Accuracy of different Xpert MTB/Rif implementation strategies in programmatic settings at the regional referral hospitals in Uganda: Evidence for country wide roll out

<div><p>Background</p><p>Xpert MTB/RIF assay is a highly sensitive test for TB diagnosis, but still costly to most low-income countries. Several implementation strategies instead of frontline have been suggested; however with scarce data. We assessed accuracy of different Xpert MTB/RIF implementation strategies to inform national roll-out.</p><p>Methods</p><p>This was a cross-sectional study of 1,924 adult presumptive TB patients in five regional referral hospitals of Uganda. Two sputum samples were collected, one for fluorescent microscopy (FM) and Xpert MTB/RIF examined at the study site laboratories. The second sample was sent to the Uganda Supra National TB reference laboratory for culture using both Lowenstein Jensen (LJ) and liquid culture (MGIT). We compared the sensitivities of FM, Xpert MTB/RIF and the incremental sensitivity of Xpert MTB/RIF among patients negative on FM using LJ and/or MGIT as a reference standard.</p><p>Results</p><p>A total 1924 patients were enrolled of which 1596 (83%) patients had at least one laboratory result and 1083 respondents had a complete set of all the laboratory results. A total of 328 (30%) were TB positive on LJ and /or MGIT culture. The sensitivity of FM was n (%; 95% confidence interval) 246 (63.5%; 57.9–68.7) overall compared to 52 (55.4%; 44.1–66.3) among HIV positive individuals, while the sensitivity of Xpert MTB/RIF was 300 (76.2%; 71.7–80.7) and 69 (71.6%; 60.5–81.1) overall and among HIV positive individuals respectively. Overall incremental sensitivity of Xpert MTB/RIF was 60 (36.5%; 27.7–46.0) and 20 (41.7%; 25.5–59.2) among HIV positive individuals.</p><p>Conclusion</p><p>Xpert MTB/RIF has a higher sensitivity than FM both in general population and HIV positive population. Xpert MTB/RIF offers a significant increase in terms of diagnostic sensitivity even when it is deployed selectively i.e. among smear negative presumptive TB patients. Our results support frontline use of Xpert MTB/RIF assay in high HIV/TB prevalent countries. In settings with limited access, mechanisms to refer smear negative sputum samples to Xpert MTB/RIF hubs are recommended.</p></div

Flow chart of patients with laboratory complete results.

<p>Flow chart of patients with laboratory complete results.</p

Diagnostic accuracy of smear and Xpert MTB/RIF among the MGIT and/or LJ culture positive (n = 328) tuberculosis participants.

<p>Diagnostic accuracy of smear and Xpert MTB/RIF among the MGIT and/or LJ culture positive (n = 328) tuberculosis participants.</p

Age- and sex-adjusted prevalence of pre-hypertension and hypertension by geographic region and age category.

<p>Age- and sex-adjusted prevalence of pre-hypertension and hypertension by geographic region and age category.</p

Association of region with prevalent hypertension among adults (≥18 years of age) before and after sequential adjustments for demographics and socio-economic status.

<p>Association of region with prevalent hypertension among adults (≥18 years of age) before and after sequential adjustments for demographics and socio-economic status.</p

Geographic differences in the prevalence of hypertension in Uganda: Results of a national epidemiological study

<div><p>Background</p><p>Hypertension accounts for more than 212 million global disability-adjusted life-years, and more than 15 million in sub-Saharan Africa. Identifying factors underlying the escalating burden of hypertension in sub-Saharan Africa may inform delivery of targeted public health interventions.</p><p>Methods</p><p>As part of the cross-sectional nationally representative Uganda National Asthma Survey conducted in 2016, we measured blood pressure (BP) in the general population across five regions of Uganda. We defined hypertension as systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg, or on-going use of medications for the purpose of lowering BP among adults (≥18 years of age); pre-hypertension as systolic BP between 120 and 140 mmHg and/or diastolic BP bteween 80 and 90 mmHg among adolescents and adults (≥12 years of age).</p><p>Findings</p><p>Of 3416 participants who met inclusion criteria, 38.9% were male, and mean age ± SD was 33.8 ± 16.9 years. The age- and sex-adjusted prevalence of hypertension was 31.5% (95% confidence interval [CI] 30.2 to 32.8). The adjusted prevalence of hypertension was highest in the Central Region (34.3%; 95% CI 32.6 to 36.0), and it was comparable to that in the West and East Regions. However, compared with the Central Region, hypertension was significantly less prevalent in the North (22.0%; 95 CI 19.4 to 24.6) and West Nile Regions (24.1%; 95% CI 22.0 to 26.3). Adjustment for demographic characteristics (occupation, monthly income, and educational attainment) of participants did not account for the significantly lower prevalence of hypertension in the North and West Nile Regions. The prevalence of pre-hypertension was 38.8% (95% CI 37.7 to 39.8), and it was highly prevalent among young adults (21–40 years of age: 42.8%; 95% CI 41.2–44.5%) in all regions.</p><p>Conclusions</p><p>Hypertension is starkly prevalent in Uganda, and numerous more people, including young adults are at increased risk. The burden of hypertension is highest in the Central, Western, and Eastern regions of the country; demographic characteristics did not fully account for the disparate regional burden of hypertension. Future studies should explore the potential additional impact of epidemiological shifts, including diet and lifestyle changes, on the development of hypertension.</p></div

Age- and sex-adjusted prevalence of hypertension among adults (≥18 years of age) in Uganda by geographical region.

<p>Age- and sex-adjusted prevalence of hypertension among adults (≥18 years of age) in Uganda by geographical region.</p

Predicted probabilities of being normotensive (left, upper: BP <120/80 mmHg), pre-hypertensive (right, upper: BP ≥120/80 but <140/90 mmHg), or hypertensive (left, lower: BP ≥140/90 mmHg) in five regions of Uganda according to age, years.

<p>Predicted probabilities of being normotensive (left, upper: BP <120/80 mmHg), pre-hypertensive (right, upper: BP ≥120/80 but <140/90 mmHg), or hypertensive (left, lower: BP ≥140/90 mmHg) in five regions of Uganda according to age, years.</p