Date Published: April 15, 2019
Publisher: Public Library of Science
Author(s): Jessamine Y. J. Liu, Esmee M. Reijnierse, Jeanine M. van Ancum, Sjors Verlaan, Carel G. M. Meskers, Andrea B. Maier, Pasquale Abete.
Hospitalisation is associated with adverse health outcomes including loss of muscle strength, muscle mass and functional decline, which might be further aggravated by acute inflammation. This study aimed to determine whether acute inflammation, as denoted by C-reactive protein (CRP), is associated with muscle strength, muscle mass and functional dependency in hospitalised older patients.
The observational, prospective EMPOWER study included 378 hospitalised patients aged 70 years and older. As part of the hospital assessment, 191 patients (50.5%) had CRP measured. Muscle strength and mass were measured using handheld dynamometry and bioelectrical impedance analysis respectively. Activities of Daily Living (ADL) were assessed using Katz score and Instrumental ADL (IADL) by Lawton and Brody score. Linear regression analyses and logistic regression analyses were performed stratified by sex and adjusted for age and comorbidities.
Mean age was 79.7 years (SD 6.4) and 50.8% were males. On admission and discharge, males with elevated CRP had significantly lower handgrip strength and lower absolute muscle mass compared with males with normal CRP and those with no CRP measured. At three months post-discharge, males with elevated CRP were more likely to be ADL dependent than those with normal CRP and with no CRP measured. In females, no associations were found between CRP and muscle strength, muscle mass, ADL or IADL.
Hospitalised older male patients with acute inflammation had lower muscle strength at admission and discharge and lower absolute muscle mass at admission and higher ADL dependency at three months post-discharge.
Hospital admissions of older adults have more than doubled in the last decade . Hospitalisation is associated with adverse outcomes such as delirium, falls, loss of muscle strength and muscle mass, and reduced functional ability to perform activities of daily living (ADL) [2–6]. Older patients have less physiological reserve compared to younger individuals, so even a small reduction in muscle strength and functional ability may have a significant influence on their functional independence and living situations [7,8].
Fig 1 shows the flowchart of patient screening, inclusion, follow-up, and patients included for the present analyses. Table 1 shows the baseline characteristics of patients stratified by sex. The mean age was 79.7 years (SD 6.4) and 49.2% were females. The majority of patients were living independently prior to hospitalisation (94.4%) and were acutely admitted (84.7%). The median length of stay was 5 days (IQR 3–8 days). Of the 191 patients with measured CRP, 155 had elevated CRP (81%) and 36 (19%) had normal CRP.
In male hospitalised patients 70 years and older, acute inflammation was associated with lower muscle strength and lower absolute muscle mass on admission, and with significantly lower muscle strength at discharge, independent of the severity of inflammation. Acute inflammation was associated with higher ADL dependency on admission and at three months after discharge in males. In females, acute inflammation was only associated with lower muscle strength on discharge and increase in IADL independence score at three months post-discharge.
Hospitalised older male patients with acute inflammation had significantly lower muscle strength on admission and discharge, significantly lower absolute muscle mass on admission, and significantly increased activities of daily living dependency at three months post-discharge. In females, acute inflammation was associated with lower muscle strength on discharge. This has implications for targeted rehabilitation follow up in patients with acute inflammation, to optimise their muscle strength, muscle mass and restore the premorbid level of function. Longitudinal studies would be required to assess the trajectory of muscle strength and muscle mass following acute inflammation in the short and medium term following discharge.