Table 4.

Association (HR and 95% CI) of patient-doctor contact frequency with all-cause mortality and first hospitalization, by region

Variable	Overall	North America	Europe/ANZ	Japan
All-cause mortality
PDC frequency
Low frequency (less than weekly)	1.11 (1.01 to 1.23)	1.15 (0.97 to 1.35)	1.06 (0.93 to 1.21)	0.97 (0.68 to 1.39)
Intermediate frequency (weekly)	1.06 (0.96 to 1.17)	1.06 (0.92 to 1.22)	1.04 (0.88 to 1.23)	1.43 (1.10 to 1.85)
High frequency (more than weekly)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)
PDC duration
Per 5 min shorter duration	1.05 (1.01 to 1.09)	1.03 (0.96 to 1.10)	1.07 (1.02 to 1.12)	1.01 (0.85 to 1.20)
First hospitalization
PDC frequency
Low frequency (less than weekly)	1.22 (1.11 to 1.34)	1.30 (1.09 to 1.55)	1.20 (1.05 to 1.37)	1.11 (0.87 to 1.43)
Intermediate frequency (weekly)	1.14 (1.04 to 1.25)	1.23 (1.07 to 1.41)	1.08 (0.90 to 1.29)	1.03 (0.81 to 1.31)
High frequency (more than weekly)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)
PDC duration
Per 5 min shorter duration	1.06 (1.02 to 1.10)	1.06 (0.99 to 1.14)	1.06 (1.01 to 1.11)	0.98 (0.86 to 1.13)

Associations between PDC and both mortality and first hospitalizations were assessed in Cox models (1) overall, stratified by region, and (2) including interaction terms for PDC frequency × region and PDC duration × region to provide region-specific estimates. All Cox models stratified by study phase; accounted for facility clustering effects; and adjusted for age, sex, race, body mass index, 14 comorbid conditions, education, employment and living status, marital status, patient-doctor ratio, patient-staff ratio, hospital-based unit, Kt/V, treatment time, serum albumin, calcium, phosphorus, hemoglobin, and vascular access. Overall model additionally stratified by region. PDC frequency models adjusted for continuous PDC duration, and PDC duration models adjusted for PDC frequency categories. ANZ, Australia/New Zealand.