Transcript RCT`s and exercise

RCT’s and exercise
Terra C Murray
Background
We know that physical activity is good for
people, especially at the population level
But what are the outcomes of walking 10 000
steps everyday?
How does this compare to more traditional types
of physical activity or exercise?
one question:
What are the outcomes associated with different
‘types’ of physical activity?
population?
Activity?
Measures?
• Physiological, psychological…..
Design of study
Health First research study
what’s in a name……
“Couch Potato” study
Funding source: CIHR
The “team”
PI (Dr. Rodgers) and then Co-I’s (Drs. Bell,
Courneya and Harber).
RA’s: in the trenches (Murray, Loitz, Scime,
Wild…)
Assistants (Johnston); Consultants (Fraser);
Paid help/contracted work (SPU, DKML);
Practicum students
Study design
What is the best way to answer the question?
Randomized Clinical Trial
O1 R T1 O2 O 3
O1 R T2 O2 O 3
O1 R
O2 O 3
R provides a time point when the groups start to diverge
in ways that might be unpredictable (LaValley, 2003)
Intention to Treat Analysis
Typically RCT’s use ITT analysis
Includes all randomized participants, regardless of
adherence, treatment, withdrawal, or deviation from
protocol
Pragmatic vs Explanatory Hypotheses
Pragmatic: identify the utility or effectiveness of treatment
Explanatory: isolate and identify biologic effects – often need to
exclude noncompliant participants from analysis
LaValley, 2003
6 months of activity + about 1 month for pre and
post measures
Target N = 226
Population: sedentary men and women
Measures: fitness, blood lipid and glucose, HR, BP,
body comp., attitudes to exercise, social support,
self-efficacy …….
Groups or treatment arms:
Blue: traditional fitness center based CV program
Yellow: lifestyle walking program – 10 000 steps
Red: daily maintenance (control)
$$$$$$$$
Pedometers, HR monitors, blood pressure cuffs,
blood measures, freezer to store blood,
physiological tests, photocopying, mailing, tshirts, water bottles, computer, research
assistants ……………..
“I lost my pedometer….”
recruitment
Who and how?
Sedentary but “healthy”
volunteers
Inclusion and exclusion criteria
High BP, too active, diabetic, 25-65, Dr. says no
Often changes or alters
Randomization and Rx
After all pre-measures, randomization is
performed and participants are notified
Challenges
Control group
Fit Center Group
Walking Group
Issues in RCT and exercise
Don’t like your group
Assigned to a control group
Friends, partners/spouses…..
Intention to Treat analysis
Don’t comply with the “prescription”
Do not complete the trial (we have no post
measure)
Minimize withdrawal and
noncompliance
Cannot impact the integrity of study or the
“question”
Weekly contact with all participants
Solicit their advice, ask how things are going
Incentives during trial
Incentives when trial is completed