Longitudinal clusters of pain and stiffness in polymyalgia rheumatica: 2-year results from the PMR Cohort Study

Muller, Sara; Whittle, Rebecca; Hider, Samantha L; Belcher, John; Helliwell, Toby; Morton, Chris; Hughes, Emily; Lawton, Sarah A; Mallen, Christian D

Abstract

Objectives. To investigate potential subgroups of primary care diagnosed patients with polymyalgia rheumatica (PMR) based on self-reported pain and stiffness severity over time.

Methods. 652 people with an incident PMR diagnosis were recruited from English general practices and completed a baseline postal questionnaire. They were followed-up with a further six questionnaires over a two-year period. 446 people completed 2-year follow-up. Pain and stiffness were reported on 0-10 numerical rating scales. Latent class growth analysis was used to estimate the joint trajectories of pain and stiffness overtime. A combination ofstatistical and clinical considerations was used to choose the number of clusters. Characteristics of the classes were described.

Results. Five clusters were identified. One cluster represented the profile of ‘classical’ PMR symptoms and one represented sustained symptoms that may not be PMR. The other three clusters displayed a partial recovery, a recovery followed by worsening and a slow, but sustained recovery. Those displaying classical PMR symptoms were in better overall health at diagnosis than the other groups.

Conclusions. PMR is a heterogeneous condition, with a number of phenotypes. The spectrum of presentation, as well as varying responses to treatment, may be related to underlying health status at diagnosis. Future research should seek to stratify patients at diagnosis to identify those likely to have a poor recovery and in need of an alternative treatment pathway. Clinicians should be aware of the different experiences of patients and monitor symptoms closely, even where there is initial improvement.

Citation

Muller, S., Whittle, R., Hider, S. L., Belcher, J., Helliwell, T., Morton, C., …Mallen, C. D. (2020). Longitudinal clusters of pain and stiffness in polymyalgia rheumatica: 2-year results from the PMR Cohort Study. Rheumatology, 59(8), 1906-1915. https://doi.org/10.1093/rheumatology/kez533

• Journal Article Type: Article
• Acceptance Date: Oct 6, 2019
• Online Publication Date: Nov 19, 2019
• Publication Date: 2020-08
• Publicly Available Date: May 26, 2023
• Journal: Rheumatology
• Print ISSN: 1462-0324
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 59
• Issue: 8
• Pages: 1906-1915
• DOI: https://doi.org/10.1093/rheumatology/kez533
• Keywords: polymyalgia rheumatica, pain, stiffness, clusters, prognosis
• Publisher URL: https://doi.org/10.1093/rheumatology/kez533