Understanding patient-level costs of weekly isoniazid-rifapentine (3HP) among people living with HIV in Uganda

BACKGROUND: Twelve weeks of weekly isoniazid and rifapentine (3HP) prevents TB disease among people with HIV (PWH), but the costs to people of taking TB preventive treatment is not well described.METHODS: We surveyed PWH who initiated 3HP at a large urban HIV/AIDS clinic in Kampala, Uganda, as part of a larger trial. We estimated the cost of one 3HP visit from the patient perspective, including both out-of-pocket costs and estimated lost wages. Costs were reported in 2021 Ugandan shillings (UGX) and US dollars (USD; USD1 = UGX3,587)RESULTS: The survey included 1,655 PWH. The median participant cost of one clinic visit was UGX19,200 (USD5.36), or 38.5% of the median weekly income. Per visit, the cost of transportation was the largest component (median: UGX10,000/USD2.79), followed by lost income (median: UGX4,200/USD1.16) and food (median: UGX2,000/USD0.56). Men reported greater income loss than women (median: UGX6,400/USD1.79 vs. UGX3,300/USD0.93), and participants who lived further than a 30-minute drive to the clinic had higher transportation costs than others (median: UGX14,000/USD3.90 vs. UGX8,000/USD2.23).CONCLUSION: Patient-level costs to receive 3HP accounted for over one-third of weekly income. Patient-centered approaches to averting or defraying these costs are needed.

Increase in rifampicin resistance among people previously treated for TB

People previously treated for TB are at a higher risk of rifampicin-resistant or multidrug-resistant TB (RR/MDR-TB). Uganda's recent RR-TB estimates were not updated, including during the COVID-19 pandemic. Using programmatic data (2012-2021), we report on the distribution and trends in RR-TB among people previously treated for bacteriologically confirmed pulmonary TB (BC-PTB) across six TB clinics in Kampala, Uganda. The RR-TB prevalence between 2012 and 2015 was 0% (95% CI 0-2.3). The prevalence rose significantly in recent years to 7.0% (95% CI 4.4-10.8) between 2016 and 2021 (P < 0.001). RR-TB is increasing among people previously treated for BC-PTB in Kampala; surveillance for RR-TB should be enhanced.

Gaps in TB preventive therapy for persons initiating antiretroviral therapy in Uganda: an explanatory sequential cascade analysis

BACKGROUND: The WHO recommends TB symptom screening and TB preventive therapy (TPT) for latent TB infection (LTBI) in persons living with HIV (PLWH). However, TPT uptake remains limited. We aimed to characterize and contextualize gaps in the TPT care cascade among persons enrolling for antiretroviral therapy (ART).SETTING: Four PEPFAR-supported facilities in Uganda.METHODS: We studied a proportionate stratified random sample of persons registering for ART when TPT was available. Patient-level data on eligibility, initiation, and completion were obtained from registers to determine proportion of eligible patients completing each cascade step. We interviewed providers and administrators and used content analysis to identify barriers to guideline-concordant TPT practices.RESULTS: Of 399 study persons, 309 (77%) were women. Median age was 29 (IQR 25-34), CD4 count 405 cells/µL (IQR 222-573), and body mass 23 kg/m² (IQR 21-25). Of 390 (98%) screened, 372 (93%) were TPT-eligible. Only 62 (17%) eligible PLWH initiated and 36 (58%) of 62 completed TPT. Providers reported hesitating to prescribe TPT because they lacked confidence excluding TB by symptom screening alone and feared promoting drug resistance. Although isoniazid was available, past experience of irregular supply discouraged TPT initiation. Providers pointed to insufficient TB-dedicated staff, speculated that patients discounted TB risk, and worried TPT pill burden and side effects depressed ART adherence.CONCLUSIONS: While screening was nearly universal, most eligible PLWH did not initiate TPT. Only about half of those who initiated completed treatment. Providers feared promoting drug resistance, harbored uncertainty about continued availability, and worried TPT could antagonize ART adherence. Our findings suggest urgent need for stakeholder engagement in TPT provision.

The transition to Xpert MTB/RIF ultra: diagnostic accuracy for pulmonary tuberculosis in Kampala, Uganda

BACKGROUND

The World Health Organization (WHO) has endorsed the next-generation Xpert MTB/RIF Ultra (Ultra) cartridge, and Uganda is currently transitioning from the older generation Xpert MTB/RIF (Xpert) cartridge to Ultra as the initial diagnostic test for pulmonary tuberculosis (TB). We assessed the diagnostic accuracy of Ultra for pulmonary TB among adults in Kampala, Uganda.

METHODS

We sampled adults referred for Xpert testing at two hospitals and a health center over a 12-month period. We enrolled adults with positive Xpert and a random 1:1 sample with negative Xpert results. Expectorated sputum was collected for Ultra, and for solid and liquid culture testing for Xpert-negative patients. We measured sensitivity and specificity of Ultra overall and by HIV status, prior history of TB, and hospitalization, in reference to Xpert and culture results. We also assessed how classification of results in the new "trace" category affects Ultra accuracy.

