Immunisation Hepatitis and Blood Safety Department, Public Health England, Colindale, London, UK.
Background & Aims: To develop and validate an algorithm to monitor rates of, and response to, treatment of patients infected with hepatitis C virus (HCV) across England using routine laboratory HCV RNA testing data. Methods: Hepatitis C testing activity between January 2002 and December011 was extracted from the local laboratory information systems of a sentinel network of 23 laboratories across England. An algorithm based on frequency of HCV RNA testing within a defined time period was designed to identify treated patients. Validation of the algorithm was undertaken for one centre by comparison with treatment data recorded in a clinical database managed by the Trent HCV study group. Results: In total, 267,887 HCV-RNA test results from 100,640 individuals were extracted. Of these, 78.9% (79,360) tested positive for viral RNA, indicating an active infection, 20.8% (16,538) of whom had a repeat pattern of HCV-RNA testing suggestive of treatment-monitoring. Annual numbers of individuals treated increased rapidly from 468 in 2002, to 3,295 in 2009, but decreased to 3,110 in 2010. Approximately two thirds (63.3; 10,468) of those treated had results consistent with a sustained virological response, including 55.3% and 67.1% of those with a genotype-one and non-one virus, respectively. Validation against the Trent clinical database demonstrated that the algorithm was 95% sensitive and 93% specific in detecting treatment, and 100% sensitive and 93% specific for detecting treatment outcome. Conclusions: Laboratory testing activity, collected through a sentinel surveillance programme has enabled the first country-wide analysis of treatment and response among HCV-infected individuals. Our approach provides a sensitive, robust, and sustainable method for monitoring service provision across England.