IMPORTANCE: This study addresses the critical need for an evidence-based instrument to assess the likelihood of NSAID-induced cardiovascular events, that provides clinicians with valuable decision support to improve safety in their use for pain management, especially in patients vulnerable to cardiovascular events. OBJECTIVE: To develop a practical risk scoring tool, NSAID Induced Cardiovascular Events (NAÏVE), for estimating the risk of serious cardiovascular events associated with NSAID use. DESIGN: Retrospective nested case-control study. SETTING: The study leveraged data from the DAVINCI database, integrating electronic health records, administrative data, and clinical data from both the Veterans Health Administration (VHA) and the Department of Defense (DoD). PARTICIPANTS: The study cohort consisted of individuals with at least one NSAID pharmacy claim, with cases defined as those experiencing non-fatal myocardial infarction, non-fatal stroke, or new heart failure. INTERVENTIONS: Development of the NAÏVE risk scoring tool involved a comprehensive analysis of demographic, clinical, and prescription-related variables, including NSAID exposure, comorbidities, and medication history. MAIN OUTCOMES/MEASURES: The primary outcome was the first occurrence of a cardiovascular event. RESULTS: The study cohort comprised 231,967 cases and 2,319,670 controls, identified from individuals with at least one NSAID pharmacy claim between October 1, 2016, and September 30, 2020. The risk index, NAÏVE, demonstrated strong discriminatory ability and calibration, with a C-statistic of 0.88. Variables such as age, NSAID exposure, comorbidities, and medication history were associated with increased odds of NSAID-induced cardiovascular events. CONCLUSIONS/RELEVANCE: NAÏVE is the first evidence-based risk scoring tool providing clinicians with valuable decision support for assessing the potential risk of serious cardiovascular events associated with NSAID use. It fills a crucial gap in clinical practice, allowing for transparent discussions with patients and shared decision-making regarding NSAID prescriptions. Further validation and prospective testing are warranted for broader applicability.