Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

Supported by the Global Alliance for TB Drug Development with support from the Bill and Melinda Gates Foundation, the European and Developing Countries Clinical Trials Partnership (Grant IP.2007.32011.011), US Agency for International Development, UK Department for International Development, Directorate General for International Cooperation of the Netherlands, Irish Aid, Australia Department of Foreign Affairs and Trade, National Institutes of Health, AIDS Clinical Trials Group. The study was also supported by grants from the National Institute of Allergy and Infectious Diseases (NIAID) (UM1AI068634, UM1 AI068636, and UM1AI106701) and by NIAID grants to the University of KwaZulu Natal, South Africa, AIDS Clinical Trials Group (ACTG) site 31422 (1U01AI069469); to the Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, South Africa, ACTG site 12301 (1U01AI069453); and to the Durban International Clinical Trials Unit, South Africa, ACTG site 11201 (1U01AI069426). Bayer Healthcare for donated moxifloxacin and Sanofi donated rifampin.Background:  The use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment. Methods:  Patients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses. Results:  Data from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31 years (IQR 24–41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/μL (IQR 318–535). Pre-treatment spot samples had a higher yield of positive Ziehl–Neelsen smears (98% vs. 97%, P = 0.02) and LJ cultures (87% vs. 82%, P = 0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, P = 0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1 day, than spot samples in MGIT culture (4.5 vs. 5.5 days, P < 0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in Kaplan–Meier analyses in either EMS or spot samples. Conclusions:  Our data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples.Publisher PDFPeer reviewe

Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis.

BackgroundThe use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment.MethodsPatients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses.ResultsData from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31&nbsp;years (IQR 24-41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/μL (IQR 318-535). Pre-treatment spot samples had a higher yield of positive Ziehl-Neelsen smears (98% vs. 97%, P = 0.02) and LJ cultures (87% vs. 82%, P = 0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, P = 0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1&nbsp;day, than spot samples in MGIT culture (4.5 vs. 5.5&nbsp;days, P &lt; 0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in Kaplan-Meier analyses in either EMS or spot samples.ConclusionsOur data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples

Toxicity associated with tuberculosis chemotherapy in the REMoxTB study.

BackgroundThe incidence and severity of tuberculosis chemotherapy toxicity is poorly characterised. We used data available from patients in the REMoxTB trial to provide an assessment of the risks associated with the standard regimen and two experimental regimens containing moxifloxacin.MethodsAll grade 3 &amp; 4 adverse events (AEs) and their relationship to treatment for patients who had taken at least one dose of therapy in the REMoxTB clinical trial were recorded. Univariable logistic regression was used to test the relationship of baseline characteristics to the incidence of grade 3 &amp; 4 AEs and significant characteristics (p &lt; 0.10) were incorporated into a multivariable model. The timing of AEs during therapy was analysed in standard therapy and the experimental arms. Logistic regression was used to investigate the relationship between AEs (total and related-only) and microbiological cure on treatment.ResultsIn the standard therapy arm 57 (8.9%) of 639 patients experienced ≥1 related AEs with 80 of the total 113 related events (70.8%) occurring in the intensive phase of treatment. Both four-month experimental arms ("isoniazid arm" with moxifloxacin substituted for ethambutol &amp; "ethambutol arm" with moxifloxacin substituted for isoniazid) had a lower total of related grade 3 &amp; 4 AEs than standard therapy (63 &amp; 65 vs 113 AEs). Female gender (adjOR 1.97, 95% CI 0.91-1.83) and HIV-positive status (adjOR 3.33, 95% CI 1.55-7.14) were significantly associated with experiencing ≥1 related AE (p &lt; 0.05) on standard therapy. The most common adverse events on standard therapy related to hepatobiliary, musculoskeletal and metabolic disorders. Patients who experienced ≥1 related AE were more likely to fail treatment or relapse (adjOR 3.11, 95% CI 1.59-6.10, p &lt; 0.001).ConclusionsMost AEs considered related to standard therapy occurred in the intensive phase of treatment with female patients and HIV-positive patients demonstrating a significantly higher risk of AEs during treatment. Almost a tenth of standard therapy patients had a significant side effect, whereas both experimental arms recorded a lower incidence of toxicity. That patients with one or more AE are more likely to fail treatment suggests that treatment outcomes could be improved by identifying such patients through targeted monitoring