Morbidity and mortality risks associated with valproate withdrawal in young men and women with epilepsy

: Valproate is the most effective treatment for idiopathic generalised epilepsy. Current guidance precludes its use in women of childbearing potential, unless other treatments are ineffective or not tolerated, because of high teratogenicity. This risk was recently extended to men. New guidance will limit use both in men and women aged <55 years, resulting in withdrawal of valproate from men already taking it, as occurs for women. Whether there are risks of personal harm (including injury or death) associated with valproate withdrawal has not yet been quantified for men or women on valproate, meaning clinicians cannot reliably counsel either sex when discussing valproate withdrawal with them, despite that this concern may be at the forefront of patients' and clinicians' minds. We assessed whether there are any morbidity or mortality risks associated with valproate withdrawal in young men and women. We performed a retrospective cohort study of internationally derived electronic health data within the TriNetX Global Collaborative Network. Included were men and women aged 16-54 years with ≥1 epilepsy disease or symptom code between 01/12/2017-01/12/2018 and ≥2 valproate prescriptions over the preceding two years (01/01/2015-30/11/2017). 5-year propensity-matched risks of mortality and a range of morbidity outcomes were compared between those remaining on vs. withdrawn from valproate during the 01/12/2017-01/12/2018 recruitment period, regardless of whether switched to another antiseizure medication. Survival analysis was undertaken using Cox-proportional hazard models, generating hazard ratios (HRs) with 95% confidence intervals (CIs). 8,991 men and 5,243 women taking valproate were recruited. 28% of men and 36% of women were subsequently withdrawn from valproate. Valproate withdrawal was associated with significantly increased risks of emergency department attendance (HRs overall: 1.236 (CI 1.159-1.319), men: 1.181 (CI 1.083-1.288), women: 1.242 (CI 1.125-1.371)), hospital admission (HRs overall: 1.160 (CI 1.081-1.246), men: 1.132 (CI 1.027-1.249), women: 1.147 (CI 1.033-1.274)), falls (HRs overall: 1.179 (CI 1.041-1.336), men: 1.298 (CI 1.090-1.546)), injuries (HRs overall: 1.095 (CI 1.021-1.174), men: 1.129 (CI 1.029-1.239)), burns (HRs overall: 1.592 (CI 1.084-2.337)), and new-onset depression (HRs overall 1.323 (CI 1.119-1.565), women: 1.359 (CI 1.074-1.720)). The risk of these outcomes occurring was 1-7% higher in those withdrawn from valproate than in those remaining on valproate. Overall, valproate withdrawal was not associated with increased mortality. These results may help patients and clinicians have a more informed discussion about personal safety when considering valproate withdrawal.