04-26-2009, 09:54 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
A
) Differential follow-up
B
) Lead time bias
C
) Length of the study
D
) Sample size
E
) Self-selection