Background: The aetiology of bone loss in inflammatory bowel disease is multifactorial, but oral corticosteroids are an important contributory factor. Rectally administered steroids are widely used in patients with distal disease, but very little is known about their effect on bone metabolism. The aim of this study was to investigate the effect of a standard course of rectal prednisolone on biochemical markers of bone turnover.
Methods: In a longitudinal study of 10 patients, biochemical markers of bone turnover were measured before, during and after treatment with prednisolone metasulphobenzoate (Predfoam, Pharmax Ltd) 20 mg twice daily for 2 weeks. Bone formation markers measured were serum osteocalcin (BGP), bone-specific alkaline phosphatase (BALP) and procollagen carboxy-terminal propeptide (PICP). Urinary deoxypyridinoline (dPyr) was measured to assess bone resorption.
Results: Disease activity scores improved during treatment (difference in mean Powell-Tuck score = 2.3 (+/-13.1), 95% CI: 0.11-4.48, P = 0.04). There was a significant fall in BALP (P = 0.02) during treatment, and a rapid but non-significant fall in BGP (P = 0.19). PICP (0.42), and urinary dPyr (0.30) did not change significantly during treatment.
Conclusions: Following a standard 2-week course of rectal prednisolone metasulphobenzoate, we observed a significant fall in bone-specific alkaline phosphatase activity. These results suggest that bone formation is suppressed in patients with distal colitis treated with pharmacological doses of rectal steroids.