The mean improvement in PMD was greater with acetazolamide ( 1.43 dB , from -3.53 dB at baseline to -2.10 dB at month 6 ; n = 86 ) than with placebo ( 0.71 dB , from -3.53 dB to -2.82 dB ; n = 79 ) ; the difference was 0.71 dB ( 95 % CI , 0 to 1.43 dB ; P = .050 ) .