Data published in Arthritis Research and Therapy suggest that mixed connective tissue disease is a relatively stable disease with infrequent periods of long-term remission.
“Consensus on the stability of [mixed connective tissue disease (MCTD)] would affect future research and the management of patients,” Silje Reiseter, MD, of the University of Oslo, in Norway, and colleagues wrote. “Several previous studies have assessed morbidity and mortality risk factors and prognosis in cohorts where, at a defined time point, patients fulfilled one or more of the criteria sets for MCTD. Ultimately, when clinicians assess an individual patient, the key question is: Does the patient belong to a specific risk group?”
To determine how and whether MCTD can evolve into another rheumatic disease, as well as the persistence of remission following long-term observation, the researchers conducted a large, population-based, prospective, observational study with 118 participants. MCTD was determined to have evolved through the development of new auto-antibodies and symptoms consistent with another condition.
Reiseter and colleagues defined remission as a systemic lupus erythematosus disease activity index 2000 (SLEDAI-2 K) of 0, and European League Against Rheumatism scleroderma trials and research (EUSTAR) activity index of less than 2.5.
According to the researchers, 12% of participants developed another rheumatic disease from MCTD following a mean duration of 17 years (SD = 9). They also found that “puffy hands” was a predictor of a stable MCTD phenotype (OR = 7; 95% CI, 2-27). MCTD activity decreased gradually, according to SLEDAI-2 K scores. Further, more than 90% of participants had an EUSTAR activity index of less than 2.5. However, just 13% of patients achieved remission throughout the entire mean observation period of 7 years (SD = 2). Percentage of predicted high forced vital capacity proved to be the strongest predictor of remission.
The researchers added that MCTD’s low SLEDAI-2 K and EUSTAR scores suggest that it may be a milder disease than systemic lupus erythematosus and systemic sclerosis.
“Phenotype stability in MCTD has been an ongoing debate for many years, but has rarely been addressed by large, population-based longitudinal studies,” Reiseter and colleagues wrote. “The results of this study indicate that the majority of patients with MCTD retain their phenotype during long-term observation and MCTD involves milder disease activity than [systemic sclerosis] and [systemic lupus erythematosus].” – by Jason Laday
Disclosure: The researchers report no relevant financial disclosures.