Best Evidence Topics

Randomised control trial

Westerlaken B. O, Stokroos R. J, Dhooge I. J. et al
Treatment of Idiopathic Sudden Sensorineural Hearing loss with Antiviral Therapy: A Prospective, Randomized Double-Blind Clinical Trial
Ann Otol Rhinol Laryngol
2003; 112: 993-1000
  • Submitted by:Anna Morgan - ST6 Emergency Medicine
  • Institution:Homerton Hospital
  • Date submitted:17th May 2011
Before CA, i rated this paper: 6/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes, to evaluate the therapeutic value of acyclovir in the treatment of idiopathic sudden sensorineural hearing loss.
2 Design
2.1 Is the study design suitable for the objectives
  Yes it is a randomised double-blind clinical trial.
2.2 Who / what was studied?
  Multicentre trial in the Netherlands, enrolled 90 patients. Inclusion criteria = (1) sensorineural hearing loss of unknown cause, (2) hearing loss greater or equal to 30 dB for 3 subsequent 1 octave steps in frequency in standard pure tone audiogram (3) blank otologic history, (4) hearing loss occurring within a period of 24 hours. Exclusion criteria, hearing loss over 14 days ago or contraindications to prednisolone or acyclovir.
2.3 Was this the right sample to answer the objectives?
2.4 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
  Sample size estimate was performed. There was a larger range in hearing recovery than was expected (SD 20.5 dB in placebo and 24.4 dB in treatment goup) . This means that the sample size used for analysis (70) may have been too small to achieve the objectives of the study. The power calculation made prior to the study estimated that a sample of 126 would be needed if the standard deviation in hearing recovery was 20.
2.5 Were all subjects accounted for?
  16 patients were excluded from analysis because of administrative problems (case record form not correctly documented). This is a large number.
2.6 Were all appropriate outcomes considered?
2.7 Has ethical approval been obtained if appropriate?
2.8 Were the patients randomised between treatments?
2.9 How was randomisation carried out?
  Done in blocks of 4 by pharmacist.
2.10 Are the outcomes clinically relevant?
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  Yes, primary outcome was hearing recovery as measured by auditometry (pure tone and speech discrimination) and secondary outcome was subjective recording of perceived hearing recovery, tinnitus intensity, pressure sensation and vertigo severity.
3.2 Are the measurements valid?
3.3 Are the measurements reliable?
3.4 Are the measurements reproducible?
3.5 Were the patients and the investigators blinded?
4 Presentation of results
4.1 Are the basic data adequately described?
4.2 Were groups comparable at baseline?
  No, failed to control for severity of initial hearing loss, there was a statistically significant difference between the treatment and the control group on this measure. The mean hearing loss at admission in the acyclovir group was 62.9 dB HL, whereas in the placebo group the mean hearing loss was 83.6 dB HL. This difference was statistically significant (p = 0.002)
4.3 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
4.4 Are the results internally consistent, i.e. do the numbers add up properly?
4.5 Were side effects reported?
  Yes, no specific side effects were reported with acyclovir.
5 Analysis
5.1 Are the data suitable for analysis?
5.2 Are the methods appropriate to the data?
5.3 Are any statistics correctly performed and interpreted?
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
6.2 Is the discussion biased?
7 Interpretation
7.1 Are the authors' conclusions justified by the data?
7.2 What level of evidence has this paper presented? (using CEBM levels)
7.3 Does this paper help me answer my problem?
  The paper does not support the use of acyclovir in the treatment of idipathic sudden senorineural hearing loss and I do not intend to use it in clinical practice. It is possible that a small benefit in using acyclovir could be missed by this study due to its small size.
After CA, i rated this paper: 6/10
8 Implementation
8.1 Can any necessary change be implemented in practice?
  Based on this paper I do not intend to use acyclovir in patients in the treatment of idiopathic sudden sensorineural hearing loss.
8.2 What aids to implementation exist?
8.3 What barriers to implementation exist?