Frequency of therapeutic drug monitoring in inpatient precision depression care and duration of hospitalization

AI Summary

TDM frequency ≥0.66/week (about biweekly) associated with a mean 21 day reduction in hospitalisation duration (p < 2.2×10−16).
Higher TDM frequency correlated with increased therapy adjustments within seven days, including dose adaptations and drug initiation or discontinuation.
Patients with TDM ≥0.66/week achieved a 37% reduction in hospitalisation costs, supporting cost-effectiveness of biweekly integrated TDM.

TL;DR (AI Generated)

In psychiatry, therapeutic drug monitoring (TDM) is routinely used to improve treatment safety and efficacy, yet its association with hospitalization duration and cost-effectiveness remains unclear.

Receiver operating characteristic analysis identified a minimum effective TDM frequency of 0.66/week, which was associated with a mean reduction in hospitalization duration of 21 days (p < 2.2*10-¹⁶).

In conclusion, frequent, clinically integrated TDM of antidepressants and timely treatment adaptations were associated with shorter hospitalization and reduced hospitalization costs.

Basic summary

Transl Psychiatry. 2026 Aug 1;16(1):387. doi: 10.1038/s41398-026-04316-8.

ABSTRACT

In psychiatry, therapeutic drug monitoring (TDM) is routinely used to improve treatment safety and efficacy, yet its association with hospitalization duration and cost-effectiveness remains unclear. We hypothesized that the frequency of routinely requested TDM is associated with hospitalization duration. In this retrospective study, patients with major depressive disorder receiving TDM of antidepressants between 2015 and 2021 (N = 383) were analyzed. Inclusion criteria were a hospital stay ≥7 days and a first TDM request at admission. Regression analyses assessed associations between TDM frequency and hospitalization duration. Receiver operating characteristic analysis identified a minimum effective TDM frequency of 0.66/week, which was associated with a mean reduction in hospitalization duration of 21 days (p < 2.2*10^–¹⁶). The upper effective threshold was approximated at 1.3/week. Higher TDM frequency was associated with more therapy adjustments within 7 days after TDM, including dose adaptations (p = 3.07*10^–¹⁶) and drug initiation/discontinuation (p = 6.70*10^-6). Drug-specific analyses for amitriptyline, venlafaxine, and mirtazapine confirmed these associations. Cost-effectiveness analysis demonstrated a 37% cost reduction for patients with TDM frequencies ≥0.66/week. In conclusion, frequent, clinically integrated TDM of antidepressants and timely treatment adaptations were associated with shorter hospitalization and reduced hospitalization costs. These findings suggest that at least biweekly TDM combined with subsequent treatment adaptations may represent a previously underappreciated strategy to improve clinical and economic outcomes in a tertiary referral center for severe major depression. Whether these findings are transferable to other inpatient and outpatient settings of depression care requires further studies.

PMID:42538328 | DOI:10.1038/s41398-026-04316-8

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