PARAMETERS ASSOCIATED WITH SARCOPENIA IN ELDERLY PATIENTS UNDERGOING MAINTENANCE HEMODIALYSIS

INTRODUCTION

       The global increase in life expectancy has led to a marked rise in the elderly population, consequently increasing the prevalence of age-related health conditions. One such condition is sarcopenia, a progressive syndrome characterized by the loss of skeletal muscle mass, strength, and physical performance. This geriatric syndrome is associated with increased vulnerability to adverse health outcomes such as falls, functional decline, disability, depression, frailty, increased healthcare costs, prolonged care needs, diminished quality of life, and elevated mortality risk.1,2 Among individuals with chronic illnesses, those with chronic kidney disease (CKD) especially those undergoing maintenance hemodialysis (MHD) are particularly susceptible to developing sarcopenia. Long-term hemodialysis treatment is frequently associated with multifactorial complications, with sarcopenia being a major concern due to its direct impact on patient quality of life.1

       The reported prevalence of sarcopenia among elderly individuals varies significantly across studies, ranging from 7% to over 50%. In older adults on hemodialysis, the prevalence is considerably higher, estimated between 37% and 66%.3 Globally, the prevalence among dialysis patients ranges from 20% to 42.2%. These variations may be attributed to differences in diagnostic criteria, methodologies, and study populations. Sarcopenia in the hemodialysis population is not only driven by physiological aging but is also influenced by chronic inflammation, oxidative stress, nutritional deficiencies, and metabolic disturbances related to the dialysis process.4

       The presence of sarcopenia in hemodialysis patients is strongly associated with various adverse outcomes, including an increased risk of falls, recurrent hospitalizations, diminished quality of life, and higher mortality rates.1 In elderly patients undergoing  MHD,  sarcopenia may have even more profound consequences, as it can further deteriorate their functional status. The loss of muscle mass in sarcopenia leads to a decline in physical capabilities, ultimately reducing the patient’s physiological resilience to common hemodialysis-related complications such as infections, malnutrition, and cardiovascular disorders. Consequently, sarcopenia plays a critical role in shaping clinical outcomes in this population. Early identification of factors associated with sarcopenia is essential for timely detection, prevention, and management, particularly among elderly individuals on MHD. Several risk factors have been implicated in the development of sarcopenia, including advanced age, female sex, poor nutritional status, presence of comorbidities, and reduced physical activity. Therefore, it is necessary to investigate parameters that may serve as indicators of these risks, such as age, sex, serum phosphate, calcium, albumin, hemoglobin, nutritional status, and the number of comorbid conditions. In the context of MHD patients, dialysis adequacy has also been recognized as a key factor influencing the development of sarcopenia.

       This study aims to asses the prevalence of sarcopenia and the parameters associated with sarcopenia in elderly patients undergoing MHD. The diagnostic criteria for sarcopenia are based on the 2019 consensus by the Asian Working Group for Sarcopenia (AWGS). The evaluated parameters include serum phosphate, calcium, albumin, hemoglobin levels, nutritional status, age, sex, comorbidities, and dialysis adequacy.

METHODS

Study Design, Setting, Sampling, and Variables

       This was an analytical cross-sectional study conducted at the Hemodialysis Unit of Sanjiwani General Hospital, Gianyar, Bali, Indonesia, in August 2025. Participants were recruited using a consecutive sampling method. Inclusion criteria included patients aged over 60 years old undergoing MHD for more than three months and who provided written informed consent. Exclusion criteria included patients with malignancy, those currently hospitalized, individuals with physical disabilities, and those who routinely used wheelchairs. A total of 49 patients were enrolled in the study. Independent variables included serum phosphate, calcium, albumin, hemoglobin, nutritional status, age, sex, comorbidities, and dialysis adequacy. The dependent variable was sarcopenia.

Ethical Considerations

This study received ethical approval from the Research Ethics Committee of Sanjiwani General Hospital, Gianyar Regency, Bali, Indonesia.

