Table 3.

Factors Associated with Emergency Department Visits for Asthma Using Cox Models (n = 3395)

VariablesCrude ModelAdjusted model
HR95% CIHR95% CI
    1 (Reference)1.001.00
Patient characteristics at baseline
        Female (reference)1.001.00
    Age (years)1.000.97–1.030.980.95–1.01
    Insurance premium (US$)
        <667 (Reference)1.001.00
    P4P participating status
        Not participating (reference)1.001.00
Medical conditions
    In a previous year
            0 (Reference)1.001.00
        No (reference)
In the COC period
    Ambulatory visits for asthma, n
        4–12 (Reference)1.001.00
    Hospitalization for asthma
        No (reference)1.001.00
    ED visits for asthma
        No (reference)1.001.00
  • CCI, Charlson Comorbidity Index; CI, confidence interval; COCI, continuity of care index; COPD, chronic obstructive pulmonary disease; ED, emergency department; HR, hazard ratio; P4P, pay for performance.