Inadequate pain relief common among patients with knee osteoarthritis

Inadequate pain relief is common among patients with knee osteoarthritis (OA), with more than half of patients having persistent pain, a study found.

Researchers conducted a prospective, noninterventional study in patients age 50 years and older with physician-diagnosed knee OA from 53 centers in 6 European countries. Merck Sharp & Dohme funded and participated in the study. Patients had taken pain medication for at least 14 days. Pain and function were assessed using the Brief Pain Inventory (BPI) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Inadequate pain relief was defined as an average pain score of >4 out of 10 on BPI question 5. Quality of life was assessed using a 12-item short form.

Results appeared in the February Rheumatology.

Of 1,187 patients enrolled, 639 (54%; 95% CI, 51% to 57%) reported inadequate pain relief as measured on the BPI average pain score. Patient responses for the BPI average pain question were well correlated with responses on the WOMAC pain subscale. Patients with inadequate pain relief had greater odds of being female (adjusted odds ratio [OR], 1.90; 95% CI, 1.46 to 2.48) and having OA in both knees (OR, 1.48; 95% CI 1.15 to 1.90), as well as higher body mass index, longer OA duration, depression, and diabetes. Patients with inadequate pain relief were more likely to have worse quality of life, greater function loss, and greater pain interference.

The authors noted that the analgesic medications patients most commonly reported using were nonsteroidal anti-inflammatory drugs, followed by paracetamol and opioid-containing medications, which was consistent with previous studies showing that management of OA in primary care may not conform to the recommendations in clinical practice guidelines or to the intensity of patients' pain.

“The fact that 54% of patients in this real-world setting had persistent moderate to severe pain suggests that currently prescribed pain treatments for knee OA are not meeting the needs of the majority of patients,” the authors concluded.