Methodological issues in determining rates of childhood immunization in office practice. A study from pediatric research in office settings (PROS).
OBJECTIVE
To compare 3 methods for measuring pediatric office immunization rates.


METHODS
Retrospective and prospective cross-sectional surveys.


METHODS
Children 2 and 3 years old from 15 pediatric practices in 11 states.


METHODS
Immunization rates were determined for each practice using 3 methods. The Consecutive method used data from the practice's medical records of patients seen consecutively in the office; the Chart method used data from randomly selected practice medical records; and the Active method (reference standard) used a combination of medical record data with a telephone interview to collect additional immunization data and current patient status, using data only on current patients. Analyses were based on a mean of 57, 62, and 51 (Consecutive, Chart, and Active method, respectively) patients per practice. Patients were considered fully immunized if they had received 4 doses of DTP/DT vaccine, 3 doses of OPV/IPV, and 1 dose of MMR vaccine by their second birthday Comparisons were made using the paired t test.


RESULTS
The mean immunization rate by method was Consecutive, 81.5% (range, 51%-97%); Chart, 71.6% (range, 42%-94%); and Active, 79.6% (range, 53%-96%). Within a given practice, the differences between methods varied considerably (0 to 28 percentage points). The mean difference from the reference standard Active method was 8 percentage points (P < .001) for the Chart method and -1.9 percentage points (P = .36) for the Consecutive method. The largest difference was between the Consecutive and Chart methods (mean difference, 9.9 percentage points; P = .003). Practitioners uniformly found the Consecutive method easiest to implement.


CONCLUSIONS
Practice-specific immunization rates are one of the few objective measures of the quality of preventive pediatric care. Pediatric practices monitoring their immunization rates should consider using the Consecutive method, a simple, acceptable, and valid measure of practice immunization rate.
Darden
P M
PM
Department of Pediatrics, Medical University of South Carolina, Charleston, USA.
Taylor
J A
JA
Slora
E J
EJ
Hasemeier
C M
CM
Asmussen
L
L
Recknor
J C
JC
Wasserman
R C
RC
D002648:Child; D003430:Cross-Sectional Studies; D004165:Diphtheria / Q000517:prevention & control*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000627:therapeutic use*; D001330:Electronic Data Processing; D006801:Humans; D007115:Immunization Schedule; D010372:Pediatrics; D011446:Prospective Studies; D011897:Random Allocation; D012189:Retrospective Studies; D013742:Tetanus / Q000517:prevention & control*; D014917:Whooping Cough / Q000517:prevention & control*
D015721:Diphtheria-Tetanus-Pertussis Vaccine