Browsing by Author "Robsky, Katherine O."
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Item Characterization of geographic mobility among participants in facility- and community-based tuberculosis case finding in urban Uganda(PLoS ONE, 2021) Robsky, Katherine O.; Isooba, David; Nakasolya, Olga; Mukiibi, James; Nalutaaya, Annet; Kitonsa, Peter J.; Kamoga, Caleb; Baik, Yeonsoo; Kendall, Emily A.; Katamba, Achilles; Dowdy, David W.International and internal migration are recognized risk factors for tuberculosis (TB). Geographic mobility, including travel for work, education, or personal reasons, may also play a role in TB transmission, but this relationship is poorly defined. We aimed to define geographic mobility among participants in facility- and community-based TB case finding in Kampala, Uganda, and to assess associations between mobility, access to care, and TB disease. Methods We included consecutive individuals age �15 years diagnosed with TB disease through either routine health facility practices or community-based case finding (consisting of doorto- door testing, venue-based screening, and contact investigation). Each case was matched with one (for community-based enrollment) or two (health facility enrollment) TB-negative controls. We conducted a latent class analysis (LCA) of eight self-reported characteristics to identify and define mobility; we selected the best-fit model using Bayesian Information Criterion. We assessed associations between mobility and TB case status using multivariable conditional logistic regression. Results We enrolled 267 cases and 432 controls. Cases were more likely than controls to have been born in Kampala (p<0.001); there was no difference between cases and controls for remaining mobility characteristics. We selected a two-class LCA model; the “mobile” class was perfectly correlated with a single variable: travel (>3 km) from residence 2 times per month. Mobility was associated with a 28% reduction in odds of being a TB case (adjusted matched odds ratio 0.72 [95% confidence interval 0.49, 1.06]). Conclusion Frequency of out-of-neighborhood travel is an easily measured variable that correlates closely with predicted mobility class membership. Mobility was associated with decreased risk of TB disease; this may be in part due to the higher socioeconomic status of mobile individuals in this population. However, more research is needed to improve assessment of mobility and understand how mobility affects disease risk and transmission.Item Is distance associated with tuberculosis treatment outcomes? A retrospective cohort study in Kampala, Uganda(BMC infectious diseases, 2020) Robsky, Katherine O.; Hughes, Seamus; Kityamuwesi, Alex; Kendall, Emily A.; Kitonsa, Peter James; Dowdy, David W.; Katamba, AchillesChallenges accessing nearby health facilities may be a barrier to initiating and completing tuberculosis (TB) treatment. We aimed to evaluate whether distance from residence to health facility chosen for treatment is associated with TB treatment outcomes. Methods: We conducted a retrospective cohort study of all patients initiating TB treatment at six health facilities in Kampala from 2014 to 2016. We investigated associations between distance to treating facility and unfavorable TB treatment outcomes (death, loss to follow up, or treatment failure) using multivariable Poisson regression. Results: Unfavorable treatment outcomes occurred in 20% (339/1691) of TB patients. The adjusted relative risk (aRR) for unfavorable treatment outcomes (compared to treatment success) was 0.87 (95% confidence interval [CI] 0.70, 1.07) for patients living ≥2 km from the facility compared to those living closer. When we separately compared each type of unfavorable treatment outcome to favorable outcomes, those living ≥2 km from the facility had increased risk of death (aRR 1.42 [95%CI 0.99, 2.03]) but decreased risk for loss to follow-up (aRR 0.57 [95%CI 0.41, 0.78]) than those living within 2 km. Conclusions: Distance from home residence to TB treatment facility is associated with increased risk of death but decreased risk of loss to follow up. Those who seek care further from home may have advanced disease, but once enrolled may be more likely to remain in treatment.Item Low prevalence of diabetes mellitus among tuberculosis patients and their community in urban Uganda(The official journal of the International Union against Tuberculosis and Lung Disease, 2021) Kamoga, Caleb Erisa; Robsky, Katherine O.; Kitonsa, Peter James; Nalutaaya, Annet; Isooba, David; Nakasolya, Olga; Mukiibi1, James; Dowdy, David; Kendall, Emily A.; Katamba, AchillesGlobally, epidemics of diabetes mellitus (DM) and tuberculosis (TB) are increasingly linked.1,2 Diabetes is associated with TB infection and with a two-to-four-fold increase in the risk of active disease;3 active TB may also increase the risk of diabetes.4 In sub- Saharan Africa, where the prevalence of diabetes in the general population is lower than in other regions,5 the prevalence of diabetes among patients with TB has been estimated at 9%.6 However, many studies that contributed to that estimate, including one in Uganda,7 evaluated only hospitalized TB patients and may not be representative of the region’s TB epidemic as a whole. There are few data from sub-Saharan African settings on the prevalence of DM among non-hospitalized TB patients or people with TB who have not yet sought treatment. Therefore, the extent