Knee osteoarthritis heightens mortality risk

Knee osteoarthritis (OA), whether symptomatic or radiographic, contributes to an increased risk of all-cause mortality, with the risk increase from symptomatic knee OA partially attributed to its effect on disability and quality of life (QoL).

The study used data from the Osteoarthritis Initiative and included 1,387 participants with symptomatic knee OA (ie, both radiographic knee OA [Kellgren and Lawrence grade ≥2]) and knee pain), 856 with knee pain only, 1,117 with radiographic knee OA only, and 1,139 with neither radiographic knee OA nor knee pain.

Compared with those who had neither radiographic knee OA nor knee pain, participants with symptomatic knee OA were more likely to have higher body mass index and disability score, more comorbidities, depressive symptoms, widespread pain, knee injury history, and oral pain medications use. They also had lower physical (PCS) and mental component summary scores (MCS) of QoL.

Over a follow-up of 96 months, 282 participants died. In multivariable Cox‐proportional models, the risk of all-cause mortality was higher in participants with symptomatic knee OA (hazard ratio [HR], 2.2, 95 percent confidence interval [CI], 1.6–3.1), with knee pain only (HR, 0.9, 95 percent CI, 0.6–1.4) or with radiographic knee OA only (HR, 2.0, 95 percent CI, 1.4–2.9) relative to those with neither radiographic knee OA nor knee pain.

Symptomatic knee OA exerted an indirect effect on mortality via PCS of QoL (HR, 1.2, 95 percent CI, 1.0–1.4; percentage of mediation, 26.5 percent) and disability (HR, 1.1, 95 percent CI, 1.0–1.4; percentage of mediation, 22.4 percent). There was no apparent mediation effect seen via either MCS of QoL or the use of oral pain relief medications.

The present data highlight the importance of developing appropriate preventive and treatment strategies to reduce the risk of knee OA, as well as interventions focused on improving function and QoL to reduce all-cause mortality among patients with symptomatic knee OA, according to researchers.