An RCT of Bariatric Surgery vs a Community Weight Loss Programme for the Sustained Treatment of IIH (IIH:WT)

A Randomised Controlled Trial of Bariatric Surgery Versus a Community Weight Loss Programme for the Sustained Treatment of Idiopathic Intracranial Hypertension: the IIH:WT Trial

Idiopathic intracranial hypertension (IIH) is a condition with an unknown cause or causes. The condition is associated with raised pressure in the brain and can cause disabling daily headaches and loss of sight, which can be permanent. The raised brain pressure squashes the nerves supplying the eye (also known as papilloedema) and this can affect vision. Over 90% of patients with IIH are overweight and weight loss is the most effective treatment. Other treatments for IIH have very little current evidence to support their use. Weight loss is difficult to maintain. This trial aims to compare two methods of weight loss, bariatric surgery and the most effective dietary programme commonly available, Weight Watchers, to see which offers the most effective sustainable treatment for IIH. Bariatric surgery is recommended by the NICE clinical guidelines for patients with a Body Mass Index (BMI) of over 40, or over 35 with a co-morbidity. Women suffering from IIH have a BMI on average around 38 and IIH is not recognised as a co-morbidity for bariatric surgery. This trial will recruit 64 women with IIH from Neurology and Ophthalmology clinics in UK NHS Trusts. They will be randomised and 32 participants will be allocated to the dietetic intervention arm, and be enrolled in their local Weight Watchers group. 32 participants will be allocated to the bariatric surgery arm, and will be referred to their local bariatric surgery pathway to receive bariatric surgery. Both groups of participants will be allocated to a treatment arm which is proven to bring about weight loss. Participants will then be followed up for five years, with the most important measurement being their brain pressure after one year of being in the trial. A further 20 obese women who don't suffer from IIH will be recruited to compare the baseline symptoms and biomarkers of those with IIH; they will take no further part in the study. 5 further healthy individuals will be scanned twice in an MRI test group to validate the MRI scan sequence to be used in the trial.

Participants randomised to the dietetic arm will be given vouchers at baseline, 3, 6 and 9 months that exempt them from paying for consecutive and specified weeks of their local Weight Watchers diet programme.

Patients randomised to the bariatric surgery arm will be referred to the bariatric surgery pathway and, if judged suitable according to the bariatric surgery clinic's screening processes, undergo bariatric surgery.

To evaluate the baseline difference in ICP between IIH patients and a matched obese control cohort we will recruit 20 obese but otherwise healthy participants who will undergo the same baseline visit as the main trial participants and then exit the study.

5 patients will undergo double baseline MR scans to validate the novel MR sequences being used in the main trial.

Participants randomised to the bariatric surgery arm of the trial will be referred to the surgery pathway according to NICE guidelines at Birmingham Heartlands Hospital (BHH), Heart of England NHS Foundation Trust.

Participants randomised to the dietetic arm will be given vouchers at baseline, 3, 6 and 9 months that exempt them from paying for consecutive and specified weeks of their local Weight Watchers.

Change in Intracranial Pressure (ICP) between baseline and 12 months. ICP will be assessed using lumbar puncture (LP). To avoid the LP affecting the visual measures it will be performed after the visual tests have been completed. ICP will be recorded to the nearest whole number in cmH2O. Both opening and closing ICP will be recorded.

Change in ICP between baseline and 24 and 60 months. ICP will be assessed using lumbar puncture (LP). To avoid the LP affecting the visual measures it will be performed after the visual tests have been completed. ICP will be recorded to the nearest whole number in cmH2O. Both opening and closing ICP will be recorded.

Change in visual function from 0 to 12 months (and at 24 and 60 months). Assessments to be undertaken are the LogMAR (log of the minimum angle of resolution) chart to assess visual acuity, automated perimetry (Humphrey 24-2 central threshold) to measure the visual field mean deviation, an evaluation of contrast sensitivity and an Ishihara book to assess colour vision. The pupils will then be dilated using 1% tropicamide. Papilloedema will then be measured using spectral optical coherence tomography. Papilloedema will be further graded following fundus photographs. This will be done after all participants have reached the primary endpoint by two neuro-ophthalmologists blinded to trial treatment arm. The assessors will score the paired papilloedema images as better/same/worse as per the methodology described in a previous study. They will also assign a Frisen score to the images.

