Objectives: To describe retention according to age and visit type (clinic, home, telephone) and to determine characteristics associated with visit types for a longitudinal epidemiological study in older adults.
Design: Longitudinal cohort study.
Setting: Four U.S. clinical sites.
Participants: Five thousand eight hundred eighty-eight Cardiovascular Health Study (CHS) participants aged 65 to 100 at 1989/90 or 1992/93 enrollment (58.6% female; 15.7% black). CHS participants were contacted every 6 months, with annual assessments through 1999 and in 2005/06 for the All Stars Study visit of the CHS cohort (aged 77-102; 66.5% female; 16.6% black).
Measurements: All annual contacts through 1999 (n=43,772) and for the 2005/06 visit (n=1,942).
Results: CHS had 43,772 total participant contacts from 1989 to 1999: 34,582 clinic visits (79.0%), 2,238 refusals (5.1%), 4,401 telephone visits (10.1%), 1,811 home visits (4.1%), and 740 other types (1.7%). In 2005/06, the All Stars participants of the CHS cohort had 36.6% clinic, 22.3% home, and 41.1% telephone visits. Compared with participants aged 65 to 69, odds ratios of not attending a CHS clinic visit were 1.82 (95% confidence interval (CI)=1.54-2.13), 2.94 (95% CI=2.45-3.57), 4.55 (95% CI=3.70-5.56), and 9.09 (95% CI=7.69-11.11) for those aged 70 to 74, 75 to 79, 80 to 84, and 85 and older, respectively, in sex-adjusted regression. In multivariable regression, participants with a 2005/06 clinic visit were younger, more likely to be male and in good health, and had had better cognitive and physical function 7 years earlier than participants with other visit types. Participants with home, telephone, and missing visits were similar on characteristics measured 7 years earlier.
Conclusion: Offering home, telephone, and proxy visits are essential to optimizing follow-up of aging cohorts. Home visits increased in-person retention from 36.5% to 58.8% and diversified the cohort with respect to age, health, and physical functioning.