Editorial Note: The 2026 International AIDS Conference (AIDS 2026) was held in Rio de Janeiro, Brazil, where the management of sarcopenia among older adults living with HIV emerged as a hot topic of discussion. Dr. Andre dos Santos from the National Council for Scientific and Technological Development, Brazil, conducted a special study on the correlations between muscle quantity, muscle quality, muscle strength and physical performance in older HIV-positive patients using multimodal imaging techniques. His research findings have drawn widespread attention from clinical peers. Older adults living with HIV suffer prominent skeletal muscle damage due to chronic inflammation and long-term antiretroviral therapy (ART). Traditional assessment models that rely solely on muscle quantity have clear limitations. Infectious Disease Frontier conducted an exclusive interview with Dr. Santos to conduct in-depth discussions on core clinical issues including optimized sarcopenia assessment frameworks and stratified intervention strategies, offering new insights for long-term health management of older adults living with HIV.Infectious Disease Frontier: Previous studies have commonly used muscle mass as the core indicator to assess sarcopenia in older adults living with HIV. This study distinguishes two dimensions: muscle mass and muscle quality. What notable differences exist in the strength of their associations with muscle strength and physical mobility? Which indicator better predicts the risk of physical function decline among older people living with HIV?
Dr. Santos: It is my great honor to share the findings of this study. We deployed multimodal imaging tools including dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI) and ultrasound to evaluate and analyze the respective correlations of muscle quantity and muscle quality. The results demonstrate that muscle quantity metrics measured via DXA, MRI and ultrasound correlate with absolute muscle strength. In contrast, certain markers — particularly the thigh intramuscular fat infiltration index captured by MRI in our research — correlate with total scores on the Short Physical Performance Battery (SPPB).
Infectious Disease Frontier: HIV-associated chronic inflammation and prolonged antiretroviral therapy can both impair skeletal muscle status. Based on the characteristics observed via multimodal imaging, does muscle quality deterioration in older adults living with HIV follow a distinct pathological progression pattern compared with the general elderly population? Can screening based solely on muscle quantity identify high-risk individuals with impaired physical function?
Dr. Santos: This is an extremely valuable research question. Existing literature confirms that HIV infection and long-term ART induce mitochondrial dysfunction in people living with HIV, which in turn triggers muscle loss. The general elderly population also experiences natural age-related muscle quantity loss and reduced muscle strength, a clinical presentation defined as sarcopenia.
While our study did not conduct a direct head-to-head comparison of muscle damage between HIV-positive and HIV-negative older adults, we can confirm that both populations experience muscle quantity loss during aging. However, older adults living with HIV exhibit accelerated aging, resulting in markedly divergent progression patterns of muscle injury compared with uninfected seniors.
For this reason, screening relying solely on muscle quantity fails to adequately identify patients at high risk of physical impairment. Clinicians can quantify muscle volume using DXA, MRI and ultrasound; furthermore, modalities such as MRI enable objective evaluation of muscle quality.
Our research indicates that greater intramuscular fat infiltration corresponds to more severe physical dysfunction. A dual-assessment framework integrating both muscle quantity and quality delivers far more accurate characterization of skeletal muscle damage than single-metric muscle quantity testing alone. This combined approach facilitates early screening and diagnosis of muscle loss, enables precise identification of high-risk populations, closely aligns with older adults’ capacity for independent physical activity, and carries critical implications for clinical prognostic evaluation.
Infectious Disease Frontier: In light of your research outcomes, do we need to revise current sarcopenia assessment protocols for long-term health management of older adults living with HIV? What differentiated strategies should be adopted for exercise intervention and nutritional support for patients presenting distinct subtypes of muscle impairment (isolated muscle quantity deficit versus compromised muscle quality)?
Dr. Santos: Mature sarcopenia diagnostic frameworks are already established for clinical practice. At present, the core diagnostic architecture and assessment criteria applied to people living with HIV remain largely consistent with those for HIV-negative populations, with minor differences in sarcopenia classification cut-off values — the United States has developed dedicated cut-off thresholds specifically for adults living with HIV.
The standard hierarchical logic for sarcopenia diagnosis proceeds as follows: first, assess muscle strength; reduced muscle strength establishes suspected sarcopenia. Second, measure muscle quantity; low muscle mass or abnormal appendicular skeletal muscle index confirms a sarcopenia diagnosis. Third, evaluate physical function to grade sarcopenia severity based on functional performance.
Our research underscores the need to refine existing assessment protocols. Routine clinical sarcopenia workups predominantly use DXA to evaluate muscle wasting, focusing exclusively on quantitative muscle metrics. Yet our data proves that muscle quality bears critical prognostic relevance to physical functional impairment. We therefore recommend incorporating muscle quality evaluation as an additional dimension within the established diagnostic framework to build an enhanced sarcopenia assessment system tailored to older adults living with HIV.
Differentiated intervention strategies constitute another central focus of our research, with clear therapeutic distinctions based on the type of muscle impairment:
– For isolated muscle quantity deficiency: resistance training drives muscle hypertrophy to effectively increase total muscle mass.
– For compromised muscle quality (characterized by elevated intramuscular fat infiltration): a combined regimen of resistance training plus aerobic exercise is required. Aerobic activity reduces intramuscular fat accumulation and ameliorates overall muscle quality.
Nutritional support remains an indispensable component of all intervention protocols. Clinicians should counsel patients to maintain a balanced diet with adequate, well-proportioned protein intake and comprehensive micronutrient supplementation. Collectively, we conclude that older adults living with HIV with skeletal muscle damage require a combined exercise program pairing resistance and aerobic training, alongside personalized balanced nutritional intervention, to deliver targeted, precise clinical management.
