Disease entity impacts muscle wasting in the ICU with COVID-19 patients losing muscle nearly twice as fast

Introduction

Muscle loss in critically ill patients, particularly during prolonged hospitalization, poses significant challenges to their recovery and long-term outcomes. Intensive care unit (ICU)-acquired weakness (ICUAW), a common complication in such patients, manifests as severe depletion of muscle mass and function^{1, 2–3}. The onset of muscle wasting typically occurs shortly after admission to the ICU and worsens progressively over time^4,5. The degree of muscle loss correlates with the severity of the underlying illness and the duration of hospitalization, with notably pronounced effects observed in patients diagnosed with sepsis⁶.

While several studies have documented muscle loss in the initial days following ICU admission, as highlighted in a recent meta-analysis encompassing 3251 critically ill patients⁷, comprehensive understanding of long-term muscle decay remains limited, with only a few studies addressing this aspect, typically involving small and heterogeneous cohorts^{8, 9, 10, 11–12}.

To address these gaps, we have previously used artificial intelligence (AI)-based muscle monitoring by segmenting clinically indicated computed tomography (CT) scans to analyze muscle wasting in two homogeneous cohorts. The first cohort included patients with severe SARS-CoV-2 infection, characterized by high mortality and significant muscle wasting¹¹. Similarly, the second cohort included patients with severe pancreatitis, a condition known to be associated with significant mortality, prolonged ICU stays and profound physiological deterioration^{13, 14–15}. By integrating muscle wasting data from both cohorts, this study aimed to provide a comprehensive perspective on long-term muscle wasting trajectories. In addition, we sought to identify the key factors influencing the dynamics of muscle wasting in these distinct patient populations.

Materials and methods

Ethics approval

The study received approval from the Institutional Review Board (Internal registration number: EA4/152/20) and adhered to the principles outlined in the Declaration of Helsinki. Due to the retrospective nature of the study, the Institutional Review Board of Charité waived the need of obtaining informed consent.

Study design and patient population

In this study, we conducted a retrospective analysis of changes in psoas muscle area (PMA) among patients admitted to the ICU due to either SARS-Cov-2 virus infection or AP. For patient selection, we screened our institutional database for individuals admitted with acute pancreatitis (AP) between January 2012 and December 2022, and with SARS-CoV-2 infection between...