Steroids were continued for a median of 18 months (range 10.8–128.7). The combination of steroids and a second-line agent was
used in 49% (28/57) of patients at diagnosis and 79% (45/57) during the course of their illness. Sixty-three percent of patients (36/57) were treated with methotrexate (MTX) at some point in the illness and of these, 75% were commenced at diagnosis. Only 14% (4/29) of patients diagnosed prior to 2000 were managed with disease-modifying anti-rheumatic drugs (DMARDs) at diagnosis compared with 86% (24/28) of those managed after 2000 (Fig. 3). Disease course was determined in 45 (79%) patients. The remaining 12 patients had less than 36 months follow-up. The disease was monophasic in 46.7% (21/45),
Etoposide in vitro polyphasic in 17.7% (8/45) and chronic in 35.5% (16/45). For monophasic, polyphasic and chronic course, the median time to first remission was 15.7, 22 and 57.7 months, respectively. For Venetoclax the entire cohort, the median time to first remission was 22.3 months. Nine patients relapsed following a period of remission, eight with polyphasic disease and one with chronic disease. The median time to relapse for patients with polyphasic disease was 11 months (range: 8.0–20.8). Our cohort demonstrates similar epidemiological and clinical characteristics to those reported from centres in North America, South America, Japan and Europe.[1, 2, 4, 9-14] We have confirmed that female predominance, pre-pubertal
onset and a significant duration of symptoms prior to diagnosis, are common epidemiological features of this 3-mercaptopyruvate sulfurtransferase disease. We have also shown that there are a broad range of clinical features in addition to skin rash and muscle weakness which comprise the clinical syndrome of JDM. Not unexpectedly the most frequently observed clinical features at diagnosis were weakness and typical rash. Also common were myalgia, arthralgia and nailfold changes. The frequencies of these features are comparable to other studies.[1, 2, 9-11, 13-15] Calcinosis was not seen in any of our patients at diagnosis and was observed in only 18% of cases throughout the disease course. This is lower than reported rates at other centres where rates of calcinosis of up to 40% have been reported.[9-12, 14, 16, 17] The reason for the lower rates of calcinosis in the present study is unclear. It has been postulated that a longer duration of symptoms prior to diagnosis increases the risk of developing calcinosis. However, the time to diagnosis in our cohort was similar to those in papers reporting higher rates of this complication. It is possible that the lower rates of calcinosis in our cohort reflect the more aggressive approach to treatment in recent years. Muscle enzymes have been reported in the literature to be abnormal in up to 90% of patients with JDM; however, individual enzymes appear to be abnormal at lower rates.