The term sarcopenia was initially used to describe age-related loss of skeletal muscle mass. Its current definition has been expanded to include muscle loss associated with chronic diseases, physical inactivity or reduced mobility, and malnutrition [1]. Reported prevalence varies widely across studies, ranging from 4% to 68%, largely due to differences in diagnostic criteria, study methodologies, and the populations investigated [2][3]. In patients undergoing dialysis, sarcopenia is associated with a significantly increased risk of mortality [3]. It is also linked to a higher risk of major adverse cardiovascular events and a trend toward increased hospitalization rates in this population [4]. In Africa, particularly in Senegal, sarcopenia among hemodialysis patients remains insufficiently studied. It is within this context that we conducted the present study, with the objective of describing the epidemiological and etiological aspects of sarcopenia in patients receiving hemodialysis.

A total of 152 patients were included in this study (Figure 1). The mean age was 47.88 ± 13.68 years, and 131 patients (86.2%) were younger than 65 years. There were mostly male (77% or 50.7%) yielding a sex ratio of 1.02. Benign nephroangiosclerosis was the underlying cause of kidney disease in 47.4% of cases. The

Figure 1.Flowchart diagram for the selection of the patients.

mean duration of hemodialysis was 7.59 ± 4.45 years. The mean body mass index (BMI) was 20.72 ± 4.91 kg/m² (range: 12.65 - 38.39), and 23.7% of patients had a BMI < 18.5 kg/m². The mean serum ferritin level was 829.73 ± 778.4 pg/mL (Table 1). Based on the SARC-F questionnaire, sarcopenia was suspected in 55 patients. Handgrip strength was reduced in 82 patients (53.94%), including 38 men and 44 women. Bioelectrical impedance measurements confirmed sarcopenia in 64 patients, corresponding to a prevalence of 42.10% (95% IC: [34.4% - 50.10%]), including 21 women and 43 men. Thirty patients presented with severe sarcopenia. In bivariate analysis, the factors associated with sarcopenia were sex (p = 0.001) and BMI > 25 (p < 0.0001), BMI < 18.5 (p < 0.0001) (Table 2).

In multivariate analysis, factors independently associated with sarcopenia were male sex (OR = 5.98; 95% CI: 2.27 - 15.74), undernutrition (BMI < 18.5) (OR = 6.25; 95% CI: 2.08 - 18.74), and overweight (BMI > 25) (OR = 0.06; 95% CI: 0.01 - 0.49) (Table 3).

Table 1. Clinical parameters and biochemical indicators of patients with or without sarcopenia.

Table 2. Results of bivariate analaysis.

PTH: Parathyroid hormone; BMI: Body mass index.

Table 3. Factors associated with sarcopenia (multivariable analysis).

BMI: Body mass index.

