This study included 108 patients and divided them into multiple categories to analyze the efficacy and side effects according to whether their renal function was impaired and whether there was TDM intervention to adjust the dosage.
A comparative analysis based only on the "presence or absence" of renal function impairment (RI group vs non-RI group) shows that if both are taken at a fixed dose (600mg/12h), the median Cmin value of the RI patient group (25.6 ± 10.4 mg/L) was twice that of the non-RI group (14.1 ± 8.8 mg/L), and its treatment maintenance time was shorter than that of the non-RI group (16 days vs 21 days). Most importantly, 62.9% of patients in the RI group developed thrombocytopenia, compared with only 31.3% in the non-RI group.
A comparative analysis based on interventional dose adjustment with or without TDM (TDM group vs. non-TDM group) found that the treatment duration of the TDM group was significantly longer than that of the non-TDM group, but the difference in the probability of failure due to persistent infection between the TDM group and the non-TDM group was not statistically significant. Combined with the influencing factors of RI, it can be seen that in the non-RI group, there is no significant difference in the failure rate between the two groups. While in the RI group, overall failure and hematological toxicity were relatively significantly lower in the TDM group, although there were no significant differences in patient general characteristics, baseline hematological parameters, and concomitant drug therapy.
In the TDM group, 90.5% of episodes in the RI group required dosage adjustments to avoid potential linezolid overexposure, compared with only 62.9% in the non-RI group (P = 0.031). In the TDM interventional therapy group, if the dose was adjusted from 600 mg/12h to 300 mg/12h, the corresponding Cmin was still ≥ 2.0 mg/L, and insufficient linezolid exposure did not occur. Supplementary analysis of 53 episodes showed that using standard dosage for 2 days was enough to quickly reach the effective therapeutic concentration in the RI group, and then using the 300mg/12h strategy, Cmin could still be maintained above the effective exposure