RT Book, Section
A1 Greenberg, Raymond S.
A1 Daniels, Stephen R.
A1 Flanders, W. Dana
A1 Eley, John William
A1 Boring, John R.
SR Print(0)
ID 545732
T1 Chapter 7. Clinical Trials
T2 Medical Epidemiology, 4e
YR 2005
FD 2005
PB The McGraw-Hill Companies
PP New York, NY
SN 9780071416375
LK accesspharmacy.mhmedical.com/content.aspx?aid=545732
RD 2024/04/18
AB A  clinical  trial  is  the  direct  comparison  of  two  or  more  treatment  modalities  in  human  groups.  Evidence-based  medicine  is  the  integration  of  current  best  evidence  with  clinical  expertise,  pathophysiological  knowledge,  and  patient  preferences  to  make  health  decisions.  The  practice  of  evidence-based  medicine  is  encouraged  because  it  may  lead  to  more  consistent  and  objective  clinical  decisions.  A  type  I  error  occurs  when  a  study  finds  a  difference  in  effectiveness  between  the  treatments  being  compared  when  in  fact  no  difference  exists.  A  type  II  error  occurs  when  a  study  fails  to  find  a  difference  in  treatment  effectiveness  between  the  treatments  being  compared  when  in  fact  a  difference  does  exist.  Statistical  power  is  the  ability  of  a  study  to  detect  a  true  difference  between  groups  being  compared.  When  treatments  are  assigned  by  randomization,  probability  alone  determines  assignment,  rather  than  the  personal  preferences  of  either  physicians  or  patients.  When  patients  are  unaware  of  their  treatment  assignment  in  a  clinical  trial,  it  is  referred  to  as  a  single-blinded  study.  In  a  double-blinded  study,  neither  the  patients  nor  the  treating  physicians  know  individual  treatment  assignments.  A  ratio  of  either  rates  or  risks  can  be  used  to  compare  the  outcomes  in  the  experimental  and  control  groups.  Meta-analysis  is  a  statistical  integration  of  the  results  of  several  independent  studies.  A  sensitivity  analysis  can  be  used  to  determine  whether  differences  across  studies  may  be  explained  by  characteristics  of  the  various  populations  studied.