Prevention of Attrition Keys to Successful Cohort Maintenance Patricia B. Crawford, DrPH, RD Adjunct...
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Transcript of Prevention of Attrition Keys to Successful Cohort Maintenance Patricia B. Crawford, DrPH, RD Adjunct...
Prevention of AttritionKeys to Successful Cohort Maintenance
Patricia B. Crawford, DrPH, RDAdjunct Professor
Co-Director, Center for Weight and Health
University of California, Berkeley
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Mission
Provide leadership for the development of interdisciplinary, science-based solutions to body weight- and health-related problems, with a current focus on the prevention of pediatric overweight
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http://www.cnr.berkeley.edu/cwh
• Literature reviews and synthesis
• School-based intervention studies
• Resources and materials for communities
• Conducting and translating epidemiologic studies
• Community-based intervention studies
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http://www.cnr.berkeley.edu/cwh
Berkeley
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San Francisco
Berkeley Longitudinal Nutrition Study (BLNS)
Aim: To examine the development of childhood obesity from birth to 5 years
Design: Longitudinal study
Measurements: Anthropometry, food and activity records and interviews, lipid profiles, underwater weighing.
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Berkeley Longitudinal Nutrition Study Retention
Year Visit Participants (n)
1969 6 months 450
1970 1 year 386
1971 2 years 312
1972 3 years 270
1973 4 years 242
1975 6 years 186
1985 16 years 180c enter fo r
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1980’s
Overweight among black women was significantly higher than among white women and they experienced higher CVD mortality rates.
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NHLBI Growth & Health Study (NGHS)1987-1992
(funded by National Institute of Heart, Lung & Blood, NIH)
Aim: to track the development of obesity and other cardiovascular risk factors and to identify biological, social and psychological correlates of these risk factors.
Measurements: diet, physical activity, anthropometry, self esteem and other psychosocial factors, blood pressure, lipids, glucose, insulin, health beliefs and attitudes, and family environment measures
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General Description of NGHS
• Design: – Prospective multi-site
biracial cohort study• Subjects: 2379 girls
– 1213 black– 1166 white
• Ages: 9-10 years at baseline
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Locations
• Richmond, California
• Cincinnati, Ohio
• Washington, DC area
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Berkeley
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San Francisco
Richmond
Richmond, California*
• Population: ~100,000
• 16% of the population below poverty line
• High unemployment approaching 10%
• Over 1,000 violent crimes/year
*statistics from 2003-2006c enter fo reight &
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Recruitment Strategies• Richmond: census sample of girls
enrolled in schools encompassed
by Richmond Unified School District• Cincinnati: Sampled at school level• Washington, DC area: random sampling of HMO
members with a few added volunteers.
Year Age
Retention Rate (%)
Richmond (n=887)
Cincinnati (n=871)
Wash. DC (n=621)
Total (n=2379)
1 9 to 10 100 100 100 100
3 11 to 12 93.1 92.4 96.3 93.7
5 13 to 14 85.9 83.1 91.8 86.4
7 15 to 16 85.2 77.4 83.9 82
9 17 to 18 93.3 80.9 88.6 87.6
10 18 to 19 93 81 90 88
NGHS Retention Rates by site
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Richmond Cincinnati Wash. DC
Refused 1.3 9.1 4.7
Not responsive 0.7 3.6 3.1
Not located 2.5 4.5 0.2
Distance 1.7 1.7 1.1
Other 0.5 0.2 2.4
Total not seen 6.7 19.1 11.5
Percentage of girls not seen by reason by site
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Minimizing Attrition
• External validity
• Internal validity
• Statistical power
Prevention of Attrition
• Recruitment strategies
• Traditional retention strategies
• Key to success: enhanced strategies
Traditional Strategies – to Prevent Attrition
Communication (7)
Phone calls; directory assistance
Letter; mail forwarding or certified mail
Family and friend contacts
Tracking (5)Private investigators, police department, social services, post office, driver's licenses, employment records, job, school, hospital and online databases
Incentives (4) Cash, gifts, lottery, raffles
Special Methods (1)
Send birthday cards, check in often, organize events for participants
Educate participants
Provide transportation
StaffCharacteristics (1)
Health promotion skills and knowledge and continuity of staffRefs: Aylward 1985; Goldman 1982; Gwadz 1992; Katz 2001; Lloyd 1999; Orr 1992; Pirie 1989; Psaty 1994; Senturia 1998
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CommunicationIncentives
Special Methods
Staff Characteristics
Tracking
Traditional Strategies to
Prevent Attrition
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Incentives Communication
Special Methods
Staff Characteristics
TrackingDevelop refusal
conversion system
Pilot test
Communicate values,
expectations, plans, etc.
