Depressive symptom heterogeneity among older adults after hip fracture.

Objective: to evaluate patterns of depressive symptoms after hip fracture and examine their impact on functional recovery.

Methods: participants (n = 304) included older adults from the Baltimore Hip Studies 7th cohort who experienced a hip fracture. Depressive symptoms were measured at baseline or 2-, 6- or 12-month post-hip fracture using the 20-item Center for Epidemiologic Studies Depression scale. Gait speed was measured after hip fracture at 2-, 6- or 12-month follow-up. Latent class analysis was used to identify individuals with similar patterns of depressive symptoms after hip fracture. Item response probabilities characterised symptom profiles, and posterior probability estimates were used to assign participants to a baseline depressive symptom subtype. Weighted estimated equations compared post-fracture gait speed between baseline symptomatic and asymptomatic groups.

Results: four patterns of depressive symptoms were identified: asymptomatic (50.8%), somatic (28.6%), melancholic (11.4%) and anhedonic (9.2%). The somatic subtype was characterised by difficultly concentrating and reduced energy and movement, whereas anhedonic symptoms were associated with the inability to experience pleasure. Melancholic symptoms corresponded to anhedonia, decreased physical activity and other psychological and somatic complaints. Compared with the asymptomatic group, somatic symptoms were consistently associated with slower gait speed, -0.03 metres per second (m/s) and between-group differences for melancholic symptomology were as large as -0.05 m/s, but the associations were not statistically significant.

Conclusion: findings demonstrate unique depressive symptom subtypes in older adults after hip fracture and provide confirmatory evidence of unique clinical phenotypes; however, their impact on functional recovery after hip fracture remains unclear.