Results
low back pain, LBP
Data on adherence and received treatment during the study were available for 191 of the 208 participants. The unavailability of adherence data for a patient was caused by physical therapists not using the case report form properly during treatment or not returning the case report form to the researchers after the treatment ended. Eighteen patients received fewer than 3 treatments, leaving data from 173 participants available for analysis.Data on patient adherence were collected during 5.1 (SD 2.5) treatment sessions and total treatment duration lasted for 51 (SD 41.7) days. Baseline characteristics of included patients can be found in Baseline Demographic and Clinical Characteristics for all PatientsBMI = body mass index; IQR = interquartile range; LBP = low back pain.
Overall mean adherence trajectory estimated from 52 imputed datasets (thick gray), mean adherence trajectory estimated from each of the 52 imputed datasets separately (thin gray), and mean adherence trajectory of the imputed dataset (#24) with the smallest mean deviation from the overall mean adherence trajectory (black).Models with 1 to 4 classes were estimated using LCGA. The addition of a quadratic term for time did not increase the fit of the linear models. The 4-class solution showed optimal performance based on the maximum log-likelihood criterion, with a value of −3115.1, while the 2-class and 3-class models yielded lower log-likelihood scores of −3126.3 and − 3119.1, respectively. Similarly, the Akaike Information Criterion favored the 4-class solution with a value of 6254.2, compared to the 2-class (6264.7) and 3-class (6256.3) models. Conversely, the Bayesian Information Criterion favored the 2-class model with a lower value of 6283.6, in contrast to the 3-class (6284.6) and 4-class (6292.0) models. Furthermore, the entropy measure indicated a better fit for the 2-class model (0.61) compared to the 3-class (0.49) and 4-class (0.54) models. However, the 2-class model displayed 2 nearly parallel trajectories (Predicted trajectories of adherence over time based on class assignment for the 1-class (black), 2-class (gray), 3-class (gray/dash), and 4-class (gray/dot-dash) trajectory models.Estimated trajectories for the 3-class trajectory model with 95% CI.Baseline characteristics of the patient groups for each trajectory class are shown in Comparison Between Identified Trajectory Classes Based on Baseline Characteristics% = percentage of the total sample; BMI = body mass index; IQR = interquartile range; LBP = low back pain.
