Evidence map›Paper›PMID 42180402›Full record

ArticleEClinicalMedicine2026

Sputum scarcity and associated factors in people undergoing tuberculosis testing in South Africa, Uganda, India, and the Philippines: an analysis of cross-sectional observational data.

Welile V Nwamba, Anna O Okunola, Rebecca Crowder, Devasahayam J Christopher, William Worodria, Charles Yu, Zaida Palmer, Gcobisa Ndlangalavu, Daphne Naidoo, Ellen M H Mitchell and 3 more

Abstract read
In one paragraph

Article in EClinicalMedicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Welile V NwambaDSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa.
Anna O OkunolaDSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa.
Rebecca CrowderCenter for Tuberculosis and Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, USA.
Devasahayam J ChristopherDepartment of Pulmonary Medicine, Christian Medical College, Vellore, India.
William WorodriaWorld Alliance for Lung and Intensive Care, Kampala, Uganda.
Charles YuDepartment of Internal Medicine, College of Medicine, De La Salle Medical and Health Sciences Institute, Dasmariñas City, Cavite, The Philippines.
Zaida PalmerDSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa.
Gcobisa NdlangalavuDSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa.
Daphne NaidooDSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa.
Ellen M H MitchellDepartment of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.
Florian M MarxDepartment of Infectious Disease and Tropical Medicine, Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany.
Adithya CattamanchiCenter for Tuberculosis and Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, USA.
Grant TheronDSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, SAMRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Background: Tuberculosis (TB) testing often excludes people who cannot expectorate sputum. Non-sputum tests are a priority; however, there are limited data on the frequency and characteristics of sputum scarcity, which will influence the impact of non-sputum tests. Methods: We analysed adults with presumptive pulmonary TB recruited between February 2018 and February 2024 from a multi-country study (South Africa, Uganda, India, The Philippines; Cohort A, n = 2224), a South African cohort (Cohort B, n = 2179), and a South African cohort of people living with HIV (PLHIV) initiating antiretroviral therapy (ART) without syndromic selection (Cohort C, n = 297). Participants provided sputum for Xpert MTB/RIF Ultra (Ultra) and MGIT960 culture. Individuals unable to spontaneously produce sputum (non-salivary, ≥1 ml) underwent induction. We performed multivariable regression analysis and present adjusted ORs from LASSO to describe the relationship of variables with sputum scarcity. Separate sub-analysis was conducted for variables with >10% missing data. Findings: Overall, 13% (618/4700) people had sputum scarcity. Female sex [adjusted odds ratio [(aOR) 1.58 (95% confidence interval (CI) 1.31, 1.91)], and culture-negativity [1.45 (1.02, 2.08)] were positively associated with sputum scarcity. In Cohort A and B, country was also positively associated with sputum scarcity: India [1.43 (1.07, 1.91) and The Philippines [7.16 (5.34, 9.61] relative to South Africa. Smoking [0.61 (0.43, 0.88)], TB symptoms: cough [0.17 (0.13, 025)] and night sweats [0.71 (0.58, 0.86)] were negatively associated with sputum scarcity as well as previous TB [0.63 (0.47, 0.85)]. In people with TB, the only additional factor associated with sputum scarcity was, among PLHIV, being on ART [3.70 (1.19, 11.46)] were positively associated with sputum scarcity. Ultra sensitivity did not differ between induced and expectorated sputum [84% (64, 95) vs. 89% (84, 93); p = 0.218]. Interpretation: People with sputum scarcity are more likely to be female, do not smoke, have few symptoms and test culture-negative. Sputum scarcity also shows geographic variation. Among people with TB, those on ART are more likely to be sputum-scare. Sputum induction did not compromise Ultra sensitivity compared to expectorated sputum. These findings highlight people who may benefit most from non-sputum tests and the importance of such tests in people with milder disease. Funding: R2D2 TB Network and EDCTP programmes supported by the EU.

Indexed as

DiagnosisExpectorateSputum inductionSputum-scarceTuberculosis

Identifiers

PMID42180402
PMCPMC13195755

What Socratic holds

Textmetadata
LicenceCC BY-NC-ND
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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.