Functional outcome of myositis patients: can a low-dose glucocorticoid regimen achieve good functional results?

During the last few years, in an attempt to reduce the side effects of glucocorticoid (GC) therapy, we have been treating polymyositis-dermatomyositis (PM-DM) patients with a lower starting dose of GC than is classically recommended. In order to validate this approach, we performed a functional re-evaluation of these PM-DM patients.

A comprehensive protocol evaluating muscle strength, muscle function, CK levels, persistence of spontaneous activity on electromyography, disability in daily life activities and degree of dependence was applied in 25 non-cancer-associated biopsy-proven PM-DM patients, 15 of whom had been treated with a high-dose regimen (i.e. > 0.5 mg prednisolone/kg/day) and 10 with a low-dose regimen (i.e. < or = 0.5 mg prednisolone/kg/day).

Our results indicate that the functional outcome of PM-DM patients given a low-dose starting regimen of GC does not differ from that observed in patients given higher doses. Interestingly, vertebral fractures were less common in patients treated with lower GC doses.

Although our analysis has certain shortcomings, including the small number of patients investigated and their uncontrolled assignment to a low-dose or a high-dose GC regimen, the results of this retrospective study suggest that a low-dose starting regimen of GC can achieve a good functional outcome in PM-DM patients, with a reduction of treatment-related disability. This approach would be welcome as a step forward should it be validated by a longitudinal study.