Effect of early treatment in polymyositis and dermatomyositis


Abstract: Aim: To compare the effect of early and late onset of treatment in patients with polymyositis (PM) and dermatomyositis (DM). Methods: In a cohort study, all adult patients with definite diagnosis of PM or DM treated for at least 12 months were included. They were divided into two groups according to the time of treatment onset: Early (within 3 three months) and Late (after 3 three months). The number of patients with positive therapeutic response (going to remission in less than one year) and the mean time elapsed for reaching the remission were assessed and compared between the two groups. Chi-square test, Fisher's exact test, t-test and Pearson correlation test were used for data analysis. Results: Sixty-five patients were included, 42 with DM and 23 with PM. Late group included 24 patients (7 seven PM and 17 DM), while Early group included 41 patients (16 PM and 25 DM). Positive therapeutic response rate was higher in Early group (80 vsvs. 46 percent%, pP:0.004). The mean time needed to go to remission was much less with early treatment (5.5 vsvs. 11.9 months, pP:0.003). The relapse rate was also lower in Early group (5 vsvs. 25 percent%, pP<0.02). The comparison of treatment outcome showed the same results in both PM and DM, but it was statistically significant only in those with DM. Conclusions: Considering the above results, we may conclude that early treatment in patients with PM and DM has a better therapeutic outcome, shortens treatment period and reduces complications. Key words: Dermatomyositis, early treatment, inflammatory myositis, polymyositis, relapses.