Safety Comparison of Analgesics to Treat Arthritis in Older Adults

In 2006, prescriptions for analgesics accounted for 230 million prescription purchases; 1 in 5 adults received a prescription for an analgesic that year. According to researchers, despite the widespread use of these medications, the comparative safety of analgesics has not been well documented. The safety of alternative analgesics is particularly unclear. Researchers recently conducted a study to examine the comparative safety of nonselective nonsteroidal anti-inflammatory drugs (nsNSAIDs), selective cyclooxygenase-2 inhibitors (coxibs), and opioids. They reported study results in Archives of Internal Medicine [2010;170(22):1968-1976]. The study cohort included Medicare beneficiaries from New Jersey and Pennsylvania who qualified for pharmaceutical assistance programs for lower-income older adults. These programs provided insurance coverage for all medications without restriction during the study period, January 1, 1999-December 31, 2005. Included in the analysis were eligible adults who had diagnoses for osteoarthritis or rheumatoid arthritis on 2 separate visits. Following the second diagnosis, eligible adults became part of the study cohort when their first new analgesic prescription (nsNSAID, coxib, or opioid) was filled. The patients were matched on propensity scores. The researchers analyzed the risk of adverse events related to the analgesics using incidence rates and adjusted hazard ratios from Cox proportional hazards regression. After applying exclusion criteria, the final study cohort included 12,840 members. The 3 propensity score–matched cohorts (nsNSAID [n=4280], coxib [n=4280], and opioid [n=4280]) were matched in baseline characteristics. Mean age was 80.0 years, 85% were female, and approximately 87% were white. In each group, >80% had osteoarthritis; the percentage of members with rheumatoid arthritis varied from 13.4% in the group using coxibs to 9.0% in the group using opioids. Compared with the other 2 groups, the number of acute care hospital days was higher in the opioid group. Comorbidity index, history of gastrointestinal (GI) tract disease, and use of gastroprotective medications were similar in the 3 groups. Compared with users of nsNSAIDs, relative risk of cardiovascular events was higher for users of coxibs (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.01-1.62) and for users of opioids (HR, 1.77; 95% CI, 1.39-2.24). GI tract bleeding was similar for opioid users, but reduced for coxib users (HR, 0.60; 95% CI, 0.35-1.00). Risk for fracture was similar with use of coxibs and nsNSAIDs, but elevated for users of opioids (HR, 4.47; 95% CI, 3.12-6.41). Compared with use of nsNSAIDs, use of opioids was associated with an increased risk of safety events that required hospitalization; there was no association with increased risk of hospitalization due to safety events for users of coxibs. Also compared with nsNSAIDs, use of opioids was associated with an increased risk of all-cause mortality (HR, 1.87; 95% CI, 1.39-2.53). There was no association with increased risk of all-cause mortality with coxib use. Limitations cited by the researchers include concerns about generalizability, possible misclassification of exposure and end points, and uncertainty about the direction and extent of bias in the analyses. In conclusion, the researchers noted that, “the comparative safety of analgesics varies depending on the safety event studied. Opioid use exhibits an increased relative risk of many safety events compared with nsNSAIDs.”