Investigations of migraine among childhood cancer survivors have predominantly relied on self-reported information and hospital discharge diagnoses. Alone, both approaches are liable to bias. We used Danish nationwide registers to obtain data on both prescriptions of acute migraine medications (antimigraines) and hospital discharge diagnoses of migraine to assess the relative risk of migraine across a wider spectrum of migraine presentations than previously studied.
We followed a Danish population-based cohort of 7771 individuals with childhood cancer diagnosed in the period from Jan 1st, 1978 to Dec 31st, 2017, for risk of prescription antimigraine initiation and for risk of hospitalization due to migraine. Rates of hospitalization were assessed for the entire follow-up period whereas rates of antimigraine initiations were assessed in the period from Jan 1st, 1997, to Dec 31st, 2017. Relative to the general population without childhood cancer, standardized incidence ratios (SIRs) were calculated for each outcome.
Individuals exposed to childhood cancer were at increased risk of antimigraine initiation (SIR of 1.24, 95% CI: 1.11–1.38) and of migraine hospitalization (SIR of 2.44, 95% CI: 1.87–3.12) from the day of their cancer diagnosis and up to 40 years after.
Individuals diagnosed with childhood cancer have a higher risk of migraine of varying presentations, in addition to migraine resulting in hospitalization as previously reported. This potentially preventable problem warrants clinical attention.
- • Danish nationwide registers give unbiased estimates of migraine prevalence among individuals diagnosed with childhood cancer.
- • Childhood cancer confers increased risk of initiating prescription migraine therapy and being hospitalized for migraine.
- • Individuals diagnosed at 15-19 years of age reflect an increased burden of psychological sequela compared to younger peers.
The treatment of childhood cancer has improved substantially in recent decades . Accordingly, increasing numbers of childhood cancer patients experience remission and cure. Over the past decades, however, it has become clear that childhood cancer survivors may experience, to varying degrees, a wide range of chronic health conditions resulting from previous therapeutic exposures , one of which is migraine headaches .
Migraine is a common and frequently disabling neurological disorder characterized by severe and recurring unilateral headaches and accompanying symptoms, known as migraine attacks . Although data are still scarce, migraine headaches may be among the most common complications experienced by childhood cancer survivors. Indeed, a migraine prevalence of more than 30% among childhood cancer survivors has been reported in two previously published investigations .
Until now, the assessment of migraine risk in childhood cancer survivors has predominantly relied on either self-reported information or been investigated by means of in-patient hospital discharge diagnoses, and either approach can be encumbered by its own set of limitations. Studies relying on self-reported information are typically vulnerable to both participation and recall bias, and potentially to misclassification . Studies based on hospital discharge diagnoses may suffer from surveillance bias as well as low sensitivity to detect migraine in the population since hospitalization due to migraine is rare .
Effective acute treatment for migraine attacks is crucial to alleviate the significant personal and socio-economic burden imposed by this disorder . In recent times, the acute treatment of migraine has predominantly been based on potent serotonin 5-HT1B/1D-receptor agonists, collectively termed triptans . In Denmark, triptans have mostly replaced older drug therapies for acute migraine treatment comprised of dihydroergotamines and ergotamines , and can only be purchased via prescription from a doctor .
Since 1994, all prescriptions dispensed by non-hospital pharmacies in Denmark have been recorded in the Danish Prescription Register . In combination with other Danish health registers , this data resource enabled us to conduct a population-based study in which in-patient discharge diagnoses of migraine were supplemented by prescriptions of antimigraine medications to assess the relative risk of migraine of varying presentations among individuals diagnosed with childhood cancer.