In our study conducted among patients undergoing chronic hemodialysis, the prevalence of sarcopenia was 42% according to the EWGSOP2 criteria. This prevalence lies at the upper end of the range reported in the international literature, where values generally vary between 20% and 60%, depending on the diagnostic criteria and assessment methods used [7]. African studies on sarcopenia in hemodialysis patients remain scarce. The only study that formally assessed sarcopenia in an African center, conducted by Crystal et al. (2024) in sub-Saharan Africa, reported a prevalence of only 4.1%, which is markedly lower than our findings [8]. In Asia, several studies have reported prevalences ranging from 28% to 60%, particularly when sarcopenia is diagnosed using the EWGSOP2 criteria or those of the Asian Working Group for Sarcopenia (AWGS), with the inclusion of muscle strength assessment [9]-[11]. In Europe and North America, prevalences generally range between 22% and 50%, with higher values observed in older populations, patients with diabetes, or those with longer dialysis vintage. One of the major factors explaining the wide variability in sarcopenia prevalence across studies is the heterogeneity of diagnostic definitions applied. Some studies use the EWGSOP2 criteria, others rely on the AWGS criteria, while others still use older or non-standardized definitions [7][12][13]. Beyond the definition itself, the method used to assess muscle mass or muscle function plays a decisive role. Techniques such as dual-energy X-ray absorptiometry (DEXA), imaging modalities (MRI/CT), bioelectrical impedance analysis, or the use of handgrip strength and functional performance tests may yield substantially different results depending on hydration status, nutritional status, inflammatory state, and the timing of assessment relative to the dialysis session (pre- or post-dialysis) [7][13]. In hemodialysis patients, inter- and intra-dialytic fluid shifts can markedly influence the estimation of muscle mass (lean mass, fat-free mass) when using bioelectrical impedance analysis or DEXA. These fluctuations may lead to an underestimation of muscle mass, thereby biasing the estimation of sarcopenia prevalence. In our study, measurements were performed under stabilized conditions (post-dialysis), which may partly explain the relatively high prevalence of 42%. Conversely, studies using less sensitive methods or non-standardized measurement conditions may underestimate sarcopenia, thus reporting lower prevalence rates [14]. Other factors may also account for these variations in prevalence. When the study population is globally older, a higher prevalence of sarcopenia is expected. Several studies have identified dialysis vintage as an independent risk factor [10][15]; the longer a patient has been on dialysis, the more dialysis-related factors (chronic inflammation, protein catabolism, comorbidities, etc.) accumulate and promote muscle loss. In addition, African populations and those from low-resource settings are underrepresented in the literature, which limits the generalizability of published results. These biases may lead to either underestimation or overestimation of sarcopenia prevalence depending on the context. In multivariate analysis, factors independently associated with sarcopenia were male sex (OR = 5.98; 95% CI: 2.27 - 15.74), undernutrition (BMI < 18.5) (OR = 6.25; 95% CI: 2.08 - 18.74), and overweight (BMI > 25) (OR = 0.06; 95% CI: 0.01 - 0.49). We found that men were at higher risk of sarcopenia in our cohort. This finding is consistent with several published data. In a recent large review, male sex frequently emerged as a risk factor for sarcopenia in dialysis patients [7][10][16]. Several pathophysiological hypotheses may explain this association: Hormonal differences men partly rely on anabolic hormones, particularly testosterone, to maintain muscle mass. In the context of end-stage kidney disease and hemodialysis, hormonal decline—especially uremic hypogonadism—is common and may promote muscle catabolism; Greater baseline muscle mass in men inflammatory and metabolic catabolism may result in a more pronounced or more rapid loss of muscle mass and function in men compared with women; Therefore, male sex should be considered a risk marker in screening programs, as it may help identify a vulnerable population requiring targeted interventions; BMI < 18.5 kg/m² (undernutrition) low BMI was a significant risk factor in our study. This association is well documented in the literature. Several studies have demonstrated a link between malnutrition, the malnutrition-inflammation complex, and sarcopenia in dialysis patients [17]-[19]. A study using a “sarcopenia index” derived from nutritional parameters showed that protein-energy wasting is a strong predictor of muscle loss and muscle weakness in older patients on hemodialysis [20][21]. Several mechanisms may explain this relationship: insufficient or inadequate protein intake in the context of chronic kidney disease and dialysis, due to amino acid losses, albumin loss, and poor nutritional intake [22][23]; negative nitrogen balance, reduced protein synthesis, and increased muscle catabolism, exacerbated by chronic inflammation, metabolic acidosis, and dialysis-related losses [7][10].

A BMI > 25 kg/m² may appear protective against sarcopenia in hemodialysis patients, as it often reflects greater energy reserves and a lower risk of undernutrition. However, BMI should be interpreted with caution, as it does not distinguish between fat mass and muscle mass [16]. Thus, a BMI > 25 may mask overweight or sarcopenic obesity (excess fat with reduced muscle mass), highlighting the need for a structured assessment. In accordance with the EWGSOP2 consensus, interpretation should integrate muscle strength, muscle quantity/quality, and physical performance, beyond BMI alone [5].

Sarcopenia is common among hemodialysis patients in Dakar. Male sex, and undernutrition were identified as significant risk factors. A prospective cohort would help assess temporal and prognostic relationships, while the current cross-sectional design already estimates prevalence. This study has several limitations. First, its cross-sectional design precludes the establishment of causal relationships between the identified associated factors and the development of sarcopenia. Second, a potential selection bias should be acknowledged, as patients unable to stand for bioelectrical impedance analysis, those with cardiac pacemakers, or those unable to complete the questionnaire were excluded. This may have led to an underestimation of the true prevalence of sarcopenia by systematically excluding more frail individuals. Finally, several potential confounding factors were not comprehensively assessed, including physical activity level, actual nutritional intake, inflammatory markers such as C-reactive protein, hormonal status (e.g., testosterone), and dialysis adequacy (Kt/V), which may have influenced the observed associations.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

The authors declare that the work described was carried out in accordance with the World Medical Association’s Code of Ethics (Declaration of Helsinki) applicable to studies involving human subjects. The study protocol was approved by the local Ethics Committee under approval number CEH-DJ/2025/021.