# Multivariate Trajectories of Weight and Mental Health and Their Prognostic Significance 6 Years After Obesity Surgery

## TL;DR

This study explores how weight and mental health change over six years after obesity surgery and finds that early improvements may predict long-term outcomes.

## Contribution

The study introduces multivariate trajectory analysis to link weight and mental health changes with long-term health outcomes after obesity surgery.

## Key findings

- Three trajectory classes of sustainability were identified after obesity surgery, with differing long-term health outcomes.
- Multivariate trajectory modeling showed greater predictive value than univariate weight modeling for health outcomes.
- Early improvements in weight and mental health may indicate a need for continued clinical attention to prevent relapse.

## Abstract

Obesity surgery (OS) results in substantial, albeit heterogeneous, long‐term improvements in weight and mental health, with unclear trajectories and their associations. This study examined multivariate trajectories of weight, psychopathology, and health‐related quality of life (HRQOL) after OS, and their prospective association with long‐term health outcomes.

In the prospective multicenter Psychosocial Registry of Obesity Surgery, N = 856 patients were classified into multivariate trajectory classes using latent class linear mixed models, based on assessments of weight, depression, eating disorder psychopathology, and HRQOL at baseline and annually 1–5 years following OS. The prognostic significance of trajectory classes for 6‐year follow‐up was examined. Multivariate trajectory modeling was compared with univariate weight trajectory modeling for concordance and prognostic significance.

We identified three trajectory classes of low (I, 2.8%), medium (II, 89.1%), and high (III, 8.1%) sustainability 1–5 years after OS, indicating high (I) or gradual deterioration (II) or further improvement (III) after initial improvement of indicators. The low sustainability class (I) reached nadir improvements earliest. Consistently, trajectory classes were prospectively associated with differential clinically significant improvement in weight and mental health at the 6‐year follow‐up. Multivariate trajectory modeling was discordant with univariate weight trajectory modeling and showed greater predictive value for health outcomes at the 6‐year follow‐up.

Patients who achieve nadir improvements in weight and mental health early may require clinical attention to prevent long‐term relapse. Monitoring changes in the first years after OS appears essential to identify patients in need of additional intervention, ideally using indicators beyond weight, such as mental health.