Ball 2011.

Methods	Multicentre, open‐label, parallel‐group RCT.
Participants	Participants had IIH that met Friedman's criteria (Friedman 2002). 50 participants from six UK centres. Two arms: 25 randomised to treatment with acetazolamide and 25 randomised to placebo.
Interventions	Participants were randomised to either the acetazolamide group or the placebo group. All participants were encouraged to lose weight.
Outcomes	Measured at baseline, 3, 6, 9 and 12 months. Primary outcomes were measured as an aggregate score (out of 15) on final visit (each outcome measure was ranked as being: absent (0); present, stable (1); deteriorating (2)): Headache. Tinnitus. Visual obscurations. Visual acuity. Optic disc appearance. Visual field. Secondary outcomes (and methods): Headache (10‐point scale). Tinnitus (subjective presence versus absence). Visual acuity (LogMAR chart). Visual obscurations (absent, present, or deteriorating). Visual fields (automated Humphrey perimetry). Contrast sensitivity (Pelli‐Robson chart). Papilloedema. Anxiety/depression (Hospital Anxiety and Depression Scale). Patient rated health status (EuroQoL and Short Form 36). Right and left eye data were reported separately.
Notes	In addition, at 12 months, clinicians were asked to select the term that best described the participant from the following options: IIH in remission. Active IIH improving. Active IIH but stable. Active IIH deteriorating. Date study conducted: Participants were followed until 12 months. No dates reported. Funding: Department of Neurology, University of Birmingham. Conflict of interest: None declared. Trial registration ID: EudraCT number 2004‐001595‐40.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants randomised by computer‐generated random list. No difference in baseline characteristics detected between arms.
Allocation concealment (selection bias)	Low risk	Neither participant or treating clinician was masked to allocation. Allocation was communicated to treating clinicians via telephone.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Neither participant or treating clinician was masked to allocation. Dosing schedules for acetazolamide decided by prescribing clinician.
Blinding of outcome assessment (detection bias) All outcomes	High risk	No masking of assessor reported.
Incomplete outcome data (attrition bias) All outcomes	High risk	Five participants from the placebo arm started on acetazolamide therapy. Two participants (one from each of the two arms) underwent surgical intervention. 12 participants from the acetazolamide arm discontinued treatment during the study period.
Selective reporting (reporting bias)	Low risk	Primary outcome data provided in full. Data not provided for anxiety, depression, patient reported health status assessment.