Table 3.

Association (HR and 95% CI) of PDC Frequency and Duration with All-Cause Mortality, after Various Levels of Adjustment

All-Cause Mortality	Model 0	Model 1	Model 2	Model 3	Model 4	Model 4a	Model 4b
PDC frequency
Low frequency (less than weekly)	1.08 (0.99 to 1.19)	1.11 (1.01 to 1.22)	1.11 (1.01 to 1.23)	1.11 (1.01 to 1.22)	1.08 (0.98 to 1.19)	1.11 (1.01 to 1.23)
Intermediate frequency (weekly)	1.10 (1.00 to 1.21)	1.07 (0.97 to 1.19)	1.08 (0.97 to 1.19)	1.07 (0.97 to 1.18)	1.06 (0.96 to 1.16)	1.06 (0.96 to 1.17)
High frequency (more than weekly)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)
P for trend across categories	0.07	0.04	0.02	0.04	0.11	0.03
PDC duration
Per 5 min shorter duration	1.08 (1.04 to 1.12)	1.04 (1.00 to 1.08)	1.04 (1.00 to 1.08)	1.05 (1.01 to 1.09)	1.04 (1.01 to 1.08)		1.05 (1.01 to 1.09)
P for duration as continuous variable	<0.001	0.03	0.03	0.02	0.03		0.01
Categorical analysis
Short duration (≤5 min)	1.23 (1.10 to 1.38)	1.11 (1.00 to 1.24)	1.11 (0.99 to 1.24)	1.12 (1.00 to 1.25)	1.11 (0.99 to 1.24)		1.13 (1.01 to 1.27)
Intermediate duration (6–10 min)	1.17 (1.03 to 1.32)	1.10 (0.98 to 1.24)	1.10 (0.98 to 1.24)	1.09 (0.97 to 1.23)	1.11 (0.99 to 1.25)		1.13 (1.00 to 1.28)
Long duration (>10 min)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)		1.00 (reference)

Model 0: stratified by phase and region and accounted for facility clustering effects; model 1: model 0 + age, sex, race, body mass index, dialysis vintage, and 14 comorbid conditions; model 2: model 1 + education, employment and living status, marital status; model 3: model 2 + patient-doctor ratio, patient-staff ratio, and hospital-based units; model 4: model 3 + Kt/V, treatment time, serum albumin, calcium, phosphorus, hemoglobin, and vascular access; model 4a: model 4 + PDC duration (continuous); model 4b: model 4 + PDC frequency (categories).