Knee osteoarthritis linked to premature mortality

Knee osteoarthritis was independently associated with increased risk of premature mortality in the largest-ever meta-analysis to examine the issue, as reported at the World Congress on Osteoarthritis.

The meta-analysis used individual patient-level data on 11,954 participants in six prospective observational cohort studies conducted in four countries. The key finding: Subject with symptomatic  and radiographically confirmed knee OA were at 17 percent greater risk of premature mortality, compared with pain-free, radiographically negative participants, independent of age, sex, and race, according to a musculoskeletal epidemiologist at the University of Oxford (England).

Prior studies have reported conflicting results regarding the impact of lower-limb OA on mortality. That’s because those studies have used different definitions of OA and in some cases didn’t adjust for potential confounding factors. For this new meta-analysis, investigators harmonized individual patient data to overcome those limitations through the use of consistent definitions and statistical methods, she explained at the congress, which was sponsored by the Osteoarthritis Research Society International.

The six prospective cohort studies included in the new analysis are well known in the field of osteoarthritis research: the Framingham (Mass.) Osteoarthritis Study, the Rotterdam (the Netherlands) Study, the Multicenter Osteoarthritis Study (MOST), the Johnston County (N.C.) Osteoarthritis Project, the Tasmanian Older Adult Cohort Study, and the Chingford (England) 1000 Women Study. These studies feature 7.4-23.7 years of prospective follow-up.

In an interview, it was said that the current analysis uses all-cause mortality as the outcome because causes of death are recorded differently in the countries where the studies are taking place. It will take several more years for statisticians to harmonize the cause-of-death data and draw definitive conclusions; however, preliminary analysis suggests the causes of premature mortality in the knee OA patients are disproportionately cardiovascular.