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Predictors for MTB Culture-Positivity among HIV-Infected Smear-Negative Presumptive Tuberculosis Patients in Uganda: Application of New Tuberculosis Diagnostic Technology.

Nakiyingi L, Nonyane BA, Ssengooba W, Kirenga BJ, Nakanjako D, Lubega G, Byakika-Kibwika P, Joloba ML, Ellner JJ, Dorman SE, Mayanja-Kizza H, Manabe YC - PLoS ONE (2015)

Bottom Line: New TB diagnostics such as urine TB lipoarabinomannan (LAM) could improve the accuracy and reduce delays in TB diagnosis in HIV-infected smear-negative presumptive TB.Abnormal CXR (aOR 3.68, 95% CI 1.76- 7.71, p=0.001) and positive urine TB-LAM (aOR 6.21, 95% CI 3.14-12.27, p< 0.001) were significantly associated with MTB culture-positivity.Validation studies to assess the performance of diagnostic algorithms that include urine TB-LAM in the diagnosis of smear-negative TB in HIV-infected individuals are warranted.

View Article: PubMed Central - PubMed

Affiliation: Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda; Department of Medicine, School of Medicine, Makerere University College of Heath Sciences, Kampala, Uganda.

ABSTRACT

Background: The existing World Health Organization diagnostic algorithms for smear-negative TB perform poorly in HIV-infected individuals. New TB diagnostics such as urine TB lipoarabinomannan (LAM) could improve the accuracy and reduce delays in TB diagnosis in HIV-infected smear-negative presumptive TB. We sought to determine predictors for MTB culture-positivity among these patients.

Methods: This study was nested into a prospective evaluation of HIV-infected outpatients and inpatients clinically suspected to have TB who were screened by smear-microscopy on two spot sputum samples. Data on socio-demographics, clinical symptoms, antiretroviral therapy, CXR, CD4 count, mycobacterial sputum and blood cultures and TB-LAM were collected. Logistic regression and conditional inference tree analysis were used to determine the most predictive indicators for MTB culture-positivity.

Results: Of the 418 smear-negative participants [female, 64%; median age (IQR) 32 (28-39) years, median CD4 106 (IQR 22 - 298) cells/mm3], 96/418 (23%) were sputum and/ or blood culture-positive for Mycobacterium tuberculosis (MTB) complex. Abnormal CXR (aOR 3.68, 95% CI 1.76- 7.71, p=0.001) and positive urine TB-LAM (aOR 6.21, 95% CI 3.14-12.27, p< 0.001) were significantly associated with MTB culture-positivity. Previous TB treatment (aOR 0.41, 95% CI 0.17-0.99, p=0.049) reduced the likelihood of a positive MTB culture. A conditional inference tree analysis showed that positive urine TB-LAM and abnormal CXR were the most predictive indicators of MTB culture-positivity. A combination of urine TB-LAM test and CXR had sensitivity and specificity of 50% and 86.1% respectively overall, and 70.8% and 84.1% respectively among those with CD4<100 cells/mm3.

Conclusions: A positive urine TB-LAM test and an abnormal CXR significantly predict MTB culture-positivity among smear-negative HIV-infected presumptive TB patients while previous TB treatment reduces the likelihood of a positive MTB culture. Validation studies to assess the performance of diagnostic algorithms that include urine TB-LAM in the diagnosis of smear-negative TB in HIV-infected individuals are warranted.

No MeSH data available.


Related in: MedlinePlus

A plot of a conditional inference tree showing the most predictive indictors for MTB culture-positivity.The model was fitted on the 381 participants with complete records.
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pone.0133756.g002: A plot of a conditional inference tree showing the most predictive indictors for MTB culture-positivity.The model was fitted on the 381 participants with complete records.

Mentions: Results of bivariate analysis are presented in Table 2. On multivariate logistic regression analysis (Table 2), presence of an abnormal CXR (aOR 3.68, 95% CI 1.76–7.71, p = 0.001) and a positive urine TB-LAM test (aOR 6.21, 95% CI 3.14–12.27, p< 0.001) were significantly associated with MTB culture-positivity among smear-negative HIV-infected presumptive TB patients. On the other hand, previous TB treatment (aOR 0.41, 95% CI 0.17–0.99, p = 0.049) reduced the likelihood of a positive TB culture. The conditional inference tree model to determine the ranking of the factors showed that the urine TB-LAM was the most predictive of MTB culture positivity, followed by a CXR in this cohort of patients based on Bonferroni-adjusted p-values (p<0.001 for urine TB-LAM and p = 0.004 for CXR). A plot of the fitted conditional inference tree (Fig 2). From the model, of the 52 participants that were declared positive by the urine TB-LAM test, 31(59.6%) were true MTB culture positives. Of the 329 participants that had been declared negative by urine TB-LAM test, the CXR found an additional 12 true MTB culture positives.


