11-28-2007, 09:40 AM
A 1-year study of a new drug to treat hypertension is conducted.
One hundred patients with hypertension are enrolled; 50 patients are
given the new drug and another 50 patients are given
hydrochlorothiazide. All patients completed the trial. One noted
unexpected effect is increased growth of scalp hair which occurred in
those taking the new drug, a nonstatistically significant difference
(p>0.10). This effect has also been reported in studies of other
similar drugs in the new therapeutic class. The investigators of the
study concluded that the new drug did not cause hair growth. Which of
the following features of this study is most likely to affect the
validity of this conclusion?
A
) Differential follow-up
B
) Lead time bias
C
) Length of the study
D
) Sample size
E
) Self-selection
One hundred patients with hypertension are enrolled; 50 patients are
given the new drug and another 50 patients are given
hydrochlorothiazide. All patients completed the trial. One noted
unexpected effect is increased growth of scalp hair which occurred in
those taking the new drug, a nonstatistically significant difference
(p>0.10). This effect has also been reported in studies of other
similar drugs in the new therapeutic class. The investigators of the
study concluded that the new drug did not cause hair growth. Which of
the following features of this study is most likely to affect the
validity of this conclusion?
A
) Differential follow-up
B
) Lead time bias
C
) Length of the study
D
) Sample size
E
) Self-selection