Statin use may reduce the progression of osteoarthritis of the knee, although not of the hip, a prospective Dutch study suggested.

During approximately 6.5 years of follow-up, the adjusted odds ratio for progression of knee osteoarthritis was 0.43 (95% CI 0.25 to 0.77, P=0.01) among study participants who took statins, according to Bruno H. Ch. Stricker, MD, of Erasmus Medical Center in Rotterdam, and colleagues.

In contrast, statin use did nothing to prevent worsening of osteoarthritis of the hip (OR 1.10, 95% CI 0.63 to 1.90, P=0.74), the researchers reported in the May Annals of the Rheumatic Diseases.

“The difference in effect on hip joints in the present study may indicate a difference in pathogenesis between the knee and the hip,” they observed.

Unlike for rheumatoid arthritis, there currently are no disease-modifying medications for osteoarthritis.

To see if targeting articular and systemic inflammation - both of which are affected by statins - could provide disease-modifying effects in osteoarthritis, Stricker and colleagues analyzed data from 2,921 participants in the Rotterdam cohort study.

More than half were women, mean age was 65, and 10.9% began taking statins during the study.

To be considered statin users, they had to take the drugs for at least 4 months and at least half the recommended daily dose.

At baseline, radiographic evidence of osteoarthritis was present in 677 knees and 335 hips.

These numbers increased to 939 knees and 508 hips at the conclusion of the study.

The reduction in overall progression with statin use was seen after adjustment for multiple factors, including baseline radiographic scores, age, sex, body mass index, smoking, femoral bone mineral density, arterial hypertension, and diabetes.

Among participants with knee osteoarthritis, a lower likelihood of progression was associated with increasing length of statin use:

Less than 4 months, OR 1.77 (95% CI 0.71 to 4.44, P=0.22)
4 to 12 months, OR 0.30 (95% CI 0.08 to 1.19, P=0.09)
More than 1 year, OR 0.49 (95% CI 0.26 to 0.92, P=0.03)
Progression of hip osteoarthritis was not influenced by duration of statin treatment.

“Our data suggest that osteoarthritis of the knee is influenced more by metabolic factors such as the secretion of cytokines and adipokines by adipose tissue, vascular pathology in the subchondral bone, or the direct effects of lipids on joint tissues than osteoarthritis of the hip,” Stricker and colleagues observed.

A potential limitation of the study was its observational design, which allowed for possible selection bias.

In addition, the researchers did not consider the effects of statins on pain and disability.

Nonetheless, they called for further studies of statins in these patients because of the demonstrated metabolic and articular effects.

The need for assessment of symptomatic effects before statins can be recommended for osteoarthritis disease modification was echoed in an accompanying editorial by Philip G. Conaghan, MD, PhD, of the University of Leeds in England.

“Concomitant symptom relief remains an important component of regulatory acceptance of an [osteoarthritis] structure modifying therapy,” he stated.

“However, the growing science supporting this intriguing field together with the parallel growth of research that leads to a ‘systems’ biological approach to the [osteoarthritis] joint organ (where cartilage, subchondral bone, inflammation, vascularity and biomechanics are all considered, made feasible with modern imaging) has incredible implications for broadening [osteoarthritis] research and tissue targets,” Conaghan wrote.

Primary source: Annals of the Rheumatic Diseases
Source reference: Clockaerts S, et al “Statin use is associated with reduced incidence and progression of knee osteoarthritis in the Rotterdam study” Ann Rheum Dis 2012; 71: 642-647.

Additional source: Annals of the Rheumatic Diseases
Source reference: Conaghan P “The effects of statins on osteoarthritis structural progression: another glimpse of the Holy Grail?” Ann Rheum Dis 2012; 71: 633-634.