The interplay between the continuity or quality of sleep and diurnal variation in blood pressure has not been directly examined before. We examined the influence of a mild, non-hypotensive sedative on nocturnal dipping.
This was a randomized, single-blind study.
The study took place in an out-patient clinic in an academic hospital.
Zolpidem 10 mg or placebo was given randomly for the first or second night, and ambulatory blood pressure monitoring was instigated for 48 h.
The populuation under study comprised 96 male patients with type 2 diabetes mellitus and hypertension (mean age 54±6 years, mean blood pressure 158/94±9/6 mmHg).
Main outcome measure
Nocturnal dipping (nocturnal blood pressure ≥10% lower than daytime pressure) was found in 71% of the patients taking the sedative compared with 27% of those on placebo (P=0.001).
On placebo, non-dippers and dippers had similar profiles of cardiovascular risk parameters. In contrast, non-dippers taking zolpidem had significantly higher values for most cardiovascular risk parameters compared with dippers: higher systolic blood pressure, higher low-density lipoproteins, lower high-density lipoproteins, higher serum creatinine, a higher urinary albumin : creatinine ratio, higher serum insulin and insulin resistance.
The use of a mild sedative during ambulatory blood pressure monitoring may help to identify the patients with a very high cardiovascular risk. These are the patients with a blunted nocturnal hypotension despite sedation.