Study Finds That Disability in RA Begins 1 to 2 Years Before Diagnosis

Functional disabilities (FD) start to appear in patients with rheumatoid arthritis (RA) 1 to 2 years before diagnosis, signaling that earlier diagnosis and more aggressive treatment may lessen the burden of disease, according to a study released today.

The study, published in Mayo Clinic Proceedings, is the first to quantify the long-term trends in prevalence of FD in RA.

The study examined patient-reported FD in RA versus in individuals without RA within 3 years before RA incidence/index date and over RA disease duration, age, sex, and calendar time. It also defined the effect of rheumatoid factor/anti-cyclic citrullinated peptide—positivity (RF/CCP-positivity) on the prevalence of FD in patients with RA.

Researchers used information from the Rochester Epidemiology Project database of medical records, and examined questionnaires about activities of daily living from 586 patients with RA and 531 people without.

The RA incidence date was defined as the earliest date of fulfillment of 4 or more of the 1987 American Rheumatism Association RA criteria. The index date for each individual without RA corresponded to the incidence date of the patient with RA.

Activities of daily living (ADL) were part of the self-report questionnaire given annually to all Mayo Clinic patients during routine outpatient appointments; the completion of the questionnaires was independent of rheumatologic care. The questionnaires asked about the ability to perform 6 ADLs without assistance, including feeding oneself, dressing, using the toilet, bathing, walking, and housekeeping. FD was defined as having difficulty with either 1 or more or 2 or more of the 6 ADL.

The prevalence of FD was more than twice as high in those with RA (26%) as those without (11%) at the RA incidence/index date (P <.001), with persistent excess over the follow-up and calendar time. Patients with RA had a 15% or higher prevalence of FD than individuals without RA in most age groups.

In the period from 3 to 2 years before RA incidence/index date, there was no statistically significant difference between the 2 groups. But from 2 years to 1 year before and within 1 year before RA incidence/index date, patients with RA had a significantly higher prevalence of FD than the non-RA group (odds ratio [OR] 2.07; 95% CI, 1.66-3.64; P = .014 and OR, 2.78; 95% CI, 1.63-4.72; P <.001, respectively).

"This is a new finding and a finding that is quite intriguing," Elena Myasoedova, MD, PhD, a Mayo Clinic rheumatologist and the study's primary author, said in a statement. "It may reflect an accumulation of symptoms between the time of first onset and the time required for providers to actually diagnose patients."

Also noteworthy is the finding that the persistent excess in FD continued even after diagnosis and treatment, she added, which may be due to a growing burden of mental and physical pain, use of glucocorticoids and antidepressants, increasing expectations for relief from symptoms, and other factors.

In addition, the prevalence of FD was higher in women than in men in both RA (P <.001) and non-RA groups (P = .04).

The prevalence of FD overall was similar in RF/CCP-positive vs RF/CCP-negative patients with RA (P = .67). However, there was a significant interaction between RF/ CCP positivity and disease duration (P = .03), reflecting an increase in prevalence of FD over disease duration in patients with RF/CCP and a decline in FD prevalence in those without RF/CCP. For FD defined as difficulty with 2 or more ADLs, the results were similar.

Reference

Myasoedova E, Davis JM, Achenbach SJ, Matteson EL, Crowson CS. Trends in prevalence of functional disability in rheumatoid arthritis compared with the general population [published online April 30, 2019]. Mayo Clin Proc. doi: 10.1016/j.mayocp.2019.01.002.