News in medicine

By Ryan Laverty

A University of Calgary cardiac researcher recently completed a study indicating a commonly prescribed heart failure medication may not benefit African American patients as much as it does Caucasians.

With help from colleagues across North America, Dr. Derek Exner pooled and analyzed data from two groups of subjects in trials from earlier heart medication studies, entitled Studies of Left Ventricular Dysfunction. The subject groups were observed to compare the effectiveness of the commonly used angiotensin converting enzyme inhibitor, enlapril. Enlapril combats heart failure by preventing blood vessel constriction.

"We were continuing with research that suggested there are differences in the responses to medication for heart failure dependent on ethnicity," explained Dr. Exner. "Some people do better with one type of treatment than others."

The patients grouped themselves as "black" or "white" and were further divided by such factors as socioeconomic status to compare their responses. Subjects took either the ACE inhibitor, enlapril, or a placebo and patients were monitored over several years beginning in 1997.

The study results indicated that "white" patients taking enlapril were 40 per cent less likely to be admitted to hospital for heart failure than were those taking the placebo or "black" patients taking
either enlapril or the placebo.

"What we found does not mean that all African Americans are genetically less receptive to the medication," said Exner. "It probably has as much to do with diet as it does genetics."

Exner explained that many of the African American patients in the study were from the southern United States, thus high-sodium diets may have contributed to higher blood pressures and a greater probability of heart failure.

"The conclusions we’ve drawn from this work do not mean that ACE inhibitors don’t work for African Americans," said Exner. "It may mean that more attention needs to be paid to blood pressure levels. It might also mean either changing dosage, or changing to a different ACE inhibitor."

Dr. Exner and colleagues are continuing research to determine what might increase prevention efficiency in African American patients.

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