Descriptive Characteristics and Chlamydia (CT) Testing in a Cohort of Women with Ectopic Pregnancy in An Urban Healthcare System

Background: Ectopic pregnancy (EP) can result from tubal injury due to sexually transmitted CT infections. Higher number of CT diagnoses increases EP risk. To guide screening strategies, studies are needed to distinguish number of CT infections from cumulative duration of untreated infection as major drivers of EP.

Objectives: An electronic medical record (EMR) system serving an urban healthcare system in Indianapolis was used to identify a cohort of women with EP diagnosis to establish feasibility of examining relative roles of CT infection frequency and duration to EP risk.

Methods: The Regenstrief EMR was searched by ICD-9 codes for first EP diagnosis (1993 to 2009). First and subsequent CT tests prior to EP, subject age, race and treatments were documented. Risk interval is the interval between first CT test and EP; cumulative infection duration after diagnosis was defined as time(s) between positive CT test(s) and either treatment(s) or negative subsequent test(s).

Results: 2185 individuals had EP diagnosis (median age 26 y); 53.4% black, 8.9% Hispanic, 34.8% white. Highest EP occurrence was in ages 20-24 y (33%) and 25-29 y (28.5%). 1292 (59.1%) individuals had >1 CT test prior to EP; the number of CT tests varied (mean 6.1 +/- 6.4, median=4) during a median risk interval of 4.05 y. Median age of first CT test was 19.8 y; 67.4% had no positive CT tests; 19.4% had 1, 6.9% 2 and 6.4% >3 positive tests.  Cumulative infection duration was <30 days in 47.5% and 30-180 days in 25.2%.

Conclusions: In a large cohort of women with EP, a substantial subgroup with pre-EP CT tests are available to examine risk associated with CT infection duration and number of infections.

Implications for Programs, Policy, and Research: Large retrospective cohorts such as described here, coupled with appropriate control groups, could help define characteristics of CT infection associated with EP.