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

Valproate is the most effective treatment for idiopathic generalized epilepsy. Current guidance precludes its use in females of childbearing potential, unless other treatments are ineffective or not tolerated, because of high teratogenicity. This risk was recently extended to males. New guidance will limit use both in males and females aged <55 years, resulting in withdrawal of valproate from males already taking it, as occurs for females. Whether there are risks of personal harm (including injury or death) associated with valproate withdrawal has not yet been quantified for males or females 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 males and females. We performed a retrospective cohort study of internationally derived electronic health data within the TriNetX Global Collaborative Network. Included were males and females aged 16-54 years with ≥1 epilepsy disease or symptom code between 1 December 2017 and 1 December 2018, and ≥2 valproate prescriptions over the preceding 2 years (1 January 2015-30 November 2017). Five-year propensity-matched risks of mortality and a range of morbidity outcomes were compared between those remaining ON versus withdrawn from valproate during the 1 December 2017-1 December 2018 recruitment period, regardless of whether switched to another antiseizure medication.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). In total, 8991 males and 5243 females taking valproate were recruited. Twenty-eight per cent of males and 36% of females were subsequently withdrawn from valproate.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), males: 1.181 (CI 1.083-1.288), females: 1.242 (CI 1.125-1.371), hospital admission HRs overall: 1.160 (CI 1.081-1.246), males: 1.132 (CI 1.027-1.249), females: 1.147 (CI 1.033-1.274), falls HRs overall: 1.179 (CI 1.041-1.336), males: 1.298 (CI 1.090-1.546), injuries HRs overall: 1.095 (CI 1.021-1.174), males: 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), females: 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.