Research Instruments

       The assessment of sarcopenia included measurements of muscle mass, muscle strength, and gait speed. Muscle mass was evaluated using the Bioelectrical Impedance Analysis (BIA) method, specifically with the Omron HBF 375 Karada Scan Body Composition Monitor. The results provided muscle mass percentages, which were then converted using a standard formula to obtain appendicular skeletal muscle mass (ASM) in kg/m². The cut-off values for low muscle mass were  <7.0 kg/m² for men and <5.7 kg/m² for women. Muscle strength was assessed using a handgrip dynamometer to measure the dominant hand's grip strength, with reference values of <28 kg for men and <18 kg for women. Gait speed was measured using a stopwatch over a 6-meter walking distance, with a cutoff value of <1.0 meter/second. A diagnosis of sarcopenia was established if there was a low muscle mass accompanied by either low muscle strength or slow gait speed, or both. Serum phosphate, calcium, albumin, and hemoglobin levels were measured through standard blood laboratory tests. Nutritional status was assessed by measuring height using a stadiometer and weight using a calibrated scale to calculate Body Mass Index (BMI). Comorbidities were identified through medical records, including conditions such as diabetes mellitus, cardiovascular disease, hypertension, urinary tract structural disorders, stroke, and others. Dialysis adequacy was assessed using the Urea Reduction Ratio (URR), calculated with the formula: URR(%)=100x(1-CT/Co), where Ct is the post-dialysis serum urea level and Co is the pre-dialysis serum urea level.

Data Analysis

       Data were analyzed using SPSS software version 18. Descriptive statistics were used to summarize the participants characteristics and the prevalence of sarcopenia. The Chi-Square test or Fisher's Exact test was used to examine associations between categorical variables, such as sarcopenia and nutritional status, sex, and dialysis adequacy. The independent t-test was employed to assess the association between sarcopenia and continuous variables such as serum phosphate, calcium, albumin, hemoglobin, age, and number of comorbidities, provided the data followed a normal distribution and Mann-Whitney U test for non-normally distributed data. Logistic regression analysis was used to identify independent predictors of sarcopenia. A p-value <0.05 was considered statistically significant.

RESULTS

The prevalence of sarcopenia in this study was 57.1%. Participant characteristics are summarized in Table 1.

Tabel 1. Characteristics of the Subject

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  Variable                                           Frequency           Mean (SD)                   Median (range)

                                                            (%)                  

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  Sex

     Male                                             31 (63.3)

     Female                                         18 (37.7) 

  Age (year)                                                                     67,45 (7.35)                 66 (60-90)                                                                

  Dialysis vintage (month)                                                61.24 (48.19)                53 (3-199)

  Nutritional status

     Underwight                                   3  (6.1)

     Normal                                        30 (61.0)

     Overweight                                    3  (6.1)

     Obese                                           13 (26.5)

Sarcopenia

     Yes                                          28 (57.1)

     No                                           21 (42.9)

Phosphat Serum (mg/dL)                                              4.48 (1.47)                4.44 (1.79-7.15) 

Calcium Serum (mg/dL)                                               8.47 (0.52)                8.50 (7.40-9.80)

Albumin Serum (mg/dL)                                              3.70 (0.38)                 3.80 (2.78-4.46)

URR

     Inadequate, < 65%                      17 (34.7)

     Adequate, ≥ 65%                         32 (65.3)

Co-morbid amount

     0                                                17 (34.7)

     1                                                20 (40.8)

     2                                                11 (22.4)

    ≥ 3                                                1 (2.0)

Hemoglobin (mg/dL)                                                      9.95 (0.38)             10.4 (7.10-13.0)                                                

Appendicular skeletal muscle mass/ASM (kg/m2)

     Male                                                                         7.16 (1.52)             6.86 (5.42-12.16)

     Female                                                                     5.63 (1.34)             5.62 (3.01-8.40)                                                

     Total                                                                         6.60 (1.62)             6.58 (3.01-12.16)

Handgrip strength (kg)

     Male                                                                         21.79 (7.02)           21.30 (9.60-35.10)

     Female                                                                     13.06 (6.10)           11.80 (5.80-27.10)

