Predictors of New-Onset Diabetes Identified in Patients With Hypertension

The major predictors of new-onset diabetes (NOD) in patients with hypertension were baseline fasting plasma glucose (FPG) level greater than 90mg/dL. (5mmol/L), body mass index (BMI), and use of an atenolol regimen with or without a diuretic, according to the results of the Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm (ASCOT-BPLA).

"Observational data suggest that hypertension is a risk factor for type 2 diabetes and hence the two conditions frequently coexist," write Ajay K. Gupta, MD, from the International Centre for Circulatory Health, National Heart & Lung Institute in Imperial College, London. "The increased propensity of the hypertensive population to develop diabetes is variably affected by different classes of antihypertensive medication."

The goal of this study was to determine the baseline predictors of NOD in patients with hypertension and to develop a risk score to detect those at high risk for NOD.

ASCOT-BPLA was a randomized trial comparing 2 antihypertensive regimens: atenolol ± thiazide or amlodipine ± perindopril. Of 19,257 patients in the ASCOT-BPLA who were randomized to receive 1 of these regimens, 14,120 were "at risk" of developing diabetes at baseline, and 1366 (9.7%) subsequently developed NOD during follow-up (median duration, 5.5 years). Independent predictors of NOD were developed with a multivariate Cox model, and these predictors were used to calculate individual risk scores.

Significant predictors of the development of NOD were increased baseline FPG levels, BMI, serum triglyceride levels, and systolic blood pressure (SBP). Protective factors were an amlodipine ± perindopril regimen (vs atenolol ± thiazide; hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.59 – 0.74) as well as increased high-density lipoprotein (HDL) cholesterol levels, alcohol use, and age older than 55 years.

The most powerful predictor of NOD was FPG levels, with the risk increasing by 5.8 times (95% CI, 5.23 – 6.43) for each 18mg/dL. (1 millimole-per-liter rise above 5 mmol/L). With increasing quartile of risk score, the risk for NOD increased steadily. Compared with those in the lowest quartile, those in the highest quartile had a 19-fold increase (95% CI, 14.3 – 25.4) in the risk for NOD.

The multivariate risk model had excellent internal validity as well as discriminative ability, and the risk score developed from that model allowed accurate prediction of NOD in a 5-year period for an individual.

"Baseline FPG >90mg/dL.(5mmol/l), BMI and use of an atenolol ± diuretic regimen were among the major determinants of NOD in hypertensive patients," the study authors write. "The model developed from these data allows accurate prediction of NOD among hypertensive subjects."

"Pending further definitive evidence related to cardiovascular morbidity and mortality with antihypertensive-associated incident diabetes, it seems at best unwise, except where compelling indications apply, to use beta-blockers and diuretics in combination in preference to other combinations such as CCB [calcium-channel blocker] plus an ACE [angiotensin-converting enzyme] inhibitor, particularly since the latter agents have been shown to be more cost-effective," the study authors conclude.
Practice Pearls:

• In the ASCOT-BPLA, factors significantly associated with development of NOD in patients with hypertension were increased baseline FPG levels, BMI, serum triglyceride levels, and SBP. Protective factors were an amlodipine ± perindopril regimen (vs atenolol ± thiazide), increased HDL cholesterol levels, alcohol use, and age older than 55 years. The most powerful predictor of NOD was FPG level.
• With increasing quartile of risk score developed from these predictive factors, the risk for NOD steadily increased. Compared with those in the lowest quartile of risk score, those in the highest quartile had a 19-fold increase in the risk for NOD. The multivariate risk model had excellent internal validity as well as discriminative ability, and the risk score allowed accurate prediction of NOD for an individual for a 5-year period.

Diabetes Care. Published online February 11, 2008.

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FACT:
Cutting Kids’ Salt Intake May Rein in Obesity: Children with lower levels of salt intake drink fewer sugar-sweetened soft drinks and are probably at lower risk of obesity, hypertension, myocardial infarction, and stroke, according to WebMD. Investigators from St. George’s University of London, United Kingdom, analyzed 7-day salt and fluid intake data from the 1997 British National Diet and Nutrition Survey on more than 1600 children from the ages of 4 to 18. The authors estimated that for every 1 g of salt cut from the daily diet, the children reduced fluid intake by 100 g per day. Children who ate a lower-salt diet also drank fewer sugar-sweetened soft drinks, resulting in an estimated reduction of 27 g of sugar per day for every 1 g salt removed from the diet.

 Circulation, published onlineFebruary 20, 2008