Change in headache associated disability from 0 to 12 months (and at 24 and 60 months). Headache will be assessed by participant completed questionnaires. Participants will complete a daily headache diary in the week before assessments, which will evaluate the Headache Index score and use of analgesia (days/week). Headache associated disability will be evaluated using the Headache Impact Test-6 score (HIT 6). Severity and frequency of headaches will be assessed retrospectively using the Headache Index. Headache phenotype (according to criteria from the International Headache Society) will also be assessed.

Change in anthropometric measures (e.g. waist, hip, fat mass) from 0 to 12 months (and at 24 and 60 months)

Difference in number of referrals to cerebrospinal fluid (CSF) shunting procedures and optic nerve sheath fenestration between treatment arms at 0 to 12 months (and at 24 and 60 months)

Comparison between IIH patients and the matched control group at baseline with respect to biomarkers and ICP.

Inclusion Criteria: Female IIH patients aged between 18 and 55 years, diagnosed according to the modified Dandy criteria who have chronic (> 6 months duration), active disease (papilloedema [Frisen grade ≥ 1], significantly raised ICP > 25cmH2O) and no evidence of venous sinus thrombosis (magnetic resonance or CT imaging and venography as noted at diagnosis). BMI >35kg/m2. Tried other appropriate non-surgical treatments to lose weight but have not been able to achieve or maintain adequate, clinically beneficial weight loss for at least 6 months. Able to give informed consent. Exclusion Criteria: Age less than 18 or older than 55 years. Pregnant or planning to conceive during the first 18 months of the trial . Significant co-morbidity, endocrinopathy or the use of hormone manipulating medication (excluding contraception and topical or inhaled steroids). Undergone optic nerve sheath fenestration. Definite indication for or contraindication against surgery or dieting. Have a specific medical or psychiatric contraindication for surgery, including drug misuse, eating disorder or major depression (suicidal ideation, drug overdose or psychological admission in last 12 months). Previous bariatric surgery. Taken AZD4017 within the last four months . Inability to give informed consent e.g. due to cognitive impairment.

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Yiangou A, Mitchell JL, Nicholls M, Chong YJ, Vijay V, Wakerley BR, Lavery GG, Tahrani AA, Mollan SP, Sinclair AJ. Obstructive sleep apnoea in women with idiopathic intracranial hypertension: a sub-study of the idiopathic intracranial hypertension weight randomised controlled trial (IIH: WT). J Neurol. 2022 Apr;269(4):1945-1956. doi: 10.1007/s00415-021-10700-9. Epub 2021 Aug 22.

Mollan SP, Mitchell JL, Ottridge RS, Aguiar M, Yiangou A, Alimajstorovic Z, Cartwright DM, Grech O, Lavery GG, Westgate CSJ, Vijay V, Scotton W, Wakerley BR, Matthews TD, Ansons A, Hickman SJ, Benzimra J, Rick C, Singhal R, Tahrani AA, Brock K, Frew E, Sinclair AJ. Effectiveness of Bariatric Surgery vs Community Weight Management Intervention for the Treatment of Idiopathic Intracranial Hypertension: A Randomized Clinical Trial. JAMA Neurol. 2021 Jun 1;78(6):678-686. doi: 10.1001/jamaneurol.2021.0659. Erratum In: JAMA Neurol. 2021 Jul 1;78(7):882.

Ottridge R, Mollan SP, Botfield H, Frew E, Ives NJ, Matthews T, Mitchell J, Rick C, Singhal R, Woolley R, Sinclair AJ. Randomised controlled trial of bariatric surgery versus a community weight loss programme for the sustained treatment of idiopathic intracranial hypertension: the Idiopathic Intracranial Hypertension Weight Trial (IIH:WT) protocol. BMJ Open. 2017 Sep 27;7(9):e017426. doi: 10.1136/bmjopen-2017-017426.