Presence of Multimorbidities Negatively Impacts Rheumatoid Arthritis Treatment

Patients suffering from rheumatoid arthritis (RA) frequently have comorbidities such as depression, asthma, cardiovascular events (including myocardial infarction and stroke), solid malignancies, and chronic obstructive pulmonary disease, among others.

When the additional conditions are identified—which, of course, is not always the case—diagnosing and treating comorbidities can involve coordination of care among several specialties. Adding to this challenge, as noted in a recent study in Rheumatology, is the possibility that the presence of multimorbidities can significantly reduce remission and low disease activity (LDA) for RA patients.The study is among the first to look at the effectiveness of RA treatment with disease-modifying anti-rheumatic drugs (DMARDs) when multimorbidities are present.

In a prospective RA cohort, the study authors identified 815 patients taking DMARDs and examined follow-up data after 1 year of treatment. Treatment effects were measured using the clinical disease activity index (CDAI) and the modified health assessment questionnaire (MHAQ). The presence of multimorbidity was assessed using a counted multimorbidity index (cMMI). Then, the study authors used regression models to calculate the odds ratio of achieving remission or LDA and predicted the CDAI and MHAQ one year after DMARD commencement, adjusting for age, sex, disease duration, disease activity when DMARD treatment began, type of DMARD, and use of other treatments, including steroids and non-steroidal anti-inflammatory drugs.

Patients taking DMARDs typically experience symptom relief within 4 to 6 weeks (although time to effect is typically shorter for biologic DMARDs), although other studies have shown that longer duration of therapy may significantly enhance the benefit of medication therapy. But for the study patients suffering from multimorbidities, more than half of all patients who started DMARD therapy were on the same medication after 1 year. The connection between multimorbidity and failure to reach remission or LDA after 1 year was significantly lower in patients with a high cMMI score.

The study authors note, “After accounting for covariates, the odds ratio for remission associated with each additional morbidity in the cMMI was 0.72 (95% CI 0.55, 0.97) and 0.81 (95% CI 0.70, 0.94) for LDA. One year after DMARD initiation, CDAI (+0.16 per additional morbidity) and MHAQ scores (+0.15 per additional morbidity) were significantly worse (both P< .05).

The study results serve as a strong reminder for rheumatologists treating RA patients to examine patients for comorbidities and multimorbidities. If the study results are further validated, they may also point to a necessary discussion point with RA patients on treatment effectiveness and expected time to remission.