We verify the effectiveness of the proposed model on a real clinical dataset containing 12,120 patient traces, which pertain to the unstable angina CP.
Patient tracing involved phone calls and, if necessary, home visits.
Also, there was no mechanism for pre-ART patient tracing.
Kaplan-Meier plots were used to present 1-year survival estimates before and after patient tracing.
Another limitation relates to the fact that approximately 5% of patients remained lost to follow-up despite patient tracing.
Patient tracing resulted in reporting of a significantly lower estimate of survival than was observed before tracing [log rank P<0.001, Figure 1].
Due to the retrospective nature of patient identification, patient tracing was performed at variable time intervals after a patient's last clinic visit.
Each successive round of patient tracing located a larger proportion of patients and resulted in progressively higher one-year mortality estimates.
Patient tracing significantly increased the number of reported deaths [29 of 410 (7.1%) vs. 69 of 410 (16.8%); P<0.001 for difference in proportion reported dead].
Risk factors for death before and after patient tracing were evaluated using Cox proportional hazards models after testing the validity of the proportional hazards assumption[6], [8].
