title: Impact of changing diagnostic criteria for smear-positive tuberculosis: a cohort study in Malawi.
abstract: We assessed the impact on measured burden and outcomes of the revised World Health Organization and Malawi guidelines reclassifying people with single (including 'scanty') positive smears as smear-positive pulmonary tuberculosis cases. In a retrospective cohort in rural Malawi, 567 (34%) of 1670 smear-positive episodes were based on single positive smears (including 176 with scanty smears). Mortality rates and the proportion starting treatment were similar in those with two positive smears or single, non-scanty smears. Those with single scanty smears had higher mortality and a lower proportion starting treatment. The reclassification will increase the reported burden substantially, but should improve treatment access.
authors.affiliation: <label>*</label>London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: O
authors.initials: O
authors.lastname: Koole
authors.affiliation: <label><sup>†</sup></label>Karonga Prevention Study, Chilumba.
authors.forename: L
authors.initials: L
authors.lastname: Munthali
authors.affiliation: <label><sup>‡</sup></label>Ministry of Health, Karonga.
authors.forename: B
authors.initials: B
authors.lastname: Mhango
authors.affiliation: <label><sup>§</sup></label>National TB Control Programme, Lilongwe, Malawi.
authors.forename: J
authors.initials: J
authors.lastname: Mpunga
authors.affiliation: <label>*</label>London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Glynn
authors.affiliation: <label>*</label>London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: A C
authors.initials: AC
authors.lastname: Crampin
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008295:Malawi / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000453:epidemiology / Q000401:mortality; D014944:World Health Organization
chemical_list: D000995:Antitubercular Agents