Trigeminal neuralgia and its comorbidities: a nationwide disease trajectory study

There is a limited understanding of risk factors and comorbidities in trigeminal neuralgia, a disease characterized by paroxysms of severe unilateral facial pain and a higher incidence in women. We aim to identify temporally associated comorbidities involving trigeminal neuralgia by analyzing nationwide disease trajectories. Using data from 7.2 million unique individuals in the Danish National Patient Register between 1994 and 2018, each individual diagnosed with trigeminal neuralgia was compared with 10,000 matched controls to identify co-occurring diseases. The sequential disease associations were identified in sex-stratified disease trajectories. A Cox-regression analysis investigated whether treatment with carbamazepine or oxcarbazepine, as compared with gabapentin, pregabalin, or lamotrigine, was associated with stroke risk. Finally, we investigated the stroke polygenic risk score and its association with stroke incidence in a subset of genotyped individuals with trigeminal neuralgia. We included 7141 individuals with trigeminal neuralgia (64.2% female, mean age at diagnosis 58.7 years) and identified 18 diseases associated with subsequent trigeminal neuralgia. After diagnosis, trigeminal neuralgia was associated with 9 diseases, including ischemic stroke (relative risk 1.55). Carbamazepine or oxcarbazepine treatment increased the ischemic stroke risk (hazard ratio 1.78; 95% confidence interval 1.47-2.17); however, the polygenic risk of stroke showed no association. In the Danish population, a trigeminal neuralgia diagnosis is temporally associated with 27 diseases revealed in systematic disease trajectories. Trigeminal neuralgia itself and its first-line treatment, but not a stroke polygenic risk score, was associated with an increased risk of ischemic stroke indicating that vascular risk factors should be routinely assessed in individuals with trigeminal neuralgia.