Smartphone Apps Can Help Track Disease Activity in Rheumatoid Arthritis

Technological advances are transforming the practice of medicine in numerous ways.  For example, telemedicine facilitates the provision of specialty care for patients with limited access. This is especially true for specialties that have a shortage of physicians, including rheumatology.¹ Other electronic tools can also be used between visits to benefit both rheumatologists and their patients.

Rheumatoid arthritis (RA) is one condition for which smartphone apps have the potential to improve medical care, patient satisfaction, and the scope of research on the disease. These tools “can allow for tracking of disease activity and flares over time, and in a way, they can educate patients about their disease and how to follow it,” said Alexis R. Ogdie-Beatty, MD, MSCE, a rheumatologist and assistant professor of medicine at the Hospital of the University of Pennsylvania. “They can also provide physicians with a range of information that quantifies the patient’s disease activity and functional ability since the last visit, and they allow for research into flares, disease activity, and which interventions may be helpful or harmful,” she told Rheumatology Advisor.

Several recent studies have examined the use of such apps to monitor RA disease activity, which can often fluctuate between healthcare provider visits. Research published in November 2016 compared the congruence between responses to a questionnaire administered both in a digital app format and in a paper-and-pencil version.² The questionnaire included 3 visual rating scales: Visual Analog Scale, Global Health score, and Patient Global Assessment of Disease Activity. A total of 185 adult patients with RA were randomly assigned to complete the questionnaire in one format first and then in the other format. The results show excellent intra-rater agreement between the 2 formats for all 3 scales (intraclass correlation coefficient >0.75, P< .001).

In a study reported in 2014, researchers at Kyoto University Graduate School of Medicine investigated the association between 28-joint disease activity scores (DAS28) measured during physician visits and scores from a self-assessment smartphone app in 65 patients with RA.³ The self-assessment tool included the modified Health Assessment Questionnaire (mHAQ), as well as tender joint and swollen joint counts; it also measured patients’ trunk acceleration with the autocorrelation (AC) peak calculated as one of the gait parameters. 

The findings reveal a significant association between the DAS28 and mHAQ (β = 0.264, P <.05), tender joint counts (β = 0.581, P <.001), and AC (β = -0.157, P <.05), suggesting that “noninvasive self-assessment of a combination of joint symptoms, limitations of daily activities, and walking ability can adequately predict disease activity of RA with a smartphone application,” the authors concluded.

In a 2016 study, the same group of researchers expanded on their earlier findings by comparing patient-assessed disease activity with that measured by physicians.⁴ Each day for a period of 3 months, patients used a smartphone app based on a DAS28 predictive model, and once a month during clinical visits, a rheumatologist measured patients’ DAS28 based on C-reactive protein levels. 

The disease activity assessed by the app was shown to correlate well with the disease activity as measured by rheumatologists, and the majority of patients indicated that the app was useful and user-friendly. A recent review by rheumatologists from multiple international universities found similar results from several additional studies, and the authors highlighted various apps that are currently being used or developed for use by patients with inflammatory arthritis.⁵