Association of Long COVID-Related inflammatory Processes in the Musculoskeletal System: 12-Month Longitudinal Cohort Feasibility Study

Background: A subset of individuals develops persistent symptoms following SARS-CoV-2 infection, including musculoskeletal (MSK) manifestations, a condition known as long COVID (LC). Emerging hypotheses suggest that chronic low-grade inflammation in LC may impair bone metabolism and compromise joint health. However, empirical evidence is limited, and the impact of LC on MSK health, particularly bone and joint integrity, is poorly understood. Aim: To determine the influence of LC on MSK function, including bone health, body composition, and joint integrity. Methods: A 12-month longitudinal prospective cohort feasibility study was conducted involving 45 adults with LC and 40 well-recovered (WR) post-COVID-19 controls. Baseline and follow-up assessments included dual-energy X-ray absorptiometry (DXA) for bone mineral density (BMD) and total body composition (TBC), alongside ultrasound of the hand and knee joints to evaluate intra-articular changes. Results: The LC group had more fat in the gynoid, android, and leg regions at each assessment point compared to the controls (p<0.01). LC showed a significantly lower synovial hypertrophy at the baseline, 13% compared to WR 45% (p=0.001), and a marginal improvement in hand synovial hypertrophy, over 12 months, from a median of 2 (IQR 1;5) to 1 (IQR 0;3) (p=0.012), as observed via MSK ultrasound. No notable differences were found between groups regarding BMD, either in the LC group compared to the control group or overtime. Conclusion: This cohort study of LC adults and controls found no evidence of rapid bone loss; however, adiposity and joint symptoms suggest the need for ongoing monitoring. Future research should focus on MSK markers, muscle function, advanced imaging, and improving MSK health.