Osteoarthritis Predicts Persistent Knee Pain in Women Over 50

Based on a 12-year longitudinal study, researchers have found that 63% of women over 50 report persistent, incident, or intermittent knee pain. Factors associated with persistent pain included elevated body mass index (BMI), prior damage to the knee, and radiographic osteoarthritis (OA).

The researchers acquired data from a prospective population-based study of OA and osteoporosis established in 1989, known as the Chingford Study. The study involved over 1,000 women between the ages of 44 and 57, with a median age of 52. The researchers assessed data from the study involving self-reported knee pain to classify 489 participants into four separate pain groups: asymptomatic, persistent, incident, and intermittent.

The researchers found that 44% of the participants reported having “any days of pain” and 23% reporting having “pain on most days of the previous month.” Of the participants experiencing “any days of pain,” 9% were classified as having persistent pain, 24% as having incident pain, and 29% as having intermittent pain. By comparison, only 2% of those who reported “pain on most days” were classified as having persistent pain, while 16% were classified as having incident pain and 18% as having intermittent pain.

Women with an elevated BMI were associated with persistent and incident pain patterns, while women with radiographic OA were connected to persistent pain. Participants who reported a prior knee injury were more likely to suffer from persistent or intermittent pain.

The American College of Rheumatology estimates that 27 million Americans over the age 25 suffer from OA. Patients with OA commonly experience intense pain in certain joints, such as the knee, but treatment is often expensive. In 2004, nearly 500,000 complete knee replacement procedures were conducted in the US, costing over $14 billion according to the Centers for Disease Control and Prevention.

“Understanding the prevalence and predictors of knee pain is the first step in developing comprehensive pain assessment plans that could lead to more targeted treatment options for those burdened by OA,” said lead study author Nigel Arden, MD, professor of rheumatology at the University of Oxford in the UK, in a press release.

This study was published online earlier this month by Arthritis & Rheumatism.