A Retrospective Database Study of Gastrointestinal Events and Medical Costs Associated with Nonsteroidal Anti-Inflammatory Drugs in Japanese Patients of Working Age with Osteoarthritis and Chronic Low Back Pain

Introduction: Nonsteroidal anti-inflammatory drugs (NSAIDs) have long-term benefits but are limited by side effects. We assessed the health and economic burden of renal events associated with NSAID use in patients with osteoarthritis (OA) and/or chronic low back pain (CLBP). Methods: This retrospective, large-scale, medical claims database study of Japanese patients receiving NSAIDs for OA and/or CLBP between 2009 and 2018 assessed the incidence of renal events and effect of treatment duration, mode of administration, and usage consistency of NSAIDs. Results: Of 180,371 patients, NSAIDs were prescribed as first-line analgesics in 89.3%. Incidence per 10,000 person-years (95% confidence interval [CI]) for renal events was 23.46 (21.84-25.08) and for progression of chronic kidney disease (CKD) was 267.12 (189.93-344.32). Longer treatment duration (> 1 to <= 3 years, risk ratio [RR] 1.32, 95% CI 1.12-1.54; P = 0.0007; > 3 to <= 5 years, RR: 1.38, 95% CI 1.04-1.84; P = 0.0254 vs. < 1 year) and consistent use (RR: 1.24, 95% CI 0.99-1.55; P = 0.0595) increased the risk of renal events but the latter did not reach statistical significance. The risk was similar in patients using patch/oral NSAIDs and high in elderly patients and in those with diabetes, hypertension, and other cardiovascular disease. Following a renal event, median 1-year cost of drug treatment was $27.90; hospitalization, $1779.40; and dialysis, $33,018.40. Conclusions: Risk of renal events significantly increased with prolonged and consistent NSAID use (irrespective of mode of administration), with age, and in patients with certain comorbidities. Careful NSAID use is recommended in patients with CKD and those at high risk for CKD.