Maximising retention in a longitudinal cohort study

January 01, 0001

Maximising retention in a longitudinal cohort study

Cohort studies are an important study design however they are difficult to implement, often suffer from poor retention, low participation and bias. The aims of this paper are to describe the methods used to recruit and retain young women in a longitudinal study and to explore factors associated with loss to follow up. The Chlamydia Incidence and Re- infection Rates Study (CIRIS) was a longitudinal study of Australian women aged 16 to 25 years recruited from primary health care clinics. They were followed up via the post at three- monthly intervals and required to return questionnaires and self collected vaginal swabs for chlamydia testing.

The study recruited 66% of eligible women. Despite the nature of the study (sexual health) and the mobility of the women (35% moved address at least once), 79% of the women completed the final stage of the study after 12 months. Loss to follow up bias was associated with lower education level (adjusted hazard ratio, AHR, 0.7) recruitment from a sexual health centre as opposed to a general practice clinic and previously testing positive for chlamydia (AHR: 0.8). No other factors such as age, numbers of sexual partners were associated with loss to follow up.

The researchers concluded: "The methods used were considered effective for recruiting and retaining women in the study. Further research is needed to improve participation from less well-educated women."

Research on research is a fascinating area to improve relevance of outcomes.

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BMC Public Health published online 9 March 2011
© 1999-2011 BioMed Central Ltd
Maximising retention in a longitudinal study of genital Chlamydia trachomatis among young women in Australia. Jennifer Walker , Christopher K Fairley , Eve Urban et al. Correspondence to Jennifer Walker: [email protected]

Category: HSR. Health Services Research. Keywords: retention, cohort study, Chlamydia trachomatis, longitudinal study, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 1 April 2011

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