Hypertension Predominant Cause of HF in Africa; Affects the Middle-Aged

October 09, 2012

October 8, 2012 (Maputo, Mozambique) — Heart failure is predominantly caused by hypertension in sub-Saharan Africa, and it affects patients there almost 20 years earlier than it does those in industrialized nations, new data from a contemporary registry indicate [1]. Dr Albertino Damasceno (Eduardo Mondlane University, Maputo, Mozambique) and colleagues report their findings from the Sub-Saharan Africa Survey of Heart Failure (THESUS-HF) in the October 8, 2012 issue of the Archives of Internal Medicine.

Senior author Dr Karen Sliwa (University of Cape Town, South Africa) told heartwire the results show that "heart failure is common in Africa and affects men and women equally," which differs from the presentation in Western countries, where men predominate. High blood pressure is the cause in around 45% of cases, "and the outcome is particularly poor," given the relative youth of the patients, with 17.8% of patients dying within six months, she says. In addition, treatment is far from optimal.

These high mortality rates indicate a pattern of disease that "has striking parallels with US black patients of African descent," say Drs Kenneth A Jamerson (University of Michigan Health System, Ann Arbor) and Lawrence Agodoa (National Institutes of Health, Bethesda, Maryland) in an accompanying editorial [2].

We appreciate the careful work of the THESUS-HF investigators as they carefully phenotype the etiology of heart failure in their region of the world.

"We appreciate the careful work of the THESUS-HF investigators as they carefully phenotype the etiology of heart failure in their region of the world," Jamerson and Agodoa add. "The data . . . place the treatment of hypertension in a central role for the global improvement of cardiovascular health."

HF in Africa Affects Breadwinners and Caregivers in the Prime of Life

The THESUS-HF registry was a prospective, multicenter, observational survey of 1006 patients with acute HF admitted to 12 university hospitals in nine countries from July 1, 2007 to June 30, 2010. Enrollment ranged from 430 patients in Nigeria to just 10 in Ethiopia. Other contributors included Uganda, South Africa, Cameroon, Mozambique, Sudan, Kenya, and Senegal. The causes, treatment, and outcomes of acute heart failure were determined during six months of follow-up.

Preliminary findings from THESUS-HF were presented at the AHA meeting last year, but the new paper "is a more detailed analysis and now contains all of the outcomes data," Sliwa explained. Representing Africa's first and largest multinational prospective registry of acute HF, the survey reveals a few unique characteristics of the disease there, she notes.

Key among these is the young ages of sufferers--those affected by HF in sub-Saharan Africa were 55 years old, on average, compared with 72 in Western nations. This illustrates how the disease is afflicting breadwinners and caregivers in the prime of life, notes Sliwa.

And although hypertension was the predominant cause (45.4%), the results illustrate the "double burden" of infectious and noninfectious diseases in Africa, she says. Rheumatic heart disease accounted for 15% of cases; pericarditis--mainly caused by tuberculosis--was responsible for 5%; and HIV-associated cardiomyopathies caused 2.4% of heart failure there. And 65 of 500 patients undergoing testing (13.0%) were HIV positive.

Other findings include the fact that HF was rarely of ischemic origin in Africa (only 7.7% of cases), in contrast to the West, although the investigators point out this figure may have been an underestimate because there was no access to cardiac catheterization in a number of centers.

Plan for Trial of Medications Thought to Work Best in Black Patients

There are also some important observations about medical therapy from the study, says Sliwa. Use of aspirin was high, despite the fact that ischemic HF was uncommon, and use of beta blockers was low, with only about half of the patients receiving them.

Finally, the combination of hydralazine hydrochloride and nitrates, which has been shown to be effective in patients of African descent, "is hardly ever used in the sub-Saharan region," the researchers observe.

Sliwa says a trial of hydralazine and nitrates to improve outcomes among African patients is now enrolling, using the same centers that participated in THESUS-HF. "While it was important to get the data, we were performing the additional function of capacity building for future research," she observed.

In this study, called B-E-HAF, around 500 patients will be optimized on beta blockers, ACE inhibitors, and spironolactone therapy and then half will be randomized to hydralazine plus nitrates, while the remainder will receive placebo. Results are expected in around two years.

The authors and editorialists report no conflicts of interest.

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