The Association Between Disease Investigator Specialist (DIS) Interview and 1-Year Re-Infection Rates for Clients Recently Diagnosed with Gonorrhea in Los Angeles County

Background:  Although partner services (PS) is the primary public health strategy used to interrupt ongoing transmission of STDs, there are limited assessments of its impact on re-infection.  To better understand the utility of PS in an era of increasing morbidity and declining STD control resources, we examined the association between Disease Investigator Specialist (DIS) interviews for gonorrhea and 1-year re-infection.

Methods:  Using surveillance data, the records of all gonorrhea cases with documented treatment that were reported in Los Angeles County (LAC) in 2013 (n=11,832) were classified according to whether they were interviewed at the reporting facility, by phone, in the field, or not assigned for interview.  Cases who were assigned for investigation but not interviewed, moved out of LAC, or were deceased were excluded from the analysis (n=4,176). Multivariate logistic regression models were used to test the association between DIS interview and re-infection within 14 to 365 days after the original specimen collection date.

Results: Among males, the proportion of clients with a re-infection by type of interview was: 18.8% (not assigned), 17.5% (interviewed at the reporting facility), 13.4% (interviewed by phone), and 9.1% (interviewed in the field) (p<0.001).  Among females, the corresponding numbers were 4.6%, 6.6%, 5.3%, and 7.0% (p=0.55), respectively.  In multivariate models that controlled for demographics, males who were interviewed by phone (AOR: 0.68; 95%CI: 0.57-0.82; p<0.001) or in the field (AOR: 0.41; 95%CI: 0.20-0.87; p<0.05) had a lower odds of re-infection compared to males who were not interviewed.  No significant associations were found between interview type and re-infection among females. 

Conclusions: DIS interviews of gonorrhea cases were associated with a lower odds of re-infection for males, particularly if the interview occurred outside of the reporting facility.  Future work should focus on identifying specific aspects of interviews that are associated with reduced re-infection.