# Evaluating the effectiveness of sociotherapy following psychiatric hospitalization: a target trial emulation protocol using German statutory health insurance data

## TL;DR

This study aims to evaluate how effective sociotherapy is in reducing psychiatric hospital readmissions using real-world data from Germany's health insurance system.

## Contribution

The study introduces a target trial emulation framework to assess sociotherapy's impact on psychiatric readmissions in a real-world setting.

## Key findings

- Sociotherapy's effect on 30-day psychiatric readmission rates will be evaluated using claims data.
- Secondary outcomes include 365-day readmission rates and total hospitalization days.
- Propensity score methods will reduce bias in the observational study design.

## Abstract

The German health care system maintains a strict division between inpatient and outpatient care, posing challenges for the continuity of care. Discharge management facilitates the transition from inpatient to outpatient settings. For psychiatric patients, sociotherapy is one transitional intervention that can be prescribed to inpatients at discharge and then provided in the outpatient setting. As a form of case management, it aims to motivate patients, coordinate care among providers, and ultimately reduce psychiatric hospital readmissions. However, the effectiveness of sociotherapy remains unclear due to a lack of randomized trials. This protocol describes an observational study investigating the causal impact of sociotherapy on psychiatric readmission rates.

We will use claims data from the largest statutory health insurance provider in Germany to evaluate the effect of sociotherapy as a discharge management measure on 30-day readmissions among patients who received psychiatric inpatient treatment. To reduce potential bias in this observational study we will use the target trial emulation framework. Quasi-randomization will be achieved through Propensity Score based methods, controlling for characteristics of the index event, patients' medical history, and relevant sociodemographic factors. Intention to treat and per protocol effects will be estimated with logistic regression models. Furthermore, we will analyze 365-day readmission rates, time to first psychiatric hospitalization within 365 days, total number of psychiatric hospitalizations within 365 days, and cumulative number of days in hospital due to psychiatric admissions within 365 days as secondary outcomes.

Our study will evaluate the effectiveness of sociotherapy as a transitional intervention following psychiatric hospitalization. By employing the Target Trial Emulation framework, we aim to generate robust, real-world evidence that can guide both clinical practice and policy-making, ultimately contributing to improved continuity of care for psychiatric patients.

Trial registration: DRKS, ISRCTNDRKS00035987. Registration on 17 February 2025—Retrospectively registered, https://drks.de/register/de/trial/DRKS00035987

The online version contains supplementary material available at 10.1186/s12913-025-13137-2.