Numbers needed to treat calculated from responder rates give a better indication of efficacy in osteoarthritis trials than mean pain scores
2008

Better Measures of Efficacy in Osteoarthritis Trials

Sample size: 605 publication Evidence: moderate

Author Information

Author(s): R. Andrew Moore, Owen A. Moore, Sheena Derry, Henry J. McQuay

Primary Institution: Pain Research and Nuffield Department of Anaesthetics, University of Oxford

Hypothesis

Does dichotomous responder analysis provide a more informative interpretation of drug efficacy in osteoarthritis trials than mean pain scores?

Conclusion

Responder analysis is more sensitive than average changes in VAS pain scores in assessing drug efficacy.

Supporting Evidence

  • 30% of patients achieved at least 20% pain relief with placebo, while 74% achieved this with 60 mg etoricoxib.
  • The NNT for 30 mg etoricoxib to achieve at least 50% pain relief was 4.2.
  • The NNT for 60 mg etoricoxib to achieve at least 50% pain relief was 2.6.

Takeaway

This study shows that looking at how many people get better with a treatment is more helpful than just looking at average pain scores.

Methodology

The study analyzed data from a double-blind, randomized trial comparing placebo and various doses of etoricoxib over 6 weeks.

Potential Biases

Potential bias due to reliance on data from a single trial and the involvement of a pharmaceutical company.

Limitations

The study is limited by its size and the use of data from only one trial.

Participant Demographics

Predominantly female (72%) and white (89%), aged 40 to 87 years, with a median arthritis duration of 6 years.

Statistical Information

P-Value

4.2 for 30 mg and 2.6 for 60 mg etoricoxib

Confidence Interval

95% CI 3.8 to 8.6 for 30 mg and 2.0 to 3.9 for 60 mg

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1186/ar2394

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