Fig. 3

Forest plots for the stratified analysis of the subgroups. A stratified analysis of the subgroups revealed that when HR = 1 in the low-level SII subgroup, the risk of fragility fractures increased significantly, with increases of 2.708 times in the BMI < 24 subgroup (P = 0.022, P for trend = 0.021), 1.439 times in the hypertension subgroup (P = 0.017, P for trend = 0.016), 4.15 times in the anemia subgroup (P = 0.01, P for trend = 0.008), and 2.439 times in the DPN subgroup (P = 0.004, P for trend = 0.004), which indicated that the SII was positively correlated with the risk of fragility fractures. Additionally, stratification by subgroup did not affect the ability of the SII to predict the risk of fragility fractures in the whole study population (all P values for interactions > 0.05), demonstrating that these stratification factors were not confounding factors