Impact of diaphragm atrophy in elderly patients with heart failure: a multicenter prospective cohort study

Abstract

Abstract Background The diaphragm plays an important role in cardiac and respiratory functions. However, the importance of diaphragm atrophy in patients with heart failure (HF) has not been well described. Purpose To assess the feasibility of ultrasound-based assessment of the diaphragm and its prognostic impact in elderly patients with HF. Methods We conducted a multicenter prospective cohort study enrolling patients hospitalized with HF aged ≥65 years. Diaphragm thickness at rest and during inspiration was measured with ultrasound before discharge by certified observers, and interobserver variability was assessed using 90 images. Results Of the 599 enrolled patients (median 81 [74 - 86] years old, 55% female), mean diaphragm thickness at rest and during inspiration were 1. 9 ± 0.6 and 3.1 ± 1.2 mm, respectively. Interobserver variability was small with an intraclass correlation coefficient of 0.84 (0.76 – 0.89). Patients with thin (< 1.9 mm) diaphragm at rest (n = 304) had smaller body mass index (20.9 ± 3.6 vs 22.2 ± 4.0 kg/m2, p < 0.001), higher NYHA class (class II or higher 78% vs 61%, p < 0.001), lower % forced expiratory volume in 1 second (83.2 ± 22.3% vs 88.7 ± 23.7%, p = 0.013), and lower handgrip strength (18.1 ± 7.3 vs 19.8 ± 8.0 kg, p = 0.009). During the median follow-up of 663 [456 - 882] days, 160 patients died. Kaplan-Meier curve analysis showed significant stratification by quartile groups of diaphragm thickness at rest. After adjustment for the established MAGGIC risk score, diaphragm thickness was significantly associated with all-cause death (hazard ratio 0.56 [0.41 – 0.71] /mm, p < 0.001). Conclusions Diaphragm atrophy was prevalent in elderly patients with HF and had a strong association with all-cause death. Further studies are necessary to evaluate the efficacy of interventions.