Mortality and IIH
IH Registry Study Analyzes Causes of Death in IIH Patients Published in Neurology
The IH Registry (IHR), a project of the Intracranial Hypertension Research Foundation and Oregon Health & Science University, has published a study investigating the causes of death in IIH patients in the March 27, 2020 issue of Neurology, the journal of the American Academy of Neurology.
It is the first time ever that researchers have looked at whether mortality in IIH patients is different from that of the general population of the United States, as well examined the leading causes of death for this particular group of patients.
Understanding mortality rates and risks for all IH patients help to educate and most importantly, prevent unnecessary death.
This retrospective cohort study utilized data from the IHR, a database that contains medical records, imaging studies, participant-reported questionnaire data, and annual follow-up from individuals diagnosed with idiopathic and secondary intracranial hypertension.
A standardized mortality ratio (SMR) was calculated as the ratio of observed deaths, identified by National Death Index (NDI), divided by expected deaths, estimated utilizing indirect standardization with data extracted from the Underlying Cause of Death1999–2017 dataset published by the Centers for Disease Control and Prevention (CDC) Wonder Online Database.
There were 47 deaths (96% female) among 1,437 IHR participants that met the study’s inclusion criteria. The average age at death was 46 years
(range 20–95 years).
Participants of the IHR with IIH experienced higher all-cause mortality than the general population. Suicide, accidents, and deaths from medical/surgical complications* were the most common underlying causes, accounting for 43%
of all deaths.
Significant Discoveries:
- Over 50% of deaths were attributable to four underlying causes. The top two underlying causes of death were intentional self-harm and accidents (7 deaths each). The third most common cause was complications of medical/surgical care, which accounted for 6 deaths. Heart disease accounted for 5 deaths.
- Compared to the general population, the risk of suicide was over 6 times greater (SMR, 6.1; 95% CI, 2.9–12.7) and the risk of death from accidental overdose was over 3 times greater (SMR, 3.5; 95% CI, 1.6–7.7).The risk of suicide by overdose was over 15 times greater among the IHR cohort than in the general population (SMR, 15.3; 95% CI, 6.4–36.7)
- Participants of the IHR with IIH had a risk of all-cause mortality that was 50% higher than age- and sex-matched members of the general population.
- When compared to age- and sex-matched members of the general population, participants of the IHR with IIH possess significantly elevated risks of all-cause mortality, suicide, and accidental overdose. Taken together, suicide, accidental deaths, and death from complications of medical/surgical treatments accounted for 4 of every 10 deaths in this cohort.
Although IIH itself is not fatal, the elevated risk of death from suicide and accidental overdose among individuals with IIH is a characteristic often observed with chronic disorders that possess fatal outcomes such as multiple sclerosis, amyotrophic lateral sclerosis, and cancer.
Likely explanations for why IIH can lead to suicide and accidental overdose include the intractable nature of the disorder, elevated rates of mental illness, and the medical complexity of many IIH patients.
And while PTSD was only significantly associated with accidental overdose, elevated rates of suicidal ideation, as well as mental illnesses such as depression and bipolar disorder, present as modifiable factors, which may be targeted to reduce the number of deaths among IIH patients in the future.
The development of novel treatments designed specifically for treating IH, rather than the secondary use of existing treatments for other disorders, would also be a major step forward in resolving many of the debilitating signs and symptoms of IIH. Until then, health care professionals should consider mortality as a potential outcome of treatment failure.
*The researchers were not aware of any deaths within this cohort from complications of bariatric surgery, cerebral venous sinus stents, or optic nerve sheath decompressions.