Risk of Major Adverse Cardiovascular Events following Nicotinamide Exposure: Cohort Study

IMPORTANCE. Nicotinamide metabolites have recently been implicated in increased risk of major cardiovascular events (MACE). Supportive data about clinical risk of MACE for nicotinamide users is lacking. OBJECTIVE. To determine whether nicotinamide use results in an increase of MACE. DESIGN, SETTING, PARTICIPANTS. Retrospective cohort study of two patient cohorts, Vanderbilt University Medical Center (VUMC) and Military Veteran Program (MVP). The risk of MACE in patients exposed to nicotinamide was compared to the risk of MACE in unexposed patients. In the VUMC cohort, 1228 patients were exposed to nicotinamide based on keyword entry for 'nicotinamide' or 'niacinamide' and hand-review of charts, while 253 were unexposed but had documented recommendation for use. In the MVP cohort, there were 1594 with exposure to nicotinamide propensity score matched to 2694 without exposure. EXPOSURES. The primary exposure for the VUMC cohort was a confirmed exposure to nicotinamide in chart review. The primary exposure for the MVP cohort was medication entry for 'nicotinamide' or 'niacinamide'. MAIN OUTCOME(S) AND MEASURE(S). The primary outcome was development of MACE based on a validated phenotype. RESULTS. Between both cohorts, 6039 patients were included, of whom 5125 were male with a mean age of 63.2 years. Neither cohort had significant differences in mean age, sex, race and ethnicity between the nicotinamide exposed and unexposed groups. In the VUMC cohort, there was no significant association between nicotinamide exposure and the primary outcome of MACE (HR 0.76, 95% CI 0.46 - 1.25, p = 0.28). MACE prior to nicotinamide exposure was strongly associated with subsequent MACE (HR 9.01, 95% CI 5.90 - 13.70, p < 0.001). In the MVP cohort, we adjusted for MACE risk factors as potential confounding variables and saw no significant association between nicotinamide exposure and MACE (HR 1.00 95% CI 0.75 - 1.32), while history of prior MACE remained strongly associated with subsequent MACE (HR 9.50, 95% CI 6.38 - 14.1). CONCLUSIONS AND RELEVANCE. In this retrospective cohort study of 6039 adults from two different patient populations, we found no increased risk of MACE in patients with nicotinamide exposure.