Modifiable risk factors for typhoid intestinal perforations during a large outbreak of typhoid fever, Kampala Uganda, 2015

AUTHOR

Bulage L, Masiira B, Ario AR, Matovu JKB, Nsubuga P, Kaharuza F, Nankabirwa V, Routh J, Zhu BP

ABSTRACT

BACKGROUND: Between January and June, 2015, a large typhoid fever outbreak occurred in Kampala, Uganda, with 10,230 suspected cases. During the outbreak, area surgeons reported a surge in cases of typhoid intestinal perforation (TIP), a complication of typhoid fever. We conducted an investigation to characterize TIP cases and identify modifiable risk factors for TIP.

METHODS: We defined a TIP case as a physician-diagnosed typhoid patient with non-traumatic terminal ileum perforation. We identified cases by reviewing medical records at all five major hospitals in Kampala from 2013 to 2015. In a matched case-control study, we compared potential risk factors among TIP cases and controls; controls were typhoid patients diagnosed by TUBEX TF, culture, or physician but without TIP, identified from the outbreak line-list and matched to cases by age, sex and residence. Cases and controls were interviewed using a standard questionnaire from 1st -23rd December 2015. We used conditional logistic regression to assess risk factors for TIP and control for confounding.

RESULTS: Of the 88 TIP cases identified during 2013-2015, 77% (68/88) occurred between January and June, 2015; TIPs sharply increased in January and peaked in March, coincident with the typhoid outbreak. The estimated risk of TIP was 6.6 per 1000 suspected typhoid infections (68/10,230). The case-fatality rate was 10% (7/68). Cases sought care later than controls; Compared with 29% (13/45) of TIP cases and 63% (86/137) of controls who sought treatment within 3 days of onset, 42% (19/45) of cases and 32% (44/137) of controls sought treatment 4-9 days after illness onset (ORadj = 2.2, 95%CI = 0.83-5.8), while 29% (13/45) of cases and 5.1% (7/137) of controls sought treatment ≥10 days after onset (ORadj = 11, 95%CI = 1.9-61). 68% (96/141) of cases and 23% (23/100) of controls had got treatment before being treated at the treatment centre (ORadj = 9.0, 95%CI = 1.1-78).

CONCLUSION: Delay in seeking treatment increased the risk of TIPs. For future outbreaks, we recommended aggressive community case-finding, and informational campaigns in affected communities and among local healthcare providers to increase awareness of the need for early and appropriate treatment.

Click here to view the article, published in BMC Infectious Diseases