Background Polymyalgia rheumatica (PM) is a common inflammatory disease that affects elderly patients in Western countries, and is usually treated using glucocorticoid (GC) therapy that still play the major role in the treatment of the disease by rapidly recunding and suppressing inflammation within a few week. The circadian administration of prednisone in rheumatoid arthritis showed that optimizing the timing of GC administration with low-dose modified-release prednisone (MR-P)improves the benefit ratio of long-term GC treatment (CAPRA 1-2 studies).

Objectives To compare changes in inflammation markers and their correlations with cortisol levels in PM patients treated with the new MR-P tablet or 6-methylprednisolone (6-MP).

Methods The 42 enrolled patients fulfilled the 2012 EULAR/ACR criteria for PM: 17 were treated with 6-MP 12 mg at 8.00 a.m. then gradually tapered to 2 mg/daily (group A: 10 females; mean age 72.5 years), and 25 were treated with MR-P10 mg at 10.00 p.m, tapered to 1 mg (group B: 14 females; mean age 74.6 years). Their erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), fibrinogen, cortisol levels, cytokine (TNF-α and IL6)were measured at baseline and after six months. Circulating cytokine levels were determined using Human IL-6 Instant ELISA Bioscience, Bender, MedSystems, GmbH (Vienna, Austria) and Human TNFa Quantikine immunoassay RD System INC.(Minneapolis, USA).

Results The baseline laboratory parameters in group A and B were respectively: ESR 30.6±18.2 vs33.3±17.6 mm/h (p=n.s.); CRP 1.5±1.8 vs2.5±3.6 mg/dL (p=n.s.); fibrinogen 456±161 vs482±160 mg/dL (p=n.s.); cortisol 16.1±7.2 vs11.2±6.2 μg/dL (p=n.s.) and TNF-α1.0±0.6 vs1.2±0.7 pg/mL (p=n.s.). Baseline IL6 values were lower in group A 1.7±1.1 vs4.5±5.0 pg/mL in group B, p<0.01) and abnormal IL6 values at baseline were in eight (47%) group A vs twenty(84%) group B patients (p<0.05).

After the first month oftreatment, the decrease in IL-6 levels in group A and B were respectively 50% and 85.7% (p <0.001).

After six months of treatment, the same parameters were: ESR 18.2±15.6 vs20.5±16.5 mm/h (p=n.s.); CRP 0.7±0.6 vs0.6±0.8 mg/dL (p=n.s.); fibrinogen 441±101 vs372±85 mg/dL (p=n.s.); cortisol 14.1±5.4 vs11,7±4.8 μg/dL (p=n.s.); TNF-α2.9±7.2 vs3.6±11.4 pg/mL (p=n.s.); and IL-6 1.2±0.5 vs1.6±1.4 pg/mL (p=n.s.).

After six months of treatment, there wasn’t a statistically significant difference in the GC dose between group A and group B (3.9±1.8 mg vs3.5±1.8 mg).

Conclusions In this non-randomized prospective observational study the response of inflammation markers to low-dose GC was similar in patients with PM treated with 6-MP or MR-P, and morning cortisol levels were unaffected. However, the patients treated with MR-P showed a greater decrease in IL-6 levels after the first month.

Disclosure of Interest None Declared