Table 1

Characteristics of Analytic Subcohorts for Each Outcome

CharacteristicInpatient Admissions Emergency Department Visits
Primary Care a (n = 8,863) Mean (SD)Specialty Carea (n = 6,724) Mean (SD)Primary and Specialty Carea (n = 5,660) Mean (SD)Primary Carea (n = 8,706) Mean (SD)Specialty Carea (n = 6,738) Mean (SD)Primary and Specialty Carea (n = 5,713) Mean (SD)
Age, y76.0 (6.0)75.8 (5.9)76.0 (5.9)75.9 (6.0)75.8 (5.8)76.0 (5.8)
Morbidity burdenb4.3 (2.4)4.4 (2.5)4.4 (2.5)4.3 (2.5)4.5 (2.5)4.5 (2.5)
Baseline visits, No.
 Primary care3.8 (2.8)3.8 (2.8)4.0 (2.9)3.7 (2.8)3.7 (2.8)3.9 (2.8)
 Specialty care3.2 (3.6)4.1 (3.9)4.1 (4.0)3.3 (3.7)4.1 (4.0)4.1 (4.0)
COCIc
 Primary care0.6 (0.3)0.6 (0.3)0.6 (0.3)0.6 (0.3)
 Specialty care0.2 (0.2)0.2 (0.2)0.2 (0.2)0.2 (0.2)
PercentPercentPercentPercentPercentPercent
Female sex56.455.055.455.654.254.2
Race/ethnicity
 White78.880.881.079.181.181.2
 Black4.44.14.04.23.93.8
 Hispanic10.59.29.410.39.19.4
 Other1.81.71.61.81.71.7
 Unknown4.64.23.94.54.23.9
Low socioeconomic status15.414.314.215.014.213.8
Baseline utilization
 Inpatient admissions16.918.718.7
 Emergency department visits17.017.517.8
Experienced any outcomed21.722.820.622.923.420.4
  • COCI = Continuity of Care Index.27

  • a Three visits required for subcohort entry.

  • b According to the Quan-adapted Elixhauser comorbidity index.28

  • c Last measured before outcome or censoring. Possible values range from 0 to 1 with higher scores indicating greater continuity.

  • d Hospital admission or emergency department visit.