Prognostic value of nocturnal blood pressure and reverse-dipping status on the occurrence of cardiovascular events in hypertensive diabetic patients

Diabetes Metab. 2008 Dec;34(6 Pt 1):560-7. doi: 10.1016/j.diabet.2008.05.005. Epub 2008 Oct 15.

Abstract

Aim: To assess whether reverse-dipping status is associated with cardiovascular (CV) events such as CV death, myocardial infarction (MI) or stroke in diabetic patients with hypertension.

Methods: A total of 97 diabetic patients underwent their first ambulatory blood pressure monitoring (ABPM 1). "Reverse dippers" were defined as patients with a nighttime systolic and/or diastolic blood pressure (BP) greater than daytime systolic and/or diastolic BP. Other patients were called "others". A second ABPM (ABPM 2) was done after a median delay of 2.6 years. Patients were then followed for a further 2.9-year median period (total median follow-up: 5.5 years).

Results: After ABPM 1, CV events occurred in 53% of the reverse dippers (n=15) and in 29% of the others (n=82). Kaplan-Meier curves showed significant differences between the two groups (P=0.003). Mean nighttime systolic BP on ABPM 1 was 148+/-23 mmHg and 142+/-19 mmHg in patients who did and did not experience a CV event, respectively. With Cox analysis adjusted for confounders, a 10 mmHg increase in nighttime systolic BP was associated with a 35% increase in the risk of a CV event (hazard ratio [HR]: 1.35, P=0.003). The HR for a CV event in reverse- versus nonreverse-dipping status was 2.79 (P=0.023). After ABPM 2, the relationship between the reverse-dipping status and occurrence of CV events was no longer evident (P=0.678). Nighttime systolic BP remained predictive of CV events (P=0.001).

Conclusion: These findings suggest that nighttime systolic BP per se appeared to be a stronger predictor of an excess risk of CV events compared with reverse-dipping status.

MeSH terms

  • Aged
  • Blood Pressure / physiology*
  • Blood Pressure Determination
  • Cardiovascular Diseases / epidemiology
  • Circadian Rhythm / physiology*
  • Creatinine / blood
  • Diabetes Complications / blood
  • Diabetes Complications / physiopathology*
  • Diabetic Angiopathies / epidemiology
  • Diabetic Nephropathies / epidemiology
  • Diabetic Nephropathies / physiopathology
  • Diastole / physiology
  • Female
  • Glycated Hemoglobin A / metabolism
  • Humans
  • Hypertension / blood
  • Hypertension / physiopathology*
  • Male
  • Middle Aged
  • Pilot Projects
  • Predictive Value of Tests
  • Prognosis
  • Sleep Apnea Syndromes / physiopathology
  • Systole / physiology

Substances

  • Glycated Hemoglobin A
  • Creatinine