The "5-4-3" model for weight management in psychiatric inpatients: a single-arm pre-post evaluation

Comprehensive weight management remains an understudied yet critical component of inpatient psychiatric care, particularly for individuals presenting with overweight or obesity. To address this gap, the present study developed and evaluated the feasibility and preliminary effectiveness of a structured intervention termed the "Five-Discipline, Four-Phase, Three-Support" closed-loop weight management model (5-4-3 Model). In this single-arm pre-post study conducted among psychiatric inpatients at Taizhou Second People's Hospital. We evaluated the model across multiple domains, including weight reduction and maintenance, patient-centered health outcomes, and healthcare team competency.

A single-arm pre-post study was conducted from November 2024 to April 2025. Psychiatric inpatients with a body mass index (BMI) ≥ 24 kg/m² were enrolled. The core intervention was the implementation of the 5-4-3 Model, a multidisciplinary closed-loop management system led by teams from psychiatry, nursing, clinical nutrition, rehabilitation medicine, and clinical pharmacy. The intervention comprised inpatient care (with a length of stay ranging from 1 to 6 months) and a 3-month post-discharge follow-up. Weight at 3-month follow-up was primarily obtained via patient self-report, introducing potential reporting bias. Outcome measures included changes in body weight, BMI, and metabolic indices (extracted from hospital records), patients' weight management knowledge (assessed via a self-administered questionnaire), and staff awareness of weight management protocols and completeness of weight-related data recording. Data were analyzed using paired-sample t-tests.

All 139 enrolled patients completed the 3-month follow-up assessment. Significant reductions were observed in body weight (mean change from admission to 3-month follow-up: -2.95 kg; 95% CI -3.51 to -2.38; p < 0.001) and BMI (mean change: -1.10 kg/m²; 95% CI -1.28 to -0.92; p < 0.001). Patients weight management knowledge scores increased from 27.82 to 53.45% (p < 0.001). Post-intervention improvements were also noted in staff awareness of weight management protocols and the completeness of weight-related documentation.

The 5-4-3 Model suggested preliminary feasibility and was associated with short-term improvements in weight, metabolic markers, and knowledge. However, causal attribution is limited by the uncontrolled single-arm design, and these findings should be considered preliminary. Controlled trials are needed to confirm efficacy.