Blog | Tuesday, November 11, 2008

Heart failure and exercise

It's heart failure day at AHA Scientific Sessions-- at least in terms of the late-breaking trials.

During a press conference about some of these trials, several physicians bemoaned the fact that the general public knows little about the common problem of heart failure. Milton Packer, MD, of the Univ. of Texas Southwestern Medical Center, quipped "We've been trying to find spokespeople for heart failure, but they are too short of breath to speak!" (Maybe that was funnier in person.)

One study looked at whether structured exercise training for HF patients reduced hospitalization or death rates. The results weren't statistically significant in the main analysis, but an adjusted analysis showed an 11% reduction in deaths/hospitalization, and a 15% reduction for CV mortality or HF hospitalization (a secondary endpoint).

The regimen in the study involved 36 supervised sessions of 30 mins of exercise 3x/week. At the 18th session, patients began to transition into exercising at home for 40 mins 5x/week by giving them a treadmill or exercise bike (wonder if they got to keep them once the study ended?) All patients were receiving optimal medication therapy.

There was some debate about how seriously to take the results, given that they were only significant after adjustment. The author, Dr. Christopher O'Connor of Duke, argued that since the adjustments were pre-specified, the analysis was "fair". He and several others also discussed how much more difficult it is to measure the effects of lifestyle interventions than, say, a drug-- suggesting one should cut this kind of study a little slack.

Dr. O'Connor also noted that the hazard ratios weren't much different in the two primary analyses: HR of 0.93 for main and 0.89 for adjusted. (The variables in the adjusted analysis, by the way, were CPX exercise duration, LVEF, Beck Depression Inventory and history of HF.)

It's also important to note there were no more adverse events-- like heart attack, angina or arrhythmia-- in the HF patients who exercised vs. those who got usual care. Both doctors and patients are often wary of prescribing exercise for HF patients, for fear of bad consequences, O'Connor said, so this provides some reassurance.