Using poisson regression to compare rates of unsatisfactory pap smears among gynecologists and to evaluate a performance improvement plan

Acta Cytol. Mar-Apr 2009;53(2):160-4. doi: 10.1159/000325118.


Objective: To evaluate impact of a performance improvement (PI) plan implemented after initial analysis, comparing 7 gynecologists working in 2 clinics.

Study design: From January to October 2005, unsatisfactory rates for gynecologists and clinics were calculated. A PI plan was instituted at the end of the first quarter of 2006. Unsatisfactory rates for each quarter of 2006 and the first quarter of 2007 were calculated. Poisson regression analyzed results. A total of 100 ThinPrep Pap smears initially deemed unsatisfactory underwent reprocessing and revaluation.

Results: The study's first part evaluated 2890 smears. Clinic unsatisfactory rates, 2.7% and 2.6%, were similar (p > 0.05). Gynecologists' unsatisfactory rates were 4.8-0.6%; differences between each of the highest 2 and lowest rates were significant (p < 0.05). The study's second part evaluated 13,453 smears. Unsatisfactory rates by quarter were 1.76%, 0.67%, 0.38%, 0.70% and 0.76%; the first quarter's rate was higher than in other quarters. For the study's third part, 13 of 100 reprocessed smears remained unsatisfactory.

Conclusion: Gynecologists' unsatisfactory rates can differ. Analyzing differences can result in quality improvement. Reprocessing ThinPrep smears is an important means of reducing unsatisfactory rates but should not be a substitute for attention to quality in sampling.

Publication types

  • Comparative Study

MeSH terms

  • Education, Medical, Continuing / methods*
  • Female
  • Gynecology / standards*
  • Humans
  • Mass Screening / methods
  • Mass Screening / standards
  • Papanicolaou Test*
  • Physicians
  • Poisson Distribution
  • Uterine Cervical Neoplasms / diagnosis
  • Vaginal Smears / methods
  • Vaginal Smears / standards*