Cluster analysis identifies unmet healthcare needs among patients with rheumatoid arthritis

To identify the patterns of healthcare resource utilization and unmet needs of persistent disease activity, pain, and physical disability in rheumatoid arthritis (RA) by cluster analysis.

Patients attending the Jyväskylä Central Hospital rheumatology unit, Finland, were, from 2007, prospectively enrolled in a clinical database. We identified all RA patients in 2010-2014 and combined their individual-level data with well-recorded administrative data on all public healthcare contacts in fiscal year 2014. We ran agglomerative hierarchical clustering (Ward's method), with 28-joint Disease Activity Score with three variables, Health Assessment Questionnaire index, pain (visual analogue scale 0-100), and total annual health service-related direct costs (€) as clustering variables.

Complete-case analysis of 939 patients derived four clusters. Cluster C1 (remission and low costs, 550 patients) comprised relatively young patients with low costs, low disease activity, and minimal disability. C2 (chronic pain, disability, and fatigue, 269 patients) included those with the highest pain and fatigue levels, and disability was fairly common. C3 (inflammation, 97 patients) had rather high mean costs and the highest average disease activity, but lower average levels of pain and less disability than C2, highlighting the impact of effective treatment. C4 (comorbidities and high costs, 23 patients) was characterized by exceptionally high costs incurred by comorbidities.

The majority of RA patients had favourable outcomes and low costs. However, a large group of patients was distinguished by chronic pain, disability, and fatigue not unambiguously linked to disease activity. The highest healthcare costs were linked to high disease activity or comorbidities.