The first national tuberculosis prevalence survey of Lao PDR (2010–2011)

• Published in: Tropical medicine & international health 2015-09, Vol.20 (9), p.1146-1154
• Main Authors: Law, Irwin, Sylavanh, Phannasinh, Bounmala, Soth, Nzabintwali, Fulgence, Paboriboune, Phimpha, Iem, Vibol, Somphavong, Silaphet, Kim, Sang Jae, Sismanidis, Charalambos, Onozaki, Ikushi, Sebert, Jacques
• Format: Article
• Language: English
• Subjects: Asia; Asie; Bacteriology; epidemiology; Epidemiología; estudio de prevalencia; Laos; Medical diagnosis; Medical screening; prevalence survey; surveillance de la prévalence; tuberculose; Tuberculosis; X-rays; épidémiologie
• ISSN: 1360-2276; 1365-3156
• DOI: 10.1111/tmi.12536

Summary Objective The objective of the study was to measure the prevalence of bacteriologically confirmed pulmonary tuberculosis (TB) in Lao PDR in 2010–2011. Method A nationwide, multistage cluster‐sampled cross‐sectional survey was undertaken in 2010–2011. All consenting participants ≥15 years were screened for pulmonary TB with chest X‐ray and symptom questionnaire. Two sputum specimens for bacteriological examination by microscopy and culture were collected from those who screened positive. Prevalence was estimated using multiple imputation and inverse probability weighting methods. Results Of 39 212 eligible participants from 50 clusters, 6290 participants provided at least one sputum sample for smear and culture. There were 237 bacteriologically confirmed pulmonary TB cases, 107 of which were smear‐positive. Chest X‐ray screening alone identified 230 (97.0%) cases compared with 118 (49.8%) by symptom screening alone. The estimated prevalence of smear‐positive and bacteriologically confirmed TB in those ≥15 years was 278 per 100 000 (95%C.I. 199–356) and 595 per 100 000 (95%C.I. 457–733), respectively. Prevalence significantly increased with age and was higher in men than women. Conclusions The prevalence of TB in Lao PDR is almost twice as high than previous estimates, with the greatest burden in the older population. Case detection efforts remain the primary goal of the national TB programme with case notifications being very low in comparison with the estimated number of prevalent cases. The survey observed major limitations with the diagnostic strategy of passive (symptom based) case finding that uses only direct smear microscopy for confirmation. Objectif Mesurer la prévalence de la TB pulmonaire confirmée bactériologiquement au Laos en 2010‐2011. Méthode Une enquête nationale, transversale, en plusieurs étapes, avec un échantillonnage en grappes a été menée en 2010‐2011. Tous les participants consentants ≥ 15 ans d’âge ont été testés pour la TB pulmonaire par la radiographie des poumons et un questionnaire sur les symptômes. Deux échantillons de crachats pour l'examen bactériologique par la microscopie et la culture ont été recueillis chez ceux trouvés positifs. La prévalence a été estimée en utilisant l'imputation multiple et les méthodes de pondération de la probabilité inverse. Résultats Sur 39 212 participants admissibles dans 50 grappes, 6290 ont fourni au moins un échantillon de crachat pour le frottis et la culture. Il y avait 237 cas de