Fig 1.
A scheme of the applied contract strategies.
Fig 1 outlines the predefined contact schedule for the ‘direct contact’ (contact strategy 1) and the ‘arranged contact’ (contact strategy 2) group.
Fig 2.
The CONSORT diagram shows the patient flow through the study including trial and external validation.
Table 1.
Baseline characteristics as well as trial and validation outcomes.
Fig 3.
Fig 3 shows cumulative Kaplan Meier estimates of the proportion of successful interviews over time. Data are stratified for the three groups: strategy 1 versus strategy 2 versus validation of strategy 1. The vertical dashed orange line marks the allowed pre-set latency of 16 days in the ‚arranged contact’ group (contact strategy 2) to await participants’ responses. The ‘direct contact’ strategy (contact strategy 1) succeeded with a shorter median duration to successful interview and was then re-evaluated in the validation group showing a similar duration to successful interview.