IIHTT
Trial question
What is the effect of acetazolamide in patients with idiopathic intracranial hypertension and mild visual loss?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
98.0% female
2.0% male
N = 165
165 patients (161 female, 4 male).
Inclusion criteria: patients with idiopathic intracranial hypertension and mild visual loss who received a low-sodium weight-reduction diet.
Key exclusion criteria: total treatment of idiopathic intracranial hypertension > 2 weeks; previous surgery for idiopathic intracranial hypertension; abnormal cerebrovascular fluid contents; abnormalities on neurologic examination aside from papilledema.
Interventions
N=86 acetazolamide (maximally tolerated dosage of up to 4 g/day for 6 months).
N=79 placebo (matching placebo for 6 months).
Primary outcome
Improvement in perimetric mean deviation in most affected eye at 6 months
1.43 dB
0.71 dB
1.4 dB
1.1 dB
0.7 dB
0.4 dB
0.0 dB
Acetazolamide
Placebo
Borderline significant
increase ▲
Borderline significantly greater improvement in perimetric mean deviation in the most affected eye at 6 months (1.43 dB vs. 0.71 dB; AD 0.71 dB, 95% CI 0 to 1.43).
Secondary outcomes
Significantly smaller improvement in papilledema grade (-1.31 vs. -0.61; AD -0.7 , 95% CI -0.99 to -0.41).
Significant increase in vision-related QoL (8.33 vs. 1.98; AD 6.35 , 95% CI 2.22 to 10.47).
Significant increase in weight reduction (7.5 kg vs. 3.45 kg; AD 4.05 kg, 95% CI 1.83 to 6.27).
Safety outcomes
No significant differences in dizziness, dyspnea, headache.
Significant differences in diarrhea (14.0% vs. 3.8%), vomiting (14.0% vs. 3.8%), dysgeusia (15.1% vs. 0%), paresthesia (47.7% vs. 6.3%), reduction in CO2 level (10.5% vs. 0%).
Conclusion
In patients with idiopathic intracranial hypertension and mild visual loss who received a low-sodium weight-reduction diet, acetazolamide was superior to placebo with respect to improvement in perimetric mean deviation in the most affected eye at 6 months.
Reference
NORDIC Idiopathic Intracranial Hypertension Study Group Writing Committee, Michael Wall, Michael P McDermott et al. Effect of acetazolamide on visual function in patients with idiopathic intracranial hypertension and mild visual loss: the idiopathic intracranial hypertension treatment trial. JAMA. 2014 Apr 23-30;311(16):1641-51.
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