Objective
To identify latent subgroups among patients with Achilles tendinopathy, describe patient characteristics and clinical attributes that defined each subgroup, and develop a clinical classification model for subgroup membership.
Design
Cross-sectional study.
Methods
145 (73 men) participants (age (mean±SD) 51±14 years) with clinically diagnosed Achilles tendinopathy completed a baseline evaluation including demographics and medical history, patient-reported outcome measures, clinical exam, tendon structure measures using ultrasound imaging and continuous shear wave elastography, and a functional test battery. Subgroups were identified using Mixture Modeling. We compared the subgroups using one-way ANOVA or Chi-Square tests and Tukey’s post-hoc test to identify defining attributes. We developed a clinical classification model using logistic regression and Receiver Operating Characteristics (ROC) curves.
Results
Three latent subgroups were identified and named by their distinctive patient characteristics and clinical attributes. Activity-dominant (n=67) on average had the highest physical activity level, function, and quality of life, reported mild symptoms, and were youngest. Psychosocial-dominant (n=56) on average had the worst symptoms, impaired function, heightened psychological factors, poorest quality of life, minimal tendon structural alterations, and were obese and predominately female. Structure-dominant (n=22) on average had the most tendon structural alterations, severe functional deficits, moderate symptoms and psychological factors, reduced quality of life, were the oldest, obese, and predominately male. The clinical classification model correctly classified 85% (123/145) of participants.
Conclusion
Three Achilles tendinopathy subgroups (activity-dominant, psychosocial dominant, structure-dominant) differed in patient characteristics and clinical attributes.
Click to expand...