Healthy Skepticism International News
July 2001
Hormone Replacement Therapy: Gallbladder disease
Results:
36% of 1140 respondents indicated that the impact of HRT on increasing or decreasing the risk of gallbladder disease was very uncertain.
63% of 1139 respondents indicated that regarding gallbladder disease, HRT was likely to be neutral.
There was a significant negative correlation between respondent’s level of certainty and their estimate of benefit. (Spearman’s rho = -0.51 p
<0.0001) Those who felt more certain were more likely to believe that HRT had a harmful effect on gallbladder disease rates.
Our comment:
The impact of HRT on gallbladder disease is very uncertain but may be very harmful.
Explanation:
In the HERS trial the rate of gallbladder disease was 4.5% in the placebo group vs 6.1% in the HRT group. (p = 0.05 ie borderline statistical significance). Results from ERA are consistent with that but the numbers were too small to have the power to show statistical significance if it exists. The possibility that the difference seen in the HERS trial was only due to chance should be taken seriously because the significance is borderline and so it needs to be verified in other trials. Also if trials measure many secondary endpoints then 5% of the endpoints will have differences of borderline significance (around p=0.50) just by chance alone.
Gallbladder disease is usually not fatal but is relatively common and can be severe.
Next: Options recommended for Ann
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