A Prospective Observational Study Evaluating Sarcopenia By Using the Bioelectrical Impedance Analysis in Elderly Patients with Hematologic Malignancies

[Introduction] Sarcopenia is characterized by age-related decline of skeletal muscle plus low muscle strength and/or physical performance. Previous studies have confirmed the association of sarcopenia and adverse health outcomes, such as falls, disability, hospital admission, long term care placement, poorer quality of life, and mortality, which denotes the importance of sarcopenia in the health care for older people. Population-based studies reported that the prevalence of sarcopenia in Japanese healthy adults aged≥60 years was 8.5% among men and 8.0% among women. Sarcopenia was recently identified as a poor prognostic factor in patients with solid tumors. In cancer patients, sarcopenia is associated with treatment failure, chemotherapy toxicity, and a shorter time to tumor progression related to survival. In contrast to solid tumors, the clinical relevance of sarcopenia in hematologic malignancies is still unknown. The present study investigated the prevalence of sarcopenia based on the criteria of the Asian Working Group for Sarcopenia (AWGS) in elderly patients with hematologic malignancies.

[Patients and Methods] We prospectively analyzed 56 elderly patients aged≥60 years with hematologic malignancies diagnosed at our institution between 2015 and 2018. Appendicular skeletal muscle mass (ASM) was measured at diagnosis by using multifrequency bioelectrical impedance analysis (BIA) (InBody 720). BIA is suitable for body composition monitoring in elderly patients as a fast, noninvasive, and convenient method. Skeletal muscle index (SMI) was defined as the ratio of ASM divided by height in square centimeters. We also evaluated physical function by using short physical performance buttery (SPPB). Sarcopenia was defined according to the AWGS algorithm, in which the patient has low muscle mass, and low muscle strength or low physical performance. Low muscle mass was defined as a skeletal muscle index (SMI: ASM/height²) of <7.0kg/m² in men and <5.7kg/m² in women. Pre-sarcopenia was defined as having only low muscle mass. Low muscle strength was defined as a handgrip strength of <26kg in men and <18kg in women; and low physical performance, as a gait speed of <0.8m/sec. The study protocol was approved by the Institutional Review Board of Yokohama Municipal Citizen's Hospital, and it was carried out in accordance with the Declaration of Helsinki.

[Results] Median age at diagnosis was 77 years (60-93 years), with 34 males and 22 females. The diagnosis included non-Hodgkin lymphoma (NHL, n=36), multiple myeloma (MM, n=9), myelodysplastic syndrome (MDS, n=10), and acute myeloid leukemia (AML, n=1). The prevalence of low muscle mass (pre-sarcopenia) was 41% (14/34) in men and 77% (17/22) in women. The prevalence of low muscle strength was 35% (12/34) in men and 41% (9/22) in women. The prevalence of low physical performance status (Gait speed:<0.8m/sec) was 6% (2/34) in men and 9% (2/22) in women. The prevalence of sarcopenia based on a diagnosis of low muscle mass, low muscle strength, and low physical performance was 24% (8/34) in men and (8/22) 36% in women. The prevalence of low SPPB score (<10) was 9% (3/34) in men and 18% (4/22) in women. Among 36 NHL patients, the diagnosis included DLBCL (n=15), FL (n=10), MALT (n=3), SMZBCL (n=3), MCL (n=2), and others. The prevalence of sarcopenia was 25% (5/20) in men and 50% (8/16) in women. The mean age was 83 years in the sarcopenic group (n=13, 36%) and 73 years in the non-sarcopenic group (n=23, 64%) (p=0.0001). Sarcopenic patients displayed a similar level of serum albumin, LDH, sIL2-R, and BMI when compared with patients who were not sarcopenic. However, sarcopenic patients displayed significantly lower levels of serum dehydroepiandrosterone-sulfate (DHEA-S) and a higher CCI score than patients who were not sarcopenic. Sarcopenic patients failed to complete the treatment planned as compared with non-sarcopenic patients (p=0.001).

[Conclusion] These results demonstrated that the prevalence of sarcopenia in elderly patients with hematologic malignancies is higher than that in the Japanese general elderly population. In particular, the prevalence of sarcopenia in female NHL patients is higher than that in male NHL patients. Several factors such as age, serum DHEA-S or comorbidities may affect the incidence of sarcopenia. Since our results are based on a small-sized analysis, further large prospective studies are warranted to verify this conclusion.