Correlation between serum phosphorus level and sarcopenia in patients with type 2 diabetes mellitus

Sarcopenia is associated with poor prognosis of type 2 diabetes mellitus (T2DM). Phosphorus (P) deficiency may lead to disturbance of the musculoskeletal system and serve as a potential biomarker of sarcopenia. This study aimed to evaluate the correlation of P and muscle mass in T2DM patients. A total of 1078 T2DM inpatients were recruited. Skeletal muscle index (SMI), along with subtypes of obesity were quantified using a dual energy X-ray absorptiometry. Participants were considered as sarcopenia, when SMI was less than 7.0 kg/m ² in males and 5.4 kg/m ² in females. Clinical information and biochemical characteristics were measured and recorded. We found the prevalence of low muscle mass was 20.2% and 13.6% in male and female patients, respectively. Serum P index was associated with a reduced risk of low muscle mass in both genders. This finding was observed before and after adjustment for variables, including for age, A/G ratio, SBP, DBP, duration of diabetes, Ca, FPG, TC, TG, HDL, and LDL. Potentially, there might be nonlinear association between P index and SMI. When the P index was ≤ 0.98, a significant positive correlation with SMI was observed in males. However, when the P index was > 0.98, no significant correlation between P index and SMI. Similarly, in females, P index was positively correlated with SMI when P index was ≤ 1.04, while when P index was > 1.04, a weak and non-significant negative correlation between P and SMI was observed. In conclusion, serum P level is inversely correlated with sarcopenia in T2DM patients.