CHAPTER 5 Conducting Clinical Research 63

»

» ^{Exploratory efficacy objective: To compare the effect of drug XYZ, relative to}

drug ABC, on changes in sexual function from baseline to weeks 4, 8, and 12,

in male and female subsets of participants with HTN.»

» ^{Safety objective: To evaluate the safety of drug XYZ, relative to drug ABC, in}

terms of the occurrence of adverse events, changes from baseline in vital signs

such as temperature and heart rate, and changes in laboratory results of safety

panels (including tests on kidney and liver function), in participants with HTN.

For each of these objectives, it is important to specify the time range of participa-

tion subject to the analysis (such as the first week of the trial compared to other

time segments). Also, which groups are being compared for each objective should

be specified.

Hypotheses usually correspond to the objectives but are worded in a way that

directly relates to the statistical testing to be performed. So, the preceding pri-

mary objective may correspond to the following hypothesis: “The mean 12-week

reduction in SBP will be greater in the XYZ group than in the ABC group.” Alter-

natively, the hypothesis may be expressed in a more formal mathematical nota-

tion and as a null and alternate pair (see Chapters 2 and 3 for details on these

terms and the mathematical notation used):

H

H

Null

XYZ

ABC

Alt

XYZ

ABC

:

:

0

0

where

mean of (SBPWeek 12

Baseline

SBP

).

In all types of human research, identifying the variables to collect in your study

should be straightforward after you’ve selected a study design and enumerated all

the objectives. In a clinical trial, you will need to operationalize the measurements

you need, meaning you will need to find a way to measure each concept specified

in the objectives. Measurements can fall into these categories:»

» ^{Administrative: This information includes data related to recruitment,}

consent, and enrollment, as well as contact information for each participant.

You need to keep track of study eligibility documentation, as well as the date

of each visit, which study activities took place, and final status at end of study

(such as whether participants completed the study, dropped out of the study,

or any other outcome).»

» ^{Intervention-related: This includes data related to the intervention for each}

participant, such as group assignment, dosing level, compliance, and adher-

ence measures. If you plan to assign a participant to a particular group but

they end up in another group, you need to keep track of both group

assignments.