Predictors for MTB Culture-Positivity among HIV-Infected Smear-Negative Presumptive Tuberculosis Patients in Uganda: Application of New Tuberculosis Diagnostic Technology.

Nakiyingi L, Nonyane BA, Ssengooba W, Kirenga BJ, Nakanjako D, Lubega G, Byakika-Kibwika P, Joloba ML, Ellner JJ, Dorman SE, Mayanja-Kizza H, Manabe YC - PLoS ONE (2015)

A plot of a conditional inference tree showing the most predictive indictors for MTB culture-positivity.The model was fitted on the 381 participants with complete records.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519276&req=5

pone.0133756.g002: A plot of a conditional inference tree showing the most predictive indictors for MTB culture-positivity.The model was fitted on the 381 participants with complete records.
Mentions: Results of bivariate analysis are presented in Table 2. On multivariate logistic regression analysis (Table 2), presence of an abnormal CXR (aOR 3.68, 95% CI 1.76–7.71, p = 0.001) and a positive urine TB-LAM test (aOR 6.21, 95% CI 3.14–12.27, p< 0.001) were significantly associated with MTB culture-positivity among smear-negative HIV-infected presumptive TB patients. On the other hand, previous TB treatment (aOR 0.41, 95% CI 0.17–0.99, p = 0.049) reduced the likelihood of a positive TB culture. The conditional inference tree model to determine the ranking of the factors showed that the urine TB-LAM was the most predictive of MTB culture positivity, followed by a CXR in this cohort of patients based on Bonferroni-adjusted p-values (p<0.001 for urine TB-LAM and p = 0.004 for CXR). A plot of the fitted conditional inference tree (Fig 2). From the model, of the 52 participants that were declared positive by the urine TB-LAM test, 31(59.6%) were true MTB culture positives. Of the 329 participants that had been declared negative by urine TB-LAM test, the CXR found an additional 12 true MTB culture positives.

Bottom Line: New TB diagnostics such as urine TB lipoarabinomannan (LAM) could improve the accuracy and reduce delays in TB diagnosis in HIV-infected smear-negative presumptive TB.Abnormal CXR (aOR 3.68, 95% CI 1.76- 7.71, p=0.001) and positive urine TB-LAM (aOR 6.21, 95% CI 3.14-12.27, p< 0.001) were significantly associated with MTB culture-positivity.Validation studies to assess the performance of diagnostic algorithms that include urine TB-LAM in the diagnosis of smear-negative TB in HIV-infected individuals are warranted.

View Article: PubMed Central - PubMed

Affiliation: Infectious Diseases Institute, Makerere University College of Health Sciences, Kampala, Uganda; Department of Medicine, School of Medicine, Makerere University College of Heath Sciences, Kampala, Uganda.

ABSTRACT

Background: The existing World Health Organization diagnostic algorithms for smear-negative TB perform poorly in HIV-infected individuals. New TB diagnostics such as urine TB lipoarabinomannan (LAM) could improve the accuracy and reduce delays in TB diagnosis in HIV-infected smear-negative presumptive TB. We sought to determine predictors for MTB culture-positivity among these patients.

Methods: This study was nested into a prospective evaluation of HIV-infected outpatients and inpatients clinically suspected to have TB who were screened by smear-microscopy on two spot sputum samples. Data on socio-demographics, clinical symptoms, antiretroviral therapy, CXR, CD4 count, mycobacterial sputum and blood cultures and TB-LAM were collected. Logistic regression and conditional inference tree analysis were used to determine the most predictive indicators for MTB culture-positivity.

Results: Of the 418 smear-negative participants [female, 64%; median age (IQR) 32 (28-39) years, median CD4 106 (IQR 22 - 298) cells/mm3], 96/418 (23%) were sputum and/ or blood culture-positive for Mycobacterium tuberculosis (MTB) complex. Abnormal CXR (aOR 3.68, 95% CI 1.76- 7.71, p=0.001) and positive urine TB-LAM (aOR 6.21, 95% CI 3.14-12.27, p< 0.001) were significantly associated with MTB culture-positivity. Previous TB treatment (aOR 0.41, 95% CI 0.17-0.99, p=0.049) reduced the likelihood of a positive MTB culture. A conditional inference tree analysis showed that positive urine TB-LAM and abnormal CXR were the most predictive indicators of MTB culture-positivity. A combination of urine TB-LAM test and CXR had sensitivity and specificity of 50% and 86.1% respectively overall, and 70.8% and 84.1% respectively among those with CD4<100 cells/mm3.

Conclusions: A positive urine TB-LAM test and an abnormal CXR significantly predict MTB culture-positivity among smear-negative HIV-infected presumptive TB patients while previous TB treatment reduces the likelihood of a positive MTB culture. Validation studies to assess the performance of diagnostic algorithms that include urine TB-LAM in the diagnosis of smear-negative TB in HIV-infected individuals are warranted.

No MeSH data available.


Related in: MedlinePlus