A total of 2613 individuals were enrolled in our analysis, with a median age of 48 years (range: 18–91 years), including 1614(61.8) males and 999(38.2) females. The median values of BMI, ASM and SMI were 23.81(15.05–43.02), 20.14(8.9-32.98) and 7.27(4.35–11.50), respectively. In terms of lipid profile, the median values of TC, LDL, HDL and TG were 199.87(85.83-402.84), 119.85(30.54-301.16), 45.23(17.40-108.25) and 127.44(35.40-1896.56), respectively. Other demographic and clinical characteristics were displayed in Table 1. According to AWGS 2019 consensus, a total of 362(13.9%) subjects were diagnosed as sarcopenia.
Optimal cutoff of TG/HDL ratio and association between TG/HDL ratio and clinicopathological factors
As pre-processing, ROC curves were utilized to evaluate the performances of TG, HDL, and TG/HDL ratio, and to discover corresponding cut-offs for sarcopenia diagnosis. As Fig. 1 showed, the cutoffs for TG(mg/dl), HDL(mg/dl), and TG/HDL ratio were 138.502 mg/dl(sensitivity: 0.718; specificity: 0.481), 42.719 mg/dl(sensitivity: 0.776; specificity: 0.439) and 2.775(sensitivity: 0.671; specificity: 0.546) respectively.
The AUC for TG(mg/dl), HDL(mg/dl), and TG/HDL ratio were 0.626(p < 0.001), 0.637(p < 0.001), 0.644(p < 0.001), respectively. Based on Youden index and AUC, we selected the TG/HDL ratio as optimal indicator. Individuals were divided into 2 groups: TG/HDLlow group(TG/HDL ratio < 2.775) and TG/HDLhigh group(TG/HDL ratio ≥ 2.775).
There were 1266 subjects with low TG/HDL ratio(< 2.775) and 1347 subjects with high(TG/HDL ratio ≥ 2.775). The association between TG/HDL ratio and clinical variables were summarized in Table 1. Compared with TG/HDLlow group, TG/HDLhigh group showed higher BMI(p < 0.001), ASM(p < 0.001), SMI(p < 0.001), with more elders(p = 0.001) and males(p < 0.001) in this group. In view of blood and biochemical parameters, TG/HDLhigh group displayed higher values of FPG(p < 0.001), HbA1c(p < 0.001), UA(p < 0.001), TC(p < 0.001), LDL(p < 0.001), TG(p < 0.001), UA(p < 0.001), albumin(p = 0.002), WBC(p < 0.001) and Hb(p < 0.001), and lower values of HDL(p < 0.001). In consideration of clinical parameters, there were more current smokers(p < 0.001), heavy drinkers(p < 0.001), and DM(p < 0.001), HTN(p < 0.001) and hyperuricemia(p < 0.001) patients, existing in TG/HDLhigh group.
Univariable and multivariable logistic regression analyses
Variables having effects on sarcopenia were identified by the univariable and multivariable logistic regression analyses, and the results were listed in Table 2. In the univariate logistic regression analysis, factors including age[> 65 vs. ≤65, odds ratio(OR): 1.888, 95% confidence interval(95%CI): 1.319–2.703], gender(male vs. female, OR: 1.775, 95%CI: 1.420-2,219), heavy drink(yes vs. no, OR: 0.700, 95%CI: 0.490-1.000), DM(yes vs. no, OR: 0.708, 95%CI: 0.468–1.073), HTN(yes vs. no, OR: 0.757, 95%CI: 0.584–0.983), hyperuricemia(yes vs. no, OR: 0.564, 95%CI: 0.419–0.758), overweight(yes vs. no, OR: 0.031, 95%CI:0.015–0.065) and TG/HDL ratio(high vs. low, OR: 0.408, 95%CI: 0.323–0.516), showed significant association with sarcopenia and were subsequently brought into multivariable analysis. As Table 2 showed, age(> 65 vs. ≤65, OR: 2.100, 95%CI: 1.427–3.089), overweight(yes vs. no, OR: 0.035, 95%CI: 0.016–0.074) and TG/HDL ratio(high vs. low, OR: 0.631, 95%CI: 0.494–0.806) still remained the independent effects on sarcopenia with statistical significance. The C-index for this multivariable analysis model was 0.732.
There were confounding factors existing in this study, including age and overweight, as Table 2 showed. In addition, gender might be a confounding factor, as Chung et al. proposed that TG/HDL ratio was associated with sarcopenia in elderly Korean males. Thus, in our study, we chose these 3 factors and conducted further subgroup analyses, which was displayed in Fig. 2.
In age < 65 subgroup, more subjects were diagnosed with sarcopenia in TG/HDLlow group than in TG/HDLhigh group[216 of 1161 subjects(18.6%) vs. 100 of 1223(8.2%)]. No matter in male[94 of 564 subjects(16.7%) vs. 86 of 1050(8.2%)] subgroup or in female[149 of 702 subjects(21.2%) vs. 33 of 297(11.1%)], TG/HDL ratio remained the independent effect. In non-overweight population[240 of 1026 subjects(23.4%) vs. 115 of 701(16.4%)], more subjects in TG/HDLlow group tend to be diagnosed with sarcopenia. The effect of TG/HDL ratio on status of sarcopenia was favorable (HR < 1.0) across a majority of prespecified subgroups, except age ≥ 65(HR: 0.523, 95%CI: 0.271–1.007) and overweight(HR: 0.492, 95%CI: 0.109–2.216) population.
Correlation between TG/HDL ratio and prevalence of sarcopenia
Individuals were stratified by quartiles into Q1, Q2, Q3 and Q4 groups, respectively. Figure 3 displayed the prevalence of sarcopenia of each group. The prevalence of sarcopenia decreased significantly as TG/HDL ratio increased(p < 0.001): 22.6% of Q1, 15.0% of Q2, 10.3% of Q3 and 7.4% of Q4, respectively.