Benefits and Risks of Nonsteroidal Anti-inflammatory Drugs: Methodologic Limitations Lead to Clinical Uncertainties

Nonsteroidal anti-inflammatory drugs (NSAIDs) include traditional (tNSAIDs), such as ibuprofen, naproxen, and diclofenac, as well as selective cyclooxygenase-2 inhibitors (COXIBs), principally celecoxib. COXIBs were developed to decrease gastrointestinal side effects. Recently, the US Food and Drug Administration strengthened its warning about the risks of non-aspirin NSAIDs on myocardial infarction and stroke. The Cyclooxygenase 2 and Non-Steroidal Anti-Inflammatory Drug Trialist collaboration conducted a comprehensive worldwide meta-analysis using individual patient data exploring the risks of various COXIBs and NSAIDs on cardiovascular disease (CVD). Recently, the results of the Prospective Randomized Evaluation of Celecoxib Integrated Safety versus Ibuprofen or Naproxen (PRECISION) trial were published that tested risks of COXIBs and NSAIDs on CVD. Generally, data from meta-analyses of trials not designed a priori to test hypotheses are less reliable than large-scale randomized trials to test small to moderate benefits or harm. When the sample size is large, randomization provides control of confounding not possible to achieve in any observational study. Further, observational studies, and especially claims data, have inherent confounding by indication larger than the effects being sought. Nonetheless, trials must be of sufficient size and duration and achieve high compliance and follow-up to avoid bias and confounding. In this regard, PRECISION has high rates of nonadherence and losses to follow-up that may have introduced bias and confounding. At present, therefore, it may be most prudent for clinicians to remain uncertain about benefits and risks of these drugs and make individual clinical judgments for each of their patients.