Missed Opportunities for Chlamydia Testing: A Look Into (non)Overlapping Clinical and Public Health Data

Background: Approximately half of sexually active young women receive annual chlamydia screening, an important HEDIS measure of health care quality.  However, the number of eligible women whose sexual activity status is not ascertained (and are therefore not screened) is unknown. One approach to study this unscreened population is to use alternative data to identify women diagnosed with chlamydia in settings outside her primary healthcare system.     

Objectives: Determine how many young women in a large clinical system who have no identified HEDIS criteria for sexual activity have a chlamydia diagnosis in the local public health data.

Methods: Retrospective longitudinal cohort study of 14-25 year old women between 1998-2007 with at least 1 routine, outpatient clinical visit in a non-specialty setting (N=61,379 subjects). Sexual activity was established by electronic medical record (EMR) evidence of sexual activity according to HEDIS criteria. Comparison data on chlamydia diagnosis was obtained from the local public health (PH) data for the same time period, matching by patient name and birth date. All eligible women identified in the EMR were classified according to prior evidence of sexual activity, EMR chlamydia test and diagnosis, and PH chlamydia diagnosis.

Results: During the study period, 20.7% of young women were diagnosed with chlamydia either within the EMR or PH system (13.0% within the EMR and 17.0% within the PH system). Among women with no evidence of sexual activity based on HEDIS criteria, 4.9% had a prior diagnosis of chlamydia within the PH system. 

Conclusions: Because some chlamydia tests and diagnoses occur outside the health care system, the number of sexually active young women is underestimated and, hence, rate of chlamydia testing is likely overestimated by HEDIS measures.

Implications for Programs, Policy, and/or Research: By supplementing clinical data with public health data, we may better define measures of health care quality and may enable clinicians to identify women inappropriately not screened for chlamydia.