to which diabetes detection or management should be integrated with TB care in this region remains unclear.Item Spatial distribution of people diagnosed with tuberculosis through routine and active case finding: a community-based study in Kampala, Uganda(Infectious diseases of poverty, 2020) Robsky, Katherine O.; Kitonsa, Peter J.; Mukiibi, James; Nakasolya, Olga; Isooba, David; Nalutaaya, Annet; Salvatore, Phillip P.; Kendall, Emily A.; Katamba, Achilles; Dowdy, DavidRoutine tuberculosis (TB) notifications are geographically heterogeneous, but their utility in predicting the location of undiagnosed TB cases is unclear. We aimed to identify small-scale geographic areas with high TB notification rates based on routinely collected data and to evaluate whether these areas have a correspondingly high rate of undiagnosed prevalent TB. Methods: We used routinely collected data to identify geographic areas with high TB notification rates and evaluated the extent to which these areas correlated with the location of undiagnosed cases during a subsequent community-wide active case finding intervention in Kampala, Uganda. We first enrolled all adults who lived within 35 contiguous zones and were diagnosed through routine care at four local TB Diagnosis and Treatment Units. We calculated average monthly TB notification rates in each zone and defined geographic areas of “high risk” as zones that constituted the 20% of the population with highest notification rates. We compared the observed proportion of TB notifications among residents of these high-risk zones to the expected proportion, using simulated estimates based on population size and random variation alone. We then evaluated the extent to which these high-risk zones identified areas with high burdens of undiagnosed TB during a subsequent community-based active case finding campaign using a chi-square test. Results: We enrolled 45 adults diagnosed with TB through routine practices and who lived within the study area (estimated population of 49 527). Eighteen zones reported no TB cases in the 9-month period; among the remaining zones, monthly TB notification rates ranged from 3.9 to 39.4 per 100 000 population. The five zones with the highest notification rates constituted 62% (95% CI: 47–75%) of TB cases and 22% of the population–significantly higher than would be expected if population size and random chance were the only determinants of zone-to-zone variation (48%, 95% simulation interval: 40–59%). These five high-risk zones accounted for 42% (95% CI: 34–51%) of the 128 cases detected during the subsequent community-based case finding intervention, which was significantly higher than the 22% expected by chance (P < 0.001) but lower than the 62% of cases notified from those zones during the pre-intervention period (P = 0.02). Conclusions: There is substantial heterogeneity in routine TB notification rates at the zone level. Using facilitybased TB notification rates to prioritize high-yield areas for active case finding could double the yield of such casefinding interventions.Item The Spectrum of Tuberculosis Disease in an Urban Ugandan Community and Its Health Facilities(Clinical Infectious Diseases, 2021) Kendall, Emily A.; Kitonsa, Peter J.; Nalutaaya, Annet; Erisa, Caleb; Mukiibi, James; Nakasolya, Olga; Isooba, David; Baik, Yeonsoo; Robsky, Katherine O.; Kato-Maeda, Midori; Cattamanchi, Adithya; Katamba, Achilles; Dowdy, David W.New, sensitive diagnostic tests facilitate identification and investigation of milder forms of tuberculosis (TB) disease. We used community-based TB testing with the Xpert MTB/RIF Ultra assay (“Ultra”) to characterize individuals with previously undiagnosed TB and compare them to those from the same community who were diagnosed with TB through routine care. Methods. We offered community-based sputum Ultra testing to adult residents of a well-defined area (population 34 000 adults) in Kampala, Uganda, via door-to-door screening and venue-based testing, then used detailed interview and laboratory testing to characterize TB-positive individuals. We compared these individuals to residents diagnosed with pulmonary TB at local health facilities and a representative sample of residents without TB (controls). Results. Of 12 032 residents with interpretable Ultra results, 113 (940 [95% confidence interval {CI}, 780–1130] per 100 000) tested positive, including 71 (63%) positive at the lowest (trace) level. A spectrum of TB disease was observed in terms of chronic cough (93% among health facility–diagnosed cases, 77% among residents with positive community-based Ultra results at levels above trace, 33% among trace-positive community participants, and 18% among TB-negative controls), TB symptom prevalence (99%, 87%, 60%, and 38%, respectively), and C-reactive protein (75th percentile: 101 mg/L, 28 mg/L, 6 mg/L, and 4 mg/L, respectively). Community-diagnosed cases were less likely than health facility–diagnosed cases to have human immunodeficiency virus coinfection or previous TB. The specificity of Ultra was 99.4% (95% CI, 99.2%–99.5%) relative to a single spot sputum culture. Conclusions. People with undiagnosed prevalent TB in the community have different characteristics than those diagnosed with pulmonary TB in health facilities. Newer diagnostic tests may identify a group of people with early or very mild disease. Keywords. active case-finding; Xpert MTB/RIF Ultra; subclinical tuberculosis; prevalent tuberculosis.