BALTIMORE—Johns Hopkins researchers have discovered that a drop in blood potassium levels caused by diuretics commonly prescribed for high blood pressure could be the reason why people on those drugs are at risk for developing type 2 diabetes.
The drugs accelerate loss of fluids, but also deplete important chemicals, including potassium; therefore, those who take them generally are advised to eat bananas and other potassium-rich foods to counteract the effect.
“Previous studies have told us that when patients take diuretic thiazides, potassium levels drop and the risk of diabetes climbs to 50 percent,” said lead researcher Tariq Shafi, MD, MHS, of the Department of Nephrology at Johns Hopkins University School of Medicine. “For the first time, we think we have concrete information connecting the dots.”
Researchers examined data from 3,790 non-diabetic participants in the Systolic Hypertension in Elderly Program (SHEP). Half of the subjects were treated with chlorthalidone and half with a placebo. Of the 3,790 subjects, 1,603 were men and 724 were non-white and none had a history of diabetes.
The results, published online in the journal Hypertension, showed that for each 0.5 milliequivalent-per-liter (MEq/L) decrease in serum potassium, there was a 45-percent increased risk of diabetes. None of the people in the group receiving the placebo developed low potassium levels.
