Incidence of pulmonary tuberculosis in suburban Bissau, Guinea-Bissau between 2004 and 2020: a prospective cohort study.

OBJECTIVES: Previous studies have found declining incidence of tuberculosis (TB) in Bissau, Guinea-Bissau. This study aimed to report incidence rates of TB for the period 2004-2020, stratifying by sex, smear-status, and HIV-status, as well as describe developments in TB case fatality rate and diagnostic delay. DESIGN AND METHODS: Data from the Bandim Health Project HDSS and the TB registry from Jan 1st, 2004 to Dec 31st, 2020 were used. Incidence rates were calculated for each year and for smear-positive, smear-negative, HIV-positive, HIV-negative, and unknown HIV-status. Incidence rate ratio and test for trend were done using a one-step Newton approximation to the log-linear Poisson regression coefficient. RESULTS: Overall TB incidence declined only slightly over the period from 294 per 100,000 in 2004 to 273 in 2020. TB/HIV coinfection declined from 108 in 2004 to 14 in 2020, as did incidence among females and smear-negative cases. CONCLUSIONS: Incidence of PTB in Bissau, Guinea-Bissau is declining slowly, if at all. TB incidence among females, smear-negative TB, TB case fatality rate, and TB/HIV coinfection and diagnostic delay are declining.

Active case-finding of tuberculosis in general populations and at-risk groups: a systematic review and meta-analysis.

BACKGROUND: The World Health Organization (WHO) recommends active case-finding (ACF) of tuberculosis (TB) in certain high-risk groups; however, more evidence is needed to elucidate the scope of ACF beyond the current recommendations. In this study we aimed to systematically review yields (the prevalence of active TB) of studies on ACF in general populations and at-risk groups. METHODS: A literature search in PubMed, Embase and the Cochrane Central Library (CENTRAL) was performed for studies concluded after 31 December 1999 and published before 1 September 2020. Screening yields were estimated and yield/prevalence ratios (ratio between yield of study and WHO estimated prevalence of TB) were calculated to assess which groups might especially benefit from ACF. Finally, risk of bias was assessed and heterogeneity was investigated using meta-regression and sensitivity analyses. RESULTS: We included 197 studies, with a total of 12 372 530 screened and 53 158 cases found. Yields were high among drug users, close contacts, the poor and marginalised, people living with HIV, and prison inmates across incidence strata, and estimated yield/prevalence ratios in screenings of general populations tended to be >1 with an overall ratio of 1.4 and ranging between 1.0 and 1.5. Sensitivity analyses suggested that inclusion of studies at high risk of bias contributed to underestimation of yields. CONCLUSION: Despite many studies using insensitive screening methods, these results suggest that more at-risk groups should be considered for inclusion in future screening recommendations and that screening of general populations may outperform current case-finding practices, providing evidence for extending ACF beyond the current recommendations.

BCG is protective against death in male but not female patients with pulmonary tuberculosis in Guinea-Bissau.

BACKGROUND: Growing evidence supports the existence of a sex difference in immunity to tuberculosis (TB). This is most often to the detriment of males. This study aimed to assess the association between scar size from bacillus Calmette-Guérin (BCG) and mortality risk stratified by sex. METHODS: Kaplan-Meier survivor functions and Cox proportional hazard models were used to assess mortality risk by sex and scar size. Groups were further compared by clinical and epidemiological characteristics. RESULTS: Between 2003 and 2019, 2944 eligible patients were identified, of whom 1003 were included in the final analysis. Males with BCG scars, particularly large scars, were less likely to die within 1 y of diagnosis than males with no scar (adjusted hazard ratio 0.36 [95% confidence interval 0.15 to 0.88]). In contrast, females with small scars trended towards higher mortality than females with no scars or females with large scars. CONCLUSIONS: BCG protects against death in male but not female patients with TB. More research is needed to determine the mechanisms underpinning these sex differences and whether they are generalizable beyond this setting.

Life expectancy among patients with pulmonary tuberculosis is less than one-third of life expectancy in the background population in Guinea-Bissau-an observational study.

