Risk-factor clustering and cardiovascular disease risk in hypertensive patients

Am J Hypertens. 2007 Jun;20(6):599-607. doi: 10.1016/j.amjhyper.2006.10.013.


Background: Patients with hypertension often have other major risk factors for cardiovascular disease (CVD). Little is known, however, about the extent of risk-factor clustering in these patients and its importance in CVD risk and medical-care costs.

Methods: Study subjects were selected from the electronic medical records system of Kaiser Permanente Northwest, a large health maintenance organization, and included all patients aged > or =35 years with hypertension who were free of CVD in 1998. Subjects were stratified into eight risk-factor clusters based on whether or not they also had diabetes, hyperlipidemia, or a high body mass index (BMI). The risk of cardiovascular events was examined in each cluster over 6 years beginning January 1, 1999, using Kaplan-Meier methods and Cox proportional hazards models. Cumulative total medical-care costs (per patient) over 6 years also were examined.

Results: A total of 57,573 patients with hypertension who were free of CVD in 1998 were identified; 56% of subjects also had diabetes, hyperlipidemia, or high BMI. In analyses controlling for age, sex, and smoking status, the relative risk of cardiovascular events over 6 years was highest for patients with comorbid diabetes, ranging from 2.07 (95% confidence interval, 1.86-2.30) for those with diabetes only to 2.80 (95% confidence interval, 2.48-3.17) for those with diabetes, hyperlipidemia, and high BMI. Cumulative medical-care costs generally increased with additional risk factors. Comorbid diabetes had the greatest impact on costs over 6 years.

Conclusions: More than 50% of patients with hypertension also had diabetes, hyperlipidemia, or high BMI. Patients with these additional risk factors (especially diabetes) had a substantially higher CVD risk and medical-care costs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Aged
  • Cardiovascular Diseases / complications*
  • Cardiovascular Diseases / economics*
  • Cluster Analysis
  • Diabetes Complications / complications
  • Diabetes Complications / economics
  • Female
  • Health Care Costs / statistics & numerical data*
  • Humans
  • Hyperlipidemias / complications
  • Hyperlipidemias / economics
  • Hypertension / complications*
  • Hypertension / economics
  • Kaplan-Meier Estimate
  • Male
  • Metabolic Syndrome / complications
  • Metabolic Syndrome / economics
  • Middle Aged
  • Obesity / complications
  • Obesity / economics
  • Proportional Hazards Models
  • Risk Factors
  • Sex Factors
  • Smoking / adverse effects