Self-Reported Weight and Height Among Idiopathic Intracranial Hypertension Patients

Idiopathic intracranial hypertension (IIH) mostly affects overweight and obese women. Severe obesity is associated with poorer visual outcomes in IIH, and weight gain can precipitate IIH and increase the risk of recurrence. Conversely, weight loss can decrease intracranial pressure and is an effective IIH treatment. Therefore, accurate monitoring of weight and body mass index (BMI) is important to help guide the management of IIH patients. Our goal was to compare estimated and measured BMI among patients with presumed IIH and non-IIH controls to determine whether these vital signs should be systematically measured when evaluating patients for IIH.

A retrospective chart review was performed of consecutive patients with reported and measured weight and height seen in one ophthalmology-based neuro-ophthalmology clinic for IIH between January 2, 2018 and September 10, 2018. Patients with IIH or presumed IIH were compared to non-IIH controls, matched according to age (±5 years), BMI (±5 kg/m unless ≥40 kg/m), sex, and race. Patients with confirmed IIH were asked to self-report their weight when seen in follow-up and they were weighed to compare their self-reported vs measured percent weight change.

We included 379 subjects (140 patients; 239 controls) among whom 75 of the IIH patients were matched to non-IIH controls. Patients with presumed or definite IIH accurately estimated their height and generally underestimated their weight by a median of 1.8 kg (4 lb), resulting in a median BMI underestimate of 0.9 kg/m. There was no difference in BMI underestimation when comparing presumed or definite IIH patients to matched non-IIH controls while controlling for insurance status, smoking, diabetes, and vascular disease (P = 0.66). As BMI increased, all subjects underestimated their BMI more (by 0.9% per 10 measured BMI unit increase), when controlling for age, sex, and race (P < 0.003). Sixteen confirmed IIH patients were seen in follow-up. At initial neuro-ophthalmology consultation, these subjects underestimated their weight by a mean of 3.2%. At last follow-up they underestimated their weight by only 1.2% (P = 0.03).

There was no evidence that IIH or presumed IIH patients had a different perception of their weight than non-IIH controls at initial neuro-ophthalmology consultation. Both patients and matched controls tended to underestimate their weight by the same amount, resulting in an overall BMI underestimation of approximately 1% per 10 measured BMI unit increase. Heavier subjects tended to underestimate their body weight and resultant BMI more, and IIH patients tended to estimate their weight more accurately at follow-up. Our results emphasize the need to systematically objectively measure the weight of presumed IIH patients seen in an ophthalmology clinic.