Shewhart Charts and Two-Monthly Screening Interval to Monitor Hepatitis C and Hepatitis B Virus Infections in Two-Year Prospective Cohort Study of Hemodialysis Patients in Vietnam Pages 5-14

Cuong Minh Duong, Robin Turner and Mary-Louise McLaws

School of Public Health and Community Medicine, UNSW Medicine, UNSW Australia

DOI: http://dx.doi.org/10.12970/2310-984X.2016.04.01.3

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Abstract: Background: Early detection of an increase in the rate of hepatitis C (HCV) and hepatitis B (HBV) acquired during healthcare in hemodialysis setting allows rapid assessment and intervention to prevent subsequent sero-conversions. We retrospectively examined the application of the Shewhart chart to our two-year cohort study to early detect temporal change in HCV and HBV sero-conversions among hemodialysis patients in low-resourced setting provided that there was a known investigated outbreak of HCV occurring in this study period. We also reported our findings of the incidence density, prevalence, genotype and subtype of HCV and HBV infections and their associated risk factors.

Methods: All 201 patients treated at the District-6 Hospital in Ho Chi Minh City, Vietnam participated in a prospective cohort study between 2012 and 2014. Patients consented to be tested for HBV surface antigen (HBsAg) and HCV core antigen (HCV-coreAg) and provided information on demographics, lifestyle risk factors and treatment related risk factors two-monthly through an administered questionnaire. Positive patients were tested for viral genotypes. Sero-conversions were plotted retrospectively on a P-control chart.

Results: HCV and HBV prevalence rates were 12% (95%CI 8% – 18%) and 8% (95%CI 5% – 12%) respectively. HCV and HBV incidence density rates were 5 (95%CI 3-9) and 2 (95% CI 1-4) new cases per 1,000 person-months. These incidence and prevalence rates of HCV and HBV were not statistically different (P>0.05) except in follow-up months 13 and 14 when HCV outbreak occurred (P = 0.0008). An alarming increase in both HBV (months 11 and 12) and HCV (months 13 and 14) infection was demonstrated by Shewhart chart. Infection control lapses were identified as the cause of these increases. Among typable patients, 5 had HCV genotype 1b, 3 (genotype 1a) and 2 (genotype 6a). Two patients tested HBV genotype B.

Conclusion: The applicable Shewhart control chart and two-monthly screening interval should be routinely utilized to detect potential HCV and HBV outbreak in low-resourced hemodialysis settings so that improvement interventions can be in place timely to prevent the spread of diseases. Strict adherence to infection control measures and routine infection control improvement strategies are vital in preventing these healthcare associated infections.

Keywords: HCV, HBV, hemodialysis, Vietnam, quality control chart, prevalence, incidence density.
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