Short-term reproducibility of a non-dipping pattern in type 2 diabetic hypertensive patients.
BACKGROUND
Little information is available on the reproducibility of nocturnal variations in blood pressure in type 2 diabetic hypertensive patients.


OBJECTIVE
We aimed to compare the intrasubject short-term reproducibility of a nocturnal non-dipping pattern and the prevalence of cardiac and extracardiac signs of target organ damage, in a group of type 2 diabetic hypertensive patients and in an age/gender-matched group of non-diabetic hypertensive subjects.


METHODS
Thirty-six treated hypertensive patients with long-lasting type 2 diabetes (> 10 years duration) consecutively attending our hospital out-patient hypertension clinic (group I; mean age, 65 +/- 9 years), and 61 untreated non-diabetic subjects with grade 1 and grade 2 uncomplicated essential hypertension, matched for age and gender, and chosen from patients attending an outpatient clinic (group II; mean age, 65 +/- 5 years), were considered for this analysis. All patients underwent blood sampling for routine blood chemistry, 24-h urine collection for microalbuminuria, two 24-h periods of ambulatory blood pressure monitoring (ABPM) within a 4-week period, echocardiography, and carotid ultrasonography. A dipping pattern was defined as a greater than 10% reduction in the average systolic and diastolic blood pressure at night compared with average daytime values.


RESULTS
A reproducible nocturnal dipping and non-dipping profile was found in 11 (30.6%) and 21 (58.3%) diabetic patients, respectively; while only in four (11.1%) patients was a variable dipping profile observed. Of the 23 patients with a non-dipping pattern during the first ABPM period, 21 (91.3%) also had this type of pattern during the second ABPM recording. In group II (non-diabetic hypertensive patients), 30 patients (49.2%, P < 0.05) had a dipping pattern, 13 patients (21.3%, P < 0.01) had a non-dipping profile pattern and 18 patients (29.5%, P < 0.01) had a variable dipping pattern. Of the 20 patients with a non-dipping pattern during the first ABPM period, 13 (65.0%) confirmed this type of pattern during the second ABPM recording. Finally, the prevalence of left ventricular hypertrophy (77.7 versus 41.4%, P < 0.01), carotid plaques (80.5 versus 38.3%, P < 0.01), carotid intima-media thickening (54.3 versus 44.0%, P < 0.05) and microalbuminuria (11.1 versus 2.0%, P < 0.01) was significantly higher in group I than in group II. According to a logistic regression analysis, diabetes, left ventricular hypertrophy and carotid plaques were the main independent predictors of the non-dipping (pattern in the overall population.


CONCLUSIONS
These findings indicate that intrasubject variability of non-dipper pattern is lower in diabetic than in non-diabetic hypertensive patients, that classification of diabetic hypertensive patients as dipper or non-dipper on the basis of a single ABP recording is more reliable than in non-diabetic patients, and that the more frequent and reproducible non-dipping (pattern in diabetic patients is associated with a more prominent cardiac and extracardiac target organ damage.
Istituto di Medicina Cardiovascolare and Centro Interuniversitario di Fisiologia Clinica e Ipertensione, Università di Milano, Ospedale Maggiore IRCCS, Milan. dhipertensione@libero.it
Cesare
C
Cuspidi
Stefano
S
Meani
Laura
L
Lonati
Veronica
V
Fusi
Cristiana
C
Valerio
Carla
C
Sala
Gaia
G
Magnaghi
Meilikemu
M
Maisaidi
Alberto
A
Zanchetti
D000368:Aged; D000419:Albuminuria / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002940:Circadian Rhythm; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D004452:Echocardiography; D005260:Female; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013997:Time Factors