Illness Perceptions as a Predictor of Symptom Cluster Trajectories in Patients With Inflammatory Bowel Disease: A Latent Growth Mixture Model.

ABSTRACT

The aims of this study were to (a) identify the trajectory of symptom clusters in patients with inflammatory bowel disease up to 28 weeks after initiation of infliximab therapy and (b) examine the illness perceptions associated with symptom cluster trajectories. This was a prospective study where participants completed the symptom cluster scale at baseline, 14 weeks, and 28 weeks. A latent growth mixture modeling was used to identify trajectories of symptom clusters that were predicted, using baseline covariates (Brief Illness Perception Questionnaire). A total of 206 patients were included and identified as three latent classes moderate symptom cluster-stable decline group (C1), high symptom cluster-rapid decline group (C2), and stable symptom cluster-stable trend group (C3). C1 was predicted by cognitive illness perceptions (odds ratio [95% confidence interval] 1.134 [1.071, 1.200], p < .001). C2 was also predicted by cognitive and emotional illness perceptions (odds ratio [95% confidence interval] 1.169 [1.095, 1.248], p < .001; odds ratio [95% confidence interval] 1.174 [1.038, 1.328], p = .011). Patients with inflammatory bowel disease, initiating infliximab therapy, had different symptom cluster trajectories. Illness perceptions were associated with symptom cluster classes, which underline the complexity of symptoms. Paying attention to these factors and providing necessary knowledge and psychological supporting care after infliximab therapy would effectively improve patients' symptom burden.