Body composition a good death predictor in MI patients after PCI

Among myocardial infarction (MI) patients who had undergone percutaneous coronary intervention (PCI), those with low fat-free mass (FFM) and body fat (BF) seem to suffer from excess mortality risk, a recent study has found. Body composition appears to be a better mortality predictor than body mass index.

Researchers assessed data from 6,543 MI patients (mean age 64.9 years, 30.8 percent women), who were then divided into two categories (high/low) according to FFM index (FFMI) and BF. Outcomes of interest were 30-day and long-term all-cause mortality.

During the study duration, a total of 1,938 participants died, yielding an overall mortality rate of 30.0 percent. Meanwhile, 504 patients died within 30 days, resulting in a 30-day all-cause mortality rate of 7.8 percent. At baseline, participants had a median BF of 24.3 kg and mean FFM of 55.4 kg. Survivors were more likely to be younger, male, have higher body mass index and FFMI, and have lower BF.

In the short-term, mortality was lowest in patients with high FFMI and low BF (3.0 percent), increasing progressively in the high FFMI-low BF (6.6 percent), low FFMI-low BF (10.4 percent), and low FFMI-high BF (14.7 percent) groups. Of note, the increasing trend was both significant and nearly linear (p<0.0001).

A similar pattern was reported for unadjusted long-term, all-cause mortality, increasing from the high FFMI-low BF (9.8 percent) group through the high FFMI-high BF (27.0 percent), low FFMI-low BF (36.0 percent), and low FFMI-high BF (56.8 percent) groups (p<0.0001).

Multivariable adjustment revealed that FFMI-BF groupings significantly and independently predicted 30-day (p=0.031) and long-term (p<0.0001) mortality risk. Body mass index, on the other hand, was only predictive of 30-day mortality (p=0.022), and not long-term death risk (p=0.12).