Develop comprehensive
tracking system
Keys to Success
Hire culturally sensitive, respectful,
flexible staffc enter fo reight &
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1. Staff Hiring
• Culturally sensitive• Flexible• Respectful• “Customer” is always right
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2. Development of Tracking Systems
• Annual update and expansion of contact information
• Call records• Hire a sleuth, problem
solving, obsessive-compulsive interviewer
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_________________________________________________TRADITIONAL CALL RECORD for Participant 1181 – Luann Stipes_________________________________________________
1/9/98 — No answer.1/10/98 — No answer.1/12/98 — Called parents. No answer.1/14/98 — Called parents. Wrong number.
Called mother-in-law who said Luann has moved back Antioch. Her phone number there is (555) 573-2730.
1/15/98 — Called Luann. No answer.1/16/98 — Reached Luann and scheduled her for Saturday,
Jan. 27th at 11 am. Need to mail directions and date/time of appointment.
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CALL RECORD for Alicia Green 400 39th St., Richmond, CA 94804 -(510) 777-5010
3/4/98—1:35 pm—666-7777 is disconnected.Tried father at (510) 888-9999. Left no message on answering machine.5:40 pm—Called father’s number and reached Alicia’s brother. She does nothave a phone, can be reached through this number. He said he’d relay a message. He said she can be reached at this number between 1 and 3 pm. I told him I’d try tomorrow. He said he’d relay the message.
3/5/98—1:00 pm--busy signal1:20 pm—Reached Alicia. She is living with Dad and about to move into her own house. Seemed pleased to hear from me. Cooperative. busy now, but call next week.
3/12/98—1:30 pm—Answering machine, did not leave message3/13/98 - 4:00 pm—Reached brother. Alicia has moved to own place. Got her phone number, 111-2222. Number is not in service.3/14/98—7:00 pm—Tried Alicia’s number again. Still not in service. Called brother; reached
father this time. He doesn’t have number for Alicia. Also says he doesn’t have her new address. Says I can call tomorrow morning at 10:00 am.
3/15/98—10:05 am—Reached brother. Alicia does not have a phone. Gave me her address: 2121 5th Street in Richmond. Sent Alicia a note with my phone number, asking her to call me.3/29/98—6:00 pm—Went to Alicia’s address. She was home and very happy to hear from us
again. Scheduled her for clinic on 4/7 at 11:00 am. She is happy to have her own place, lives with her son. 4/7/98—Alicia came to clinic. Everything went well. Really cute little boy, named DeVonne.
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3. Pilot Testing
4. Development of a Refusal Conversion System
• Hire/designate a specialist
• Use all information from past call records
• Take participants’ reservations seriously
• Minimize number of contacts
• Take the long view on participation
• Empathize, listen
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5. Communication
• Plan for retention, revise as needed
• Share what works
• Values, study goals, results
• High expectations
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Incentives Communication
Special Methods
Staff Characteristics
TrackingDevelop refusal
conversion system
Pilot test
Communicate values,
expectations, plans, etc.
Develop comprehensive
tracking system
Key to success:
leadership
Hire culturally sensitive, respectful,
flexible staffc enter fo reight &
ealthh University of California, Berkeley
Study Leadership
• Plan and budget recruitment, tracking, cohort retention, refusal conversion
• Hire culturally sensitive interviewers with excellent communication skills
• Designate (or hire) specialized tracker and refusal converter staff
• Develop protocols and train staff
• Communicate with staff your values including respect, flexibility, and high expectations
• Celebrate every participant victory
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Using these methods ...Race White Black
NS 87% 88%
Site Richmond CincinnatiWashington
DC
p<.001 93% 81% 90%
Household Income Low Middle Upper
p<.01 85% 89% 90%
BMI Mean for those retained 18.58
NS Mean for those lost to follow-up 18.51c enter fo r
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Comparison of subjects retained and lost (Year 10)
NGHS Follow-up Studies
Follow-up Study Site
End Date
Original Cohort
Follow-up
Retention Rate
Fibromylagia and TMD Berkeley 1989 887 830 94%
Eating Disorders All sites 2001 2379 2046 86%
Pregnancy Berkeley 2003 330 301 91%
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We streamlined the human subjects protection forms by
using handwritten coversheets:Streamline the
human subjects protection forms by using handwritten
coversheets
In order for your child to participate in the Growth and Health Study this year, you must sign the green consent form and return it to your child’s school before Thursday, October 15th.
Thank you, Pat Crawford
Project Directorc enter fo r
eight &ealthh University of California, Berkeley
Our blooper:
Streamline the human subjects
protection forms by using handwritten
coversheets
I order for your child to participate in the Growth and Health Study this year, you must sign the green consent form and return it to your child’s school before Thursday, October 15th.
Thank you, Pat Crawford
Project Directorc enter fo r
eight &ealthh University of California, Berkeley
Thank you
Sheila Stern
Sarah Krathwohl
Zak Sabry
NHLBI
and all of the NGHS participants who have given generously of their time for almost 15 years!
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Visit the Center for Weight and Health at http://www.cnr.berkeley.edu/cwh/