One possible hypothesis is that using home BP monitoring could be an effective strategy to determine the optimal BP level. Several reports have shown that BP measured at home has superior predictive value for mortality, cardiovascular events6 and stroke,7, 8 and screening value for asymptomatic cerebral ischemia9 and CKD.10 In addition, a previous study showed that home-measured BP is better than clinic-measured BP at predicting the progression of disease in ‘general’ CKD patients.11
In an article appearing in this issue, Okada et al.12 used home BP monitoring, and assessed the prognostic value of home BP (morning and evening) and casual BP for renal and cardiovascular outcome in elderly CKD patients (age ⩾70 years). Using the Cox proportional hazards model, Okada et al. showed that home (both morning and evening), but not casual, systolic BP was significantly associated with an increased risk of renal end point. The authors suggest that home BP monitoring may be useful for the detection of renal prognosis in elderly CKD patients. Results were confirmed not only by performing multiple measurements of home BP (7 days), but also by performing the same number of measurements as the casual BP (twice). Therefore, it is suggested that the superior prognostic value of home BP is not due to the number of measurements; however, other contributing factors may include the lack of the white-coat effect or the timing of BP measurement (in early morning or late evening).
Although this study failed to elucidate the optimal target level of home BP (probably owing to the small cohort size; n=104), it succeeded in suggesting that home-based BP control could improve the renal prognosis of CKD even in the elderly. The optimal home-measured BP and the putative suppression of CKD in the elderly by therapeutic intervention remain issues that must be elucidated by future studies.
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Terawaki, H. Home blood pressure monitoring, even by the elderly, may save a kidney. Hypertens Res 32, 1055 (2009). https://doi.org/10.1038/hr.2009.169
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DOI: https://doi.org/10.1038/hr.2009.169
