"One has to worry that the problems with worsening renal function and hyperkalemia may be much more common in clinical practice than in the highly monitored environment of a clinical trial," added Dr. Redfield, professor of medicine at the Mayo Clinic, Rochester, Minn.
Dr. Margaret Redfield
Other heart failure experts not involved in TOPCAT took a more positive view of the study.
Dr. Clyde W. Yancy, AHA spokesperson, said in an interview that HFpEF is probably even more common than systolic heart failure, and it is a disease for which physicians have had no proven-effective treatments.
"You can almost justifiably say, ‘Let’s just look at the Americas, where patients had event rates that are consistent with the disease we think we understand.’ And it looks like there’s a signal there. I think that there’s enough evidence in TOPCAT for the clinical pragmatist to be able to be comfortable that spironolactone is probably beneficial and can be given safely. If you are convinced you can give it safely in your own clinical scenario, I think you should use it," said Dr. Yancy, professor of medicine and chief of cardiology at Northwestern University, Chicago.
Dr. Marco Metra, a cardiologist at the University of Brescia (Italy), said he interprets the TOPCAT results as an indication for prescribing spironolactone, at least in HFpEF patients with high natriuretic peptide levels or multiple heart failure hospitalizations.
Dr. Pitt, emeritus professor of cardiovascular medicine at the University of Michigan, Ann Arbor, emphasized that in prescribing spironolactone, whether for HFpEF or systolic heart failure, it’s obligatory to measure potassium and creatinine levels at baseline, when changing the dose, and at each routine follow-up visit, titrating in response to the results. Failure to do so is akin to prescribing warfarin for a patient with atrial fibrillation and then never measuring the INR (international normalized ratio) he said.
TOPCAT was sponsored by the National, Heart, Lung, and Blood Institute. Dr. Pfeffer and Dr. Pitt serve as consultants to numerous pharmaceutical companies that had no involvement in the trial.