Table 2.

Predictors of time to participant contact

	Interim model			Final model
	HR	(95% CI)	p-value	HR	(95% CI)	p-value
Patient factors
Enrolled from the primary study site	1.45	(0.84-2.50)	(0.20)	1.32	(0.76-2.28)	0.32
Employed€	0.53	(0.19-1.50)	(0.27)
Type of work€
Non-physical labor	1.54	(0.46-5.12)	(0.48)
Physical labor, not working or unemployed	Ref
Patient-reported chronic fatigue*	1.55	(0.91-2.62)	(0.10)	1.85	(1.12-3.06)	0.02
Requires assistance at home€	1.28	(0.67-2.41)	(0.44)
Lives in a health care facility€	0.50	(0.20-1.27)	(0.15)	0.57	(0.23-1.43)	0.23
Research visit factors
Number of contact phone numbers available	1.04	(0.91-1.18)	(0.51)
Visit in clinic	1.05	(0.60-1.84)	(0.88)
Last visit not conducted in clinical due to patient illness/condition	0.45	(0.20-1.01)	(0.05)	0.40	(0.19-0.84)	0.02
Incomplete data collection due to personal factors£	0.88	(0.48-1.61)	(0.71)
Missed last follow-up visit	1.22	(0.33-4.45)	(0.47)
Missed visit due to personal factor$	0.67	(0.16-2.71)	(0.38)
Ever missed any follow-up visit	0.73	(0.31-1.72)	(0.26)

Abbreviations: HR: hazard ratio, >1 indicates a shorter time to contact with the participant; CI confidence interval

^*Missing data for 1 patient.

^£Patient incarcerated, on ventilator, excessively fatigued, cognitively, mentally or, physically incapable.

^$Patient incarcerated, refusal-not interested, no time or too much stress, drug or alcohol influence.

^€Measured at last follow-up visit; due to collinearity “physical labor” category was combined with “not working or unemployed”