Geographic mobility and treatment outcomes among people in care for tuberculosis in the Lake Victoria region of East Africa: A multi-site prospective cohort study

Abstract

Geographic mobility may disrupt continuity of care and contribute to poor clinical outcomes among people receiving treatment for tuberculosis (TB). This may occur especially where health services are not well coordinated across international borders, particularly in lower and middle income country settings. In this work, we describe mobility and the relationship between mobility and unfavorable TB treatment outcomes (i.e., death, loss to follow-up, or treatment failure) among a cohort of adults who initiated TB treatment at one of 12 health facilities near Lake Victoria. We abstracted data from health facility records for all 776 adults initiating TB treatment during a 6-month period at the selected facilities in Kenya, Tanzania, and Uganda. We interviewed 301 cohort members to assess overnight travel outside one's residential district/sub-county. In our analyses, we estimated the proportion of cohort members traveling in 2 and 6 months following initiation of TB treatment, explored correlates of mobility, and examined the association between mobility and an unfavorable TB treatment outcome. We estimated that 40.7% (95% CI: 33.3%, 49.6%) of people on treatment for TB traveled overnight at least once in the 6 months following treatment initiation. Mobility was more common among people who worked in the fishing industry and among those with extra-pulmonary TB. Mobility was not strongly associated with other characteristics examined, however, suggesting that efforts to improve TB care for mobile populations should be broad ranging. We found that in this cohort, people who were mobile were not at increased risk of an unfavorable TB treatment outcome. Findings from this study can help inform development and implementation of mobility-competent health services for people with TB in East Africa.

Fig 1. Health facilities included in this study.

These facilities were selected for enumeration of a cohort of people on TB treatment in the 2019 East Africa TB/HIV and Mobility Study. Map data are from OpenStreetMap (openstreetmap.org/copyright); map tiles by Stamen Design (http://maps.stamen.com/#watercolor/8/-1.300/32.900).

Fig 2. Estimates of mobility measures among cohort members in the months following TB treatment initiation.

Results are estimates for overnight travel outside one’s area of residence. Figures show the percentages of cohort members estimated to have a) traveled in or before the month (value labels show the cumulative percentages traveling by each month), b) traveled for more than 7 total nights in the month, and c) initiated a trip of 14 or more consecutive nights in or before the month (value labels show cumulative percentages). 95% confidence intervals are shown parenthetically. Data are from the 2019 East Africa TB/HIV and Mobility Study.

Fig 3. Risk of unfavorable TB treatment outcome following treatment initiation, by mobility pattern.

“No travel” indicates no overnight travel outside one’s area of residence in the 6-month period. “Limited travel” indicates no travel in the first 2 months (with travel as observed after the 2-month period). “Mobility as observed” presents the risk under the pattern of mobility observed in the cohort. Data are from the 2019 East Africa TB/HIV and Mobility Study.