KEYWORD1:
Vaccination coverage; immunization registry; assessment method

BACKGROUND:
Immunization assessments using predetermined audit dates tend to underestimate coverage because they include patients no longer active in the practice. Assessments at the time of the last visit to the practice offer providers complementary perspectives on immunization status. Immunization registries can be used to conduct practice assessments with flexible points of assessment. In 2000, we launched a registry at a network of practices in a low-income community in New York City.

OBJECTIVE:
To compare registry-based practice coverage at the time of the last patient encounter with coverage at a predetermined audit date.

METHOD:
We conducted registry-based practice assessments at 5 NYC practices. We included all children 6-23 months of age with at least one visit to the practice (n = 4,725). We compared coverage at the last visit with coverage in April 2002. The outcome measurement was age-appropriate immunization rates for DTaP, Polio, MMR, Hib, and HepB (4:3:1:3:3).

RESULT:
The differences between coverage rates were statistically significant for all ages. For children 6-11 months old, coverage at a predetermined date was 48.1%, while it was 78.3% at time of last visit, a difference of 30.2% (p <.001). For 12-23 months old, the coverage rate was 39.5% and 70.6%, respectively, a difference of 31.1% (p<.001).

CONCLUSION:
The immunization registry facilitates calculation of coverage rates with different date criteria. The coverage difference for the same children suggests areas for practice improvement, namely to minimize disengagement and subsequent record scatter.
LEARNINGOBJECTIVES:
Methodology for immunization registry quality improvement.