BACKGROUND: Few studies have assessed life expectancy of patients with tuberculosis (TB) against a comparable background population, particularly in low-income, high-incidence settings. This study aimed to estimate the life expectancy (LE) of patients with TB in the West African country of Guinea-Bissau and compare it with the LE of the background population. METHODS: This study used data from the Bandim TB cohort from 2004-20 as well as census data from the capital of Guinea-Bissau. LE was estimated using a bootstrapped Kaplan-Meier survival analysis for patients with TB and the background population, stratifying by age of entry and various patient subgroups. The analysis was further stratified by diagnosis period and length of schooling (an indicator of socioeconomic status), to assess their influence on LE. A sensitivity analysis was performed assuming death at loss to follow-up. RESULTS: The analysis included 2278 patients and a background population of 169 760 individuals. Overall median LE among 30-year-old patients with TB was 10.7 years (95% CI: 8.7-12.6), compared with 35.8 (95% CI: 35.1-36.5) in the background population. LE was shorter in HIV-infected patients and those who had unsuccessful treatment outcome; however, even among those who were both uninfected with HIV and experienced successful treatment outcome, LE was 20% shorter than in the background population. Longer schooling appeared to decrease mortality. CONCLUSIONS: TB substantially shortens LE. This effect is present even in patients who are uninfected with HIV and who have successful treatment outcome.

Assessing gender differences among presumed and diagnosed patients with pulmonary TB: observations from Guinea-Bissau.

BACKGROUND: Globally, more males than females are diagnosed with pulmonary TB (PTB); however, the cause of this gender disparity remains unknown. We aimed to assess gender differences in an observational cohort of patients with presumed PTB (prePTB) at the Bandim Health Project, Guinea-Bissau. METHODS: Adult patients with signs and symptoms suggestive of PTB seeking medical care were invited to participate and were referred to comprehensive diagnostic work-up. RESULTS: We included 2020 patients with prePTB; 54.6% were female. Females were younger than males and more often infected with HIV. More male patients with prePTB were diagnosed with PTB and the proportion of smear-positive cases was greater among males. There was no gender difference in loss to follow-up during the diagnostic process. Of 219 patients with PTB, 205 started treatment, with no difference between genders regarding pretreatment loss to follow-up or treatment outcome. CONCLUSIONS: More women sought help for symptoms indicative of PTB, yet more men were diagnosed. Women did not have more clinically severe disease at presentation, did not drop out of diagnostic procedures more frequently and did not experience a worse outcome than men. This suggests that the gender gap in PTB is unlikely to be due solely to differences in care-seeking behaviour or diagnostic procedures in our setting.

Genetic disruption of slc4a10 alters the capacity for cellular metabolism and vectorial ion transport in the choroid plexus epithelium.

BACKGROUND: Genetic disruption of slc4a10, which encodes the sodium-dependent chloride/bicarbonate exchanger Ncbe, leads to a major decrease in Na+-dependent HCO3- import into choroid plexus epithelial cells in mice and to a marked reduction in brain intraventricular fluid volume. This suggests that Ncbe functionally is a key element in vectorial Na+ transport and thereby for cerebrospinal fluid secretion in the choroid plexus. However, slc4a10 disruption results in severe changes in expression of Na+,K+-ATPase complexes and other major transport proteins, indicating that profound cellular changes accompany the genetic manipulation. METHODS: A tandem mass tag labeling strategy was chosen for quantitative mass spectrometry. Alterations in the broader patterns of protein expression in the choroid plexus in response to genetic disruption of Ncbe was validated by semi-quantitative immunoblotting, immunohistochemistry and morphometry. RESULTS: The abundance of 601 proteins were found significantly altered in the choroid plexus from Ncbe ko mice relative to Ncbe wt. In addition to a variety of transport proteins, particularly large changes in the abundance of proteins involved in cellular energy metabolism were detected in the Ncbe ko mice. In general, the abundance of rate limiting glycolytic enzymes and several mitochondrial enzymes were reduced following slc4a10 disruption. Surprisingly, this was accompanied by increased ATP levels in choroid plexus cells, indicating that the reduction in capacity for energy metabolism was adaptive to high ATP rather than causal for a decreased capacity for ion and water transport. Ncbe-deficient cells also had a reduced cell area and decreased K+ content. CONCLUSION: Our findings suggest that the lack of effective Na+-entry into the epithelial cells of the choroid plexus leads to a profound change in the cellular phenotype, shifting from a high-rate secretory function towards a more dormant state; similar to what is observed during ageing or Alzheimer's disease.