Osteoarthritis is a joint disease that causes erosion of cartilage and leads to friction between bones. Its precise cause is unknown, though it has been linked to aging, specific occupations, trauma, genetics, and repetitive, small injuries over time. The rubbing causes pain, swelling, and loss of motion. About 6 percent of U.S. adults age 30 or older have osteoarthritis of the knee, and about 3 percent have osteoarthritis of the hip.
Two classes of drugs commonly used to treat osteoarthritis—non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2 inhibitors (a newer generation of NSAIDs)—present similar, increased risks of heart attacks while offering about the same level of pain relief, according to a new report by the Agency for Healthcare Research and Quality (AHRQ).
The exception is the drug naproxen, commonly sold as Aleve® or Naprosyn®, a medication that scientific evidence suggests presents a lower risk of heart attack for some patients than other NSAIDs or COX-2 inhibitors, the study concluded. Researchers emphasized in their analysis, however, that all drugs pose potential harms along with benefits. Patients differ widely on how they react to drugs, how they prioritize risks, and whether risks are acceptable when compared to a drug's benefits. Patients should talk to their doctors before changing any medications.
The report, authored by AHRQ's Evidence-based Practice Center at Oregon Health & Science University, was based on a systematic review of 360 published studies and represents the most comprehensive analysis thus far of arthritis pain medications. Researchers compared the pain medications' effectiveness and health risks, including heart attack and gastric side effects, plus identified topics where more research is needed. While the review yielded important findings about the painkillers, it concluded more studies are needed about the drugs' comparative risks, the consequences of long-term use, and the impact of dosing variations. The authors also suggested that genetic research may one day predict which patients are most likely to develop cardiovascular problems when taking the analgesics.
The AHRQ report, which was developed with ongoing input from experts and other members of the public, analyzed the risks and benefits of 26 medications. Among the conclusions:
In 2003, Americans spent about $36.6 billion on treatments for osteoarthritis and other non-traumatic joint disorders, including hospitalizations, surgeries, diagnostic tests, drugs, home care and other interventions, according to Federal estimates. Of this amount, about $5.5 billion was spent on COX-2 inhibitors and $3 billion on other NSAIDs.
Traditional NSAIDs work by inhibiting the action of two related enzymes. One of the enzymes reduces inflammation, eases pain and prevents blood clotting. But the intervention also limits the other enzyme's ability to protect the stomach lining from digestive chemicals and help maintain kidney function. Each year, an estimated 16,500 people die due to NSAID-induced gastrointestinal problems.
The new report, Comparative Effectiveness and Safety of Analgesics for Osteoarthritis, is available at http://effectivehealthcare.ahrq.gov/healthInfo.cfm?infotype=rr&ProcessID=2&DocID=67. Reprints of the Executive Summary (AHRQ Publication No. 06-EHC009-1) are available free on a single-copy basis while supplies last from the AHRQ Publications Clearinghouse.
Editor's Note: The report, Comparative Effectiveness and Safety of Analgesics for Osteoarthritis, is the latest in a series of Comparative Effectiveness Reviews produced by AHRQ's Effective Health Care Program, the first Federal program to compare alternative treatments for health conditions and make the findings public. The program is intended to help patients, health care providers, and others choose the most effective treatments. Information on the program and other comparative effectiveness reviews can be found at http://www.effectivehealthcare.ahrq.gov.