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Fig. 2 | BMC Medical Research Methodology

Fig. 2

From: New methods for estimating follow-up rates in cohort studies

Fig. 2

Illustration of the Reverse Kaplan-Meier Survival Curve for follow-up rate. The figure depicts a hypothetical cohort of 100 subjects who were followed for two years, there were 30 outcome events in the 1st year in scenario (A) and 10 outcome events in the 1st year in scenario (B) while in both scenarios there was no dropout in the 1st year and 30 dropouts in the 2nd year. The dashed dotted line describes the reverse KM follow-up rate for scenario (A), the dashed line describes the reverse KM follow-up rate for scenario (B) and the solid line describes the follow-up rate after treating outcome events as competing events. While scenario (A) and (B) have the exactly the same level and timing of dropouts, scenario (A) has a lower follow-up rate simply because it has more earlier events; both scenarios share the same follow-up rate after addressing competing risk. Note: this is not the KM curve for the outcome events. In this plot, losses to follow-up were treated as “events” while development of outcome events were treated as “censored”

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