Identification of TB space-time clusters and hotspots in Ouest département, Haiti, 2011-2016

BACKGROUND

Haiti has the highest incidence rate of TB in the Western Hemisphere, with an estimated 170 cases per 100,000 in 2019. Since 2010, control efforts have focused on targeted case-finding activities in urban areas, implementation of rapid molecular diagnostics at high-volume TB centers, and improved reporting. TB analyses are rarely focused on lower geographic units; thus, the major goal was to determine if there were focal areas of TB transmission from 2011 to 2016 at operational geographic levels useful for the National TB Control Program (PNLT).

METHODS

We created a geocoder to locate TB cases at the smallest geographic level. Kulldorff's space-time permutation scan, Anselin Moran's I, and Getis-Ord Gi* statistics were used to determine the spatial distribution and clusters of TB.

RESULTS

With 91% of cases linked using the geocoder, TB clusters were identified each year. Getis-Ord Gi* analysis revealed 14 distinct spatial clusters of high incidences in the Port-au-Prince metropolitan area. One hundred retrospective space-time clusters were detected.

CONCLUSION

Our study confirms the presence of TB hotspots in the Ouest département, with most clusters in the Port-au-Prince metropolitan area. Results will help the PNLT and its partners better design case-finding strategies for these areas.

Loss to follow-up among patients receiving anti-tuberculosis treatment, Haiti, 2011-2015

Setting: Tuberculosis (TB) treatment facilities in Haiti. Objective: To assess factors associated with loss to follow-up (LTFU) among patients receiving treatment for tuberculosis (TB) in Haiti. Design: We analyzed Haiti's national surveillance data for patients started on anti-tuberculosis treatment from 2011 to 2015 to determine factors associated with LTFU using multivariable logistic regression and describe LTFU in terms of subnational units to target future intervention strategies. We also conducted a survival analysis to estimate hazard ratios of factors associated with time to LTFU. Results: Of 81 490 TB cases reported, 7423 (9.1%) were LTFU during anti-tuberculosis treatment, increasing from 7.1% in 2011 to 10.3% in 2015. Six high-volume facilities had significantly higher rates of LTFU (14.3-31.9%) than the rest of the country, accounting for 18.8% of all TB cases reported, but 41.7% of all LTFU patients. Male sex, previous treatment history, and human immunodeficiency virus infection were associated with higher rates of LTFU. The median time to LTFU was 94 days. Conclusion: A small number of facilities accounted for disproportionately high rates of LTFU. These results identify characteristics of facilities and individuals leading to concentrated interventions to reduce LTFU and improve treatment success.