Long-term Visit-to-Visit Blood Pressure Variability and Renal Function Decline in Patients With Hypertension Over 15 Years.
Chia YC, Lim HM, Ching SM. J Am Heart Assoc. 2016 Nov 7;5(11). PMID: 27821404
Hooi Min LIM (Malaysia)
1) Summarize your work in one sentence.
This study examined the relationship between visit-to-visit variability of systolic blood pressure (SBP) and decline in renal function in patients with hypertension as well as to determine the level of systolic blood pressure variability that is associated with significant renal function decline.
2) Summarize your findings in one sentence.
Our study showed that higher visit-to-visit variability of systolic blood pressure is associated with greater decline in renal function after adjustment for mean systolic blood pressure and the estimated cutoff values of SBP variability (standard deviation of SBP) for the onset of chronic kidney disease was 13.5mmHg in our cohort of patients.
3) Which were the more important methods you used in this work? If it is not a traditional method you can briefly explain the concept of that methodology.
We used a 15-year retrospective cohort study in a primary care clinic. It is clinically useful and relevant as it reflects the real life changes of kidney function in patients treated for hypertension. In this instance we looked at effects of BPV in treated patients. For clincial purposes we chose estimated glomerular filtration rate to study decline in kidney function as this measure is readily available and inexpensive to obtain. Subsequently eGFR slope was used to estimate the rate of renal function decline by fitting a linear regression line through the eGFR of each individual patient. To determine the level of SBP variability that is associated with renal function decline, we used receiver operating characteristics curve and Youden index.
4) What did you learn from this paper, what was your take-home message?
Look beyond the mean office systolic BP, an apparently normal SBP while on treatment for hypertension may still be associated with more rapid renal decline if the blood pressure variability is high. Our cutoff values of the blood pressure variability in this study may be a useful guide for clinicians who are managing patients with higher fluctuations of systolic BP. Efforts are needed to reduce the SBP variability in order to slow down the loss of renal function.