Assessing Trends in Chlamydia Positivity and Gonorrhea Incidence and Their Associations With the Incidence of Pelvic Inflammatory Disease and Ectopic Pregnancy in Washington State, 1988-2010

Abstract

Background: Chlamydia and gonorrhea screening for women is beneficial if it prevents serious reproductive sequelae, such as pelvic inflammatory disease (PID) and ectopic pregnancy (EP). We assessed trends in PID and EP among women in Washington and their association with gonorrhea incidence and chlamydia positivity in a screened population of women over a 23 year period.

Methods: Using data on chlamydia positivity from the Infertility Prevention Project, gonorrhea incidence from state surveillance, and PID and EP hospitalizations from hospital discharge records, we assessed trends in each condition over time. In addition, we estimated total incidence of PID and EP by incorporating information on outpatient-treated cases in alternative populations using a Bayesian approach that accounted for uncertainty in the estimates. We assessed associations between each infection and PID/EP using a linear regression model that accounts for year-to-year correlation in data points.

Results: We observed substantial declines in both infections and in each outcome over time. For every 2% decrease in chlamydia positivity, there was a 35.7/100,000 decrease in estimated total PID incidence (P = 0.058) and 184.4/100,000 decrease in estimated total EP (P = 0.149). For every 32/100,000 decline in gonorrhea incidence, there was a 16.5/100,000 decrease in total PID (P = 0.292) and 159.8/100,000 decrease in total EP (P = 0.020). The associations with inpatient PID and EP were highly significant for both chlamydia and gonorrhea.

Conclusions: These ecological data note concurrent and substantial declines in chlamydia positivity and gonorrhea incidence, and in PID and EP incidence in Washington from 1988 to 2010 during a time when widespread chlamydia screening was ongoing.