Strontium ranelate effect in postmenopausal women with different clinical levels of osteoarthritis

The objective of this post hoc analysis was to investigate the effect of strontium ranelate on a cartilage degradation marker in postmenopausal women who participated in a randomized, placebo-controlled osteoporosis study. Women were stratified according to reported symptoms of osteoarthritis and to the baseline levels of a cartilage degradation marker.

The analysis included the 2617 postmenopausal women (75 years old) with osteoporosis randomized to strontium ranelate or placebo for a 36-month period. Cartilage degradation was evaluated using a validated urinary marker adjusted for creatinine (CTX-II/cr), whereas bone resorption was assessed by serum CTX-I. The presence of osteoarthritis was determined by individual interviews.

CTX-II was significantly elevated at baseline in subjects with a history of osteoarthritis (OA+) compared to subjects who did not (OA-) (p < 0.0001), whereas CTX-I was unaffected by osteoarthritis status. Strontium ranelate caused a significant decrease from baseline in CTX-II over a 12-month period whatever the osteoarthritis status. Strontium ranelate-treated patients had a significant decrease in CTX-II compared to placebo in both OA+ and OA- groups up to 12 months, the difference remaining still significant at 36 months in patients from the OA- group (p < 0.001).

The CTX-II profile of changes over 3 years may reflect efficacy of strontium ranelate against cartilage degradation, with an enhanced beneficial effect in subjects with early or mild clinical osteoarthritis, probably exerting its putative chondroprotective influence in early stages of the disease. Carefully controlled studies in targeted populations with early osteoarthritis are warranted to assess the role of strontium ranelate halting osteoarthritis progression.