Use of a mild sedative helps to identify true non-dippers by ABPM: a study in patients with diabetes mellitus and hypertension

BACKGROUND: 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. DESIGN: This was a randomized, single-blind study. SETTING: The study took place in an out-patient clinic in an academic hospital. INTERVENTION: Zolpidem 10 mg or placebo was given randomly for the first or second night, and ambulatory blood pressure monitoring was instigated for 48 h. PATIENTS: The population 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). RESULTS: 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. CONCLUSION: 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.