- Joined
- Oct 13, 2013
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That old chestnut!!!ALLHAT
Even a double randomised controlled CASE ONLY study can be seriously defective -
1) The subjects were already on BP meds then they were swopped to a randomised drug. What did they swop from?. To what extent was the observed differences influenced by swopping out of their usual meds. The discontinuation of BP meds does not mean cessation of its benefits which may carry on for some years. BP meds may have more benefit other than reduction in BP. Importantly the type of pre-study BP meds were also NOT collected
2)Additional BP meds other than the study drugs were able to be prescribed during the study - at the physician's discretion
3)There was no information on the reasons these subjects were prescribed their pre-study meds. The meds could have been for related but different reasons.
4)This is case only study. meaning they studied only the sick people and there was no control group as in a case control study
5) they then answered a different question post hoc!! "What is the optimal first step therapy" which was not the question in the original prospective design. = posthoc reasoning bias. ALLHAT was not designed to test whether diuretic should be the first line drug.
6) Their assumption that hypertension is a risk factor only and not a disease in itself of many causes.
Etc etc etc
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