Predictors of successful long-term blood pressure control in type 2 diabetic patients: data from the Swedish National Diabetes Register (NDR)

BACKGROUND: Hypertension in patients with diabetes is a well recognized cardiovascular risk factor for which the benefits of treatment are strongly evidence based. Less is known about predictors for successful long-term blood pressure control in these patients, including the potential role of body mass index (BMI), glycaemic control, microalbuminuria and smoking. MATERIAL AND METHODS: We used longitudinal data on risk factor levels from repeated clinical surveys of 1759 type 2 diabetic patients in the Swedish National Diabetes Register (NDR), a nationwide annual registration of quality indicators in diabetes care. Subjects with successful blood pressure (BP) control (systolic BP < 135 mmHg and diastolic BP < 85 mmHg) at baseline in 1997, in 2001, and at follow-up in 2003, were compared to subjects with BP control >or= 135/85 mmHg. RESULTS: Logistic regression analysis disclosed that successful BP control during the study period was predicted by lower BMI (P < 0.001), a lower frequency of microalbuminuria (P = 0.002), and lower age (P < 0.001) at baseline in 1997, and was still associated with lower BMI (P < 0.001), a lower frequency of microalbuminuria (P = 0.01) and lower age (P < 0.001) at follow-up. Successful BP control was also associated at follow-up with a lower frequency of the metabolic syndrome (30 versus 75%) and lower predicted 10-year risks [United Kingdom Prospective Diabetes Study (UKPDS) Risk Engine] of coronary heart disease (14 versus 29%) and stroke (10 versus 22%) (all P < 0.001). CONCLUSION: A lower BMI and absence of microalbuminuria were strong independent predictors of long-term successful BP control in type 2 diabetic patients, also characterized by a lower frequency of the metabolic syndrome and lower 10-year risk of cardiovascular disease. This implies the long-term benefits on BP control of lifestyle measures as well as control of microalbuminuria.