Objective: To evaluate: (i) a correct equivalence ratio of clinical efficacy between low-dose deflazacort (DFZ) and methyl prednisolone (MP); and (ii) bone metabolic effects of low-dose DFZ and MP in the treatment of male RA and PsA.
Methods: A total of 21 male patients with active RA or PsA, naive to steroid treatment were chosen for the study. Group I: 10 patients treated for 6 months with DFZ 7.5 mg, calcium, cholecalciferol and a DMARD; for the following 6 months with MP 4 mg, calcium, cholecalciferol and a DMARD. Group II: 11 patients treated for 6 months with MP 4 mg, calcium, cholecalciferol and a DMARD; for the following 6 months with DFZ 7.5 mg, calcium, cholecalciferol and a DMARD. At day 0, 90, 180, 240 and 360 evaluation of ACR improvement criteria; a blood sample for total and bone-specific ALP, calcium, phosphorus, PTH, SHBG, estradiol, ACTH, osteocalcin, LH, OPG; a sample of urine for calcium, phosphorus, creatinine and DPD.
Results: 13/21 patients (6/10 Group I; 7/11 Group II) reached ACR 20 at 6 months; 14/21 (7/10 Group I, 7/10 Group II) at 12 months. Only at the third month we observed in Group II vs Group I a reduction of OPG (24% vs 6%, P = n.s.); ALP (P < 0.001) and osteocalcin (P = 0.006) decreased in both groups from the third month; DPD decreased in both groups only from the sixth month (P = 0.002).
Conclusions: The correct equivalence ratio of DFZ to MP is 1.875:1, and of DFZ to prednisolone 1.5:1. We found a relative prevalence of bone resorption compared to bone formation in the first 6 months of treatment. The trend of OPG requires further investigation.