     Total                                                                         18.58 (7.88)           18.60 (5.80-35.10)                                                                                                            

Gait speed (m/sc)

     Male                                                                         1.21 (0.42)             1.08 (0.62-2.55)

     Female                                                                     1.82 (0.93)             1.56 (0.91-4.21)

     Total                                                                         1.44 (0.71)             1.25 (0.62-4.21)                                                

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       Independent t-test showed a statistically significant difference in serum phosphate levels (p = 0.005) and age (p = 0.010) between patients with and without sarcopenia. Chi-square test revealed a significant association between sarcopenia and nutritional status (p < 0.001) as well as dialysis adequacy (p = 0.046).  Logistic regression analysis identified three independent variables significantly associated with sarcopenia, Serum phosphate (p = 0.028, OR = 2.077, 95% CI: 1.080–3.994), dialysis adequacy (p = 0.016, OR = 0.077, 95% CI: 0.010–0.624), and nutritional status (p = 0.008, OR = 0.082, 95% CI: 0.013–0.519). Among these, serum phosphate level had the strongest association with sarcopenia, indicating that higher phosphate levels were protective against sarcopenia in elderly MHD patients.

Tabel 2. Association of Calcium, Phosphat, Albumin, Hemoglobin, Nutritional Status, Co-morbidity, Sex, Age, and URR with Sarcopenia

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        Variables                        _____________Sarcopenia__________                                          p           

                                                 Yes                                         No

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Calcium Serum, mean (SD)      8.50 (SD 0.75)              8.44 (SD 0.45)                                        0.708

Phosphat Serum, mean (SD)     3.99 (SD 1.49)             5.15 (SD 1.19)                                         0.005

Albumin Serum, mean (SD)      3.66 (SD 0.39)             3.78 (SD 0.37)                                         0.273

Hemoglobin, mean (SD)           9.92 (SD 1.39)            10.0 (SD 1.47)                                          0.856

Nutritional status

   Underweight+normal, n(%)   25 (51.0%)                      8 (16.3%)

   Overweight+obese, n(%)        3 (6.1%)                       13 (26.5%)

                                                                                                                                             <0.001

Co-morbidity, mean (SD)        0.86 (SD 0.85)            1.0 (SD 0.78)                                              0.548

Sex

     Male, n(%)                         17 (34.7%)                  14 (28.6%)

     Female, n(%)                      11 (22.4%)                   7 (14.3%)

                                                                                                                                               0.669

Age, mean (SD)                      69.75 (SD 8.40)        64.38 (SD 4.15)                                             0.010

Adequacy (URR)

     Inadequate, n (%)               13 (26.5%)                   4 (8.2%)

     Adequate, n (%)                 15 (30.6%)                  17 (34.7%)

                                                                                                                                               0.046                      

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Tabel 3 Multivariate Analysis Logistic Regression

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Variable                      B                 SE                     p                       Exp(B)                 95% CI

                                                                            Sig                                            Lower-Upper               

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Phosphat Serum        0.731             0.334              0.028                   2.077                1.080-3.994                                              

Adequacy (URR        -2.560             1.066              0.016                   0.077                0.010-0.624

< 65%                       

Nutrutional Status     -2.495            0.938              0.008                  0.082                0.13-0.519

Constant                    -1.129           1.670              0.499                  0.323

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CONCLUSION

       The prevalence of sarcopenia among elderly patients undergoing maintenance hemodialysis (MHD) in this study was 57.1%, indicating a high burden of this condition in this population. The findings demonstrate that low serum phosphate levels, advanced age, malnutrition, and inadequate dialysis adequacy are significantly associated with sarcopenia in elderly MHD patients. Logistic regression analysis revealed that higher serum phosphate levels were protective against sarcopenia, whereas inadequate dialysis and malnutrition substantially increased the risk. These results underscore the importance of a multidisciplinary and integrative clinical approach to prevent and manage sarcopenia in elderly hemodialysis patients. Clinical interventions should focus on optimizing nutritional intake, ensuring dialysis adequacy, and implementing regular assessments of muscle mass and function to improve overall outcomes and quality of life.