Abstract Background In elderly people, a decline in activities of daily living is more closely associated with low muscle strength (dynapenia) than with low muscle mass. Moreover, the combination of low muscle strength and obesity (dynapenic obesity) is associated with a higher risk of mortality than dynapenia or obesity alone, but its influence on prognosis is still unknown in elderly heart failure (HF) patients. To clarify these relationships may contribute to the development of rehabilitation programs for elderly HF patients and the improvement their prognoses in the future. Purpose We aimed to investigate the influence of dynapenia and obesity on prognoses of elderly HF patients. Methods We evaluated 1006 elderly HF patients aged ≥65 years (76.5±6.9 years, 579 males) who were admitted to our hospital and participated in an inpatient cardiac rehabilitation program. We assessed patients' characteristics, including body mass index (BMI) and handgrip strength during hospitalization. Patients with low handgrip strength (<26 kg and <18 kg in males and females, respectively) and high BMI (≥25 kg/m2) were considered to have dynapenia and obesity, respectively. Moreover, patients fulfilling the above two criteria (dynapenia, obesity) were considered to have dynapenic obesity. Patients were divided into four groups: normal, dynapenia only, obesity only, and dynapenic obesity. We compared survival rates among the four groups using the Kaplan-Meier method and log-rank test. To identify predictors for all-cause mortality, we performed Cox regression analysis. Results During the 8-year follow-up period, 228 patients (21.2%) died. Eight-year cumulative incidences of mortality were 35.4%, 26.0%, 62.6%, and 33.1% in the normal, obesity only, dynapenia only, and dynapenic obesity groups, respectively. Significantly lower survival rates were observed in the dynapenia only group than in the other 3 groups (log-rank: 28.893, P<0.001). Cox regression analysis, after adjusting for age and sex, showed significantly poor prognosis in the dyanapenia only group than in the other 3 groups (normal group, hazard ratio [HR] = 0.684, 95% confidence interval [CI] = 0.488–0.959, P=0.028; obesity only group, HR = 0.330, 95% CI = 0.182–0.598, P<0.001; dynapenic obesity group, HR = 0.390, 95% CI = 0.206–0.739, P=0.004). Conclusion Elderly HF patients with dynapenia alone had poor prognoses. Obesity may have protective effects on the survival of dynapenia patients with HF.
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