Impact of low-dose prednisolone on bone synthesis and resorption in early rheumatoid arthritis: experiences from a two-year randomized study

Patients with rheumatoid arthritis (RA) have an increased frequency of osteoporosis, mainly because of increased bone resorption. Reduction of disease activity is suggested to reduce bone remodelling. It might also be possible that prednisolone treatment could cause this effect because prednisolone has been shown to arrest the development of joint destruction in early RA. Therefore, we examined the effects of low-dose prednisolone on serum concentrations of bone remodelling markers and insulin-like growth factor-1 (IGF-1) in RA patients in relation to bone mineral density.

One hundred and fifty patients, 67% women, with early RA, mean disease duration of six months (95% confidence interval (CI) = three to eight months), who had participated in the BARFOT (Better Anti-Rheumatic FarmacOTherapy) low-dose prednisolone study were included. They had been randomised to either the P-group, who were treated with 7.5 mg prednisolone daily (n = 70, mean age = 51 years, 95% CI 48 to 54 years), or the NoP-group, who received no prednisolone (n = 80, mean age 58 years, 95% CI 56 to 61 years), when they started their first disease-modifying anti-rheumatic drug (DMARD). Serum samples were analysed at baseline, 3 and 12 months for procollagen type I N-terminal propeptide (P1NP), a marker of bone formation, and the C-telopeptide crosslaps of type I collagen (CTX-1) and C-terminal telopeptide of type I collagen (1CTP), markers of bone degradation. IGF-1 was analysed at baseline and after 12 months. Bone mineral density at the lumbar spine and femoral neck was assessed by dual-energy X-ray absorptiometry at baseline and after 24 months.

Levels of P1NP decreased rapidly in the P-group (p < 0.001). Levels of CTX-1 and 1CTP decreased in both treatment groups, but significantly more in the P-group (differences between groups p < 0.019 and p < 0.001, respectively). IGF-1 increased in the P-group (p < 0.001) but remained stable in the NoP-group. Bone mineral density decreased in the spine in both groups, significantly more in postmenopausal women from the P-group. Femur bone mineral density only decreased in the NoP-group.

Low-dose prednisolone in early RA counteracts the negative impact of rheumatoid inflammation on bone tissue in the hip, a juxta-articular localisation. Thus bone mineral density was preserved in the femur in the P-group and 1CTP decreased rapidly. However, the systemic inflammatory consequences on bone could not be prevented in the lumbar spine, especially not in postmenopausal women, probably because of the combined effect of suppression of bone synthesis by prednisolone and the postmenopausal status.