Monitoring tuberculosis treatment outcome: analysis of national surveillance data from a clinical perspective
- 1Institute of Public Health, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- 2Regional Epidemiology Unit, Health Protection Agency, East of England, University Forvie Site, Cambridge, Cambridge, UK
- 3Respiratory Diseases Department, Centre for Infections, Health Protection Agency, Colindale, London, UK
- 4Birmingham Heartlands Hospital, Birmingham, UK
- 5School of Medicine, Health Policy and Practice, University of East Anglia, Norwich, UK
- 6Hospital Medicine, Hopital General Douala, Cameroon, Faculty of Medicine and Biomedical Sciences, Yaounde-Cameroon
- Dr I Abubakar, Tuberculosis Section, Respiratory Diseases Department, Centre for Infections, Health Protection Agency, London NW9 5EQ, UK;
- Received 23 October 2006
- Accepted 22 June 2007
- Published Online First 5 July 2007
Background: In 1998, the World Health Organization (WHO) and the International Union Against Tuberculosis and Lung Disease (IUATLD) published recommendations standardising the evaluation of tuberculosis treatment outcome in Europe. These guidelines fail to account for clinically appropriate alterations in the management of patients.
Objectives: To evaluate tuberculosis treatment outcome in England, Wales and Northern Ireland by redefining the outcome criteria and investigate factors associated with unsuccessful treatment outcome 12 months after notification.
Methods: This was a prospective analysis of a cohort of patients diagnosed in England, Wales and Northern Ireland and reported to the Enhanced Tuberculosis Surveillance system in 2001 and 2002. Proportions of success and failure were calculated based on a new set of criteria following discussion with clinicians treating tuberculosis cases. Logistic regression was used to study risk factors for unsuccessful treatment outcome.
Results: 13 048 cases were notified in the study period. Of the 2676 that were identified as new sputum smear positive pulmonary cases, 2209 (82.5%) had treatment outcome data reported. Using the WHO/IUATLD criteria, 76.8% were classified as successful. In contrast, applying the new criteria, the success rate was 87.5%. This rate exceeds the 85% success target set by the WHO. Risk factors for unsuccessful treatment outcome included male sex (OR 1.27; 95% CI 1.08 to 1.49), being elderly (p trend <0.001), having pulmonary tuberculosis (OR 1.28; 95% CI 1.08 to 1.53) and having resistance to any antituberculosis drug (OR 1.90; 95% CI 1.44 to 2.52).
Conclusion: The proportion of tuberculosis cases with a successful treatment outcome exceeded the target of 85% success rate based on the modified outcome categories. Although the tuberculosis treatment outcome criteria set by WHO/IUATLD appear to be clear, they mix measures of process and outcome. Further refinement may be necessary in low incidence high income countries, especially those with a high mortality among the elderly.
Competing interests: None.
Ethical approval: This study was carried out with national surveillance data. The Health Protection Agency has PIAG approval to hold and analyse national surveillance data for public health purposes.