Heterogeneity in Temporal Ordering of Depression and Participation After Traumatic Brain Injury

Abstract

Objective: To examine heterogeneity in the temporal patterns of depression and participation over the first 2 years post traumatic brain injury (TBI).

Design: Observational prospective longitudinal study.

Setting: Inpatient rehabilitation centers, with 1- and 2-year follow-up conducted primarily by telephone.

Participants: Persons with TBI (N=2307) enrolled in the Traumatic Brain Injury Model Systems database, followed at 1 and 2 years post injury.

Interventions: Not applicable.

Main outcome measure: Patient Health Questionnaire-9 (PHQ-9) and Participation Assessment With Recombined Tools-Objective (PART-O).

Results: Using latent class modeling we examined heterogeneity in the longitudinal relationship between PHQ-9 and PART-O. The identified 6 classes were most distinct in terms of (1) level of PHQ-9 score and (2) association between the year 1 PART-O score and year 2 PHQ-9 score. For most participants, PART-O at year 1 predicted PHQ-9 at year 2 more than the reverse. However, there was a subgroup of participants that demonstrated the reverse pattern, PHQ-9 predicting later PART-O, who were on average, older and in the "other" employment category.

Conclusions: Results suggest that links between participation and depression are stronger for some people living with TBI than for others and that variation in the temporal sequencing of these 2 constructs is associated with demographic characteristics. These findings illustrate the value in accounting for population heterogeneity when evaluating temporal among outcome domains.

Keywords: Brain injuries; Depression; Latent class analysis; Mental health; Rehabilitation.