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October 1996

Methodological Issues in Determining Rates of Childhood Immunization in Office PracticeA Study From Pediatric Research in Office Settings (PROS)

Author Affiliations

From the Department of Pediatrics, Medical University of South Carolina, Charleston (Drs Darden and Recknor); Department of Pediatrics, University of Washington School of Medicine, Seattle (Dr Taylor); Pediatric Research in Office Settings (PROS), American Academy of Pediatrics, Elk Grove Village, Ill (Drs Slora and Wasserman and Mss Hasemeier and Asmussen); and Department of Pediatrics, University of Vermont College of Medicine, Burlington (Dr Wasserman).

Arch Pediatr Adolesc Med. 1996;150(10):1027-1031. doi:10.1001/archpedi.1996.02170350029004

Objective:  To compare 3 methods for measuring pediatric office immunization rates.

Design:  Retrospective and prospective cross-sectional surveys.

Patients:  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.Arch Pediatr Adolesc Med. 1996;150:1027-1031