Clustered tuberculosis incidence in Bandar Lampung, Indonesia

Background: The incidence of tuberculosis (TB) in the city of Bandar Lampung,Indonesia, increased during the period 2009–2011, although the cure rate for TBcases treated under the directly observed treatment, short course (DOTS) strategyin the city has been maintained at more than 85%. Cluster analysis is recognizedas an interactive tool that can be used to identify the significance of spatiallygrouping sites of TB incidence. This study aimed to identify space–time clusters ofTB during January to July 2012 in Bandar Lampung, and assess whether clusteringco-occurred with locations of high population density and poverty.Methods: Medical records were obtained of smear-positive TB patients who werereceiving treatment at DOTS facilities, located at 27 primary health centres andone hospital, during the period January to July 2012. Data on home addressesfrom all cases were geocoded into latitude and longitude coordinates, using globalpositioning system (GPS) tools. The coordinate data were then analysed usingSaTScan.Results: Two significant clusters were identified with P value of 0.05 for theprimary cluster and 0.1 for the secondary cluster. Clusters occurred in areas withhigh population density and a high proportion of poor families and poor housingconditions. The short radius of the clusters also indicated the possibility of localtransmission of TB.Conclusions: The incidence of TB in Bandar Lampung was not randomlydistributed, but significantly concentrated in two clusters. Identification of clustersof TB, together with its etiological factors such as social determinants, and riskfactors, can be used to support TB control programmes, particularly those aimingto reach vulnerable populations, and intensified case-finding.