Objective Tsutsugamushi disease (scrub typhus) is caused by Orientia tsutsugamushi, and has been endemic in Asia and Western Pacific islands. Though sporadic case reports have described the clinical consequences of this vector-borne disease, data on the actual incidence of complications or mortality are scarce. It also remains unclear how a delay in effective treatments affects the occurrence of complications associated with this Rickettsial disease.
Methods Using the Japanese Diagnosis Procedure Combination inpatient database in Japan, we identified patients with Tsutsugamushi disease between July 1 and December 31 in 2007 and 2008. We examined location of hospitals, patient's age, sex, comorbidities, complications, inhospital deaths, date of admission, date of starting therapy with tetracyclines. A logistic regression was conducted to analyze the association between delay in effective treatments and the occurrence of complications.
Results A total of 210 cases were identified. Overall, 29 (13.8%) had at least one complication and two deaths were identified. Age was a significant risk factor for complications [odds ratio (OR), 1.48; 95% confidence interval (CI), 1.08-2.03; p=0.014, for a 10-year age increase]. Patients with ≥2 days delay in treatment with tetracyclines had a significantly higher risk of complications compared to those with no delay (OR, 2.71; 95% CI, 1.03-7.12; p=0.044).
Conclusion Tsutsugamushi disease remains a threat to public health. Our study clearly indicates the importance of early diagnosis and immediate tetracycline treatment to prevent severe complications in Tsutsugamushi disease.