The nocturnal dip
There is a strong link between kidney disease and BP variations both in normal and hypertensive individuals that leads to the chicken or the egg conundrum of which came first when we manage our hypertensive patients. It is not very often that we stress on when the BP medications had to be taken to be most effective. The focus is on lowering the BP to expected goals hopefully through out the day and night. One of my previous posts was about an article that focused on a circadian clock and rhythm in the kidneys causing diurnal variations in the BP. Given the evidence that early stages of hypertension, there is a loss of the nocturnal dip, the 10-20% drop in the BP at night time, and it’s association with increased cardiovascular risk, it only makes sense to restore this nocturnal dip in order to decrease the risk. Recently saw this article. neat study, although it is open labeled with relatively small sample size, it is a prospective randomized open-label blinded end-point study, larger sample size than in any other trial to study this effect.
It is a general consensus that bringing the blood pressure to normal is more important than how it is done, in terms of what specific medications are used. But now it seems that it is not only important what medications we choose but also when we choose to give them
n = 661 332 awake group & 329 night time group (at least one medication at night time)
48h ambulatory BP monitoring
Follow up 5.4 years
Primary endpoint: adjusted risk for CV events was three times higher in the awake -group. Adjusted hazard ratio 0.31 p < 0.001
secondary endpoint: adjusted risk for composite outcome (MI, CV death, CVA) was three times higher in awake-group Hazard ratio 0.28 p <0.001
The night-time group had
lower asleep systolic BP mean p < 0.003
lesser proportion of patients with non dipping pattern 41% vs 71% p <0.001
higher proportion with controled BP 56 vs 45% p<0.003
awake BP similar in both groups p= 0.41
The difference in the cardiovascular risk was mainly due to restoration of the nocturnal dipping pattern. There was also a decrease in the albuminuria in the night time medication group.