Background/Purpose: Treatments for ankylosing spondylitis (AS) have been shown to improve patient-reported outcome (PRO) measures in clinical studies; however, healthcare decision makers have limited ability to translate these improvements to healthcare resource utilization (HCRU) or cost savings. Few studies have assessed the economic impact of functional status and patient-reported disease burden in US patients with AS. The purpose of this study was to evaluate the association of PRO measures with HCRU and medical costs in patients with AS from a national US registry.

Methods: FORWARD is a longitudinal observational databank for rheumatic diseases that collects patient-reported data through questionnaires administered every 6 months. Data collected include demographics, clinical characteristics, symptoms, health and functional status, health-related quality of life, and HCRU. This cohort study included adult participants with a diagnosis of AS enrolled in FORWARD between July 2009 and June 2019 who completed ≥ 1 questionnaire between January 2010 and December 2019 and had completed the Health Assessment Questionnaire Disability Index (HAQ-DI) and/or Bath Ankylosing Spondylitis Disease Activity Index (BASDAI; added in 2018). Patient demographics, clinical characteristics, and PRO data were collected from the most recent questionnaire. HCRU and medical costs (USD 2019) for all hospitalizations, emergency department (ED) visits, outpatient visits, diagnostic tests, and procedures were assessed for the 6 months prior to survey completion. The relationships between HAQ-DI or BASDAI and HCRU and cost outcomes were assessed using negative binomial regression models for HCRU outcomes and generalized linear models with gamma distribution and log-link function for cost outcomes adjusted for confounders.

Results: A total of 334 patients with AS who completed the HAQ-DI and/or BASDAI questionnaires were included. The mean (SD) age and disease duration were 54.4 (14.3) and 17.5 (12.4) years, respectively. Overall, 61.7% of patients were female and 94.6% were white. The mean (SD) HAQ-DI and BASDAI at time of patients’ most recent survey were 0.9 (0.7) and 3.7 (2.3), respectively (Table 1). HAQ-DI was positively associated with number of hospitalizations, ED visits, outpatient visits, diagnostic tests, and procedures, whereas BASDAI was not associated with HCRU outcomes (Figure 1). Overall mean (SD) direct medical costs for patients with AS were $6520.50 ($12,732.90). There was a significant positive association (coefficient [95% CI]) between medical costs and HAQ-DI (1.76 [1.22-2.55]; P < 0.01), but not with BASDAI (1.05 [0.91-1.22]). Adjusted average medical costs increased with increasing HAQ-DI and BASDAI scores (Figure 2).

Conclusion: Higher HAQ-DI scores were associated with greater HCRU and higher medical costs among patients with AS included in FORWARD, but BASDAI scores were not. These findings indicate that greater functional impairment may impose an increased economic burden compared with other patient-reported aspects of AS throughout the course of the disease. Therapies that effectively improve functional impairment may reduce costs for patients and the healthcare system.

« Back to ACR Convergence 2020

ACR Meeting Abstracts - https://acrabstracts.org/abstract/association-of-healthcare-utilization-and-costs-with-patient-reported-outcomes-in-patients-with-ankylosing-spondylitis/