RESULTS

Among 698 participants included, 211 (30%) were HIV-positive and 336 (48%) had TB. The sensitivity of Ultra was 90.5% (95% CI 86.8-93.4) and specificity was 98.1% (95% CI 96.1-99.2). There were no significant differences in sensitivity and specificity by HIV status, prior history of TB or hospitalization. Xpert and Ultra results were concordant in 670 (96%) participants, with Ultra having a small reduction in specificity (difference 1.9, 95% CI 0.2 to 3.6, p=0.01). When "trace" results were considered positive for all patients, sensitivity increased by 2.1% (95% CI 0.3 to 3.9, p=0.01) without a significant reduction in specificity (- 0.8, 95% CI - 0.3 to 2.0, p=0.08).

CONCLUSIONS

After 1 year of implementation, Ultra had similar performance to Xpert. Considering "trace" results to be positive in all patients increased case detection without significant loss of specificity. Longitudinal studies are needed to compare the benefit of greater diagnoses to the cost of overtreatment.

Quality of care in childhood tuberculosis diagnosis at primary care clinics in Kampala, Uganda

OBJECTIVE

To assess the quality of routine childhood tuberculosis (TB) evaluation in Kampala, Uganda.

SETTING AND DESIGN

This was a cross-sectional study of children aged <15 years attending six government-run clinics from November 2015 to December 2016. Clinicians completed a standardized patient record form for all child visits. We assessed the following performance indicators of TB evaluation developed based on the Desk Guide of the International Union Against Tuberculosis and Lung Disease, an evidence-based decision aid on childhood TB diagnosis and management for clinicians: proportion screened for TB symptoms or contact history, proportion referred for laboratory evaluation if screen-positive, and proportion treated for TB if test-positive or meeting clinical criteria.

RESULTS

Of 24 566 consecutive children enrolled, 11 614 (47%) were fully screened for TB symptoms. Of 1747 (15%) children who screened positive, 360 (21%) had sputum examined, including 159 (44%) using smear microscopy, 244 (67%) using Xpert® MTB/RIF, and 52 (14%) using both techniques. Treatment was initiated in 18/20 (80%) children who tested positive. An additional 65 screen-positive children met the clinical criteria for TB; none were initiated on treatment.

CONCLUSIONS

Large gaps exist along the pathway to diagnosis and treatment of childhood TB. There is an urgent need for enhanced implementation of evidence-based approaches to TB diagnosis to improve outcomes in childhood TB.

'Something so hard': a mixed-methods study of home sputum collection for tuberculosis contact investigation in Uganda

BACKGROUND

Home sputum collection could facilitate prompt evaluation and diagnosis of tuberculosis (TB) among contacts of patients with active TB. We analyzed barriers to home-based collection as part of an enhanced intervention for household TB contact investigation in Kampala, Uganda.

DESIGN

We conducted a convergent mixed-methods study to describe the outcomes of home sputum collection in 91 contacts and examine their context through 19 nested contact interviews and two focus group discussions with lay health workers (LHWs).

RESULTS

LHWs collected sputum from 35 (39%) contacts. Contacts reporting cough were more likely to provide sputum than those with other symptoms or risk factors (53% vs. 15%, RR 3.6, 95%CI 1.5-2.8, P < 0.001). Males were more likely than females to provide sputum (54% vs. 32%, RR 1.7, 95%CI 1.0-2.8, P = 0.05). Contacts said support from the index patient and the convenience of the home visit facilitated collection. Missing containers and difficulty producing sputum spontaneously impeded collection. Women identified stigma as a barrier. LHWs emphasized difficulty in procuring sputum and discomfort pressing contacts to produce sputum.

CONCLUSIONS

Home sputum collection by LHWs entails different challenges from sputum collection in clinical settings. More research is needed to develop interventions to mitigate stigma and increase success of home-based collection.

Accuracy and incremental yield of urine Xpert MTB/RIF Ultra versus Determine TB-LAM for diagnosis of pulmonary tuberculosis

The performance of urine Xpert MTB/RIF Ultra (Xpert Ultra) for pulmonary TB diagnosis is unknown. HIV-positive and HIV-negative adults were enrolled at two health facilities in Kampala, Uganda. We compared the accuracy of urine Xpert Ultra and Determine TB-LAM in reference to sputum-based testing (positive Xpert MTB/RIF or culture), and assessed incremental yield. Urine Xpert Ultra had low sensitivity (17.2%, 95% CI 12.3-23.2) but high specificity (98.1%, 95% CI 94.4-99.6). Sensitivity reached 50.0% (95% CI 28.2-71.8) among HIV-positive patients with CD4 <100 cells/μL. Compared to Determine TB-LAM, urine Xpert Ultra was 9.4% (95% CI 3.8-14.9, P = 0.01) more sensitive, and 17.2% (95% CI 4.5-29.8, P = 0.01) more sensitive among HIV-positive patients. However, the incremental sensitivity of urine Xpert Ultra relative to sputum Xpert MTB/RIF was only 1% (95% CI -0.9 to 2.8). Urine Xpert Ultra could be an alternative for patients with advanced HIV infection unable to produce sputum.

Patterns of usage and preferences of users for tuberculosis-related text messages and voice calls in Uganda

BACKGROUND

Little information exists about mobile phone usage or preferences for tuberculosis (TB) related health communications in Uganda.

METHODS

We surveyed household contacts of TB patients in urban Kampala, Uganda, and clinic patients in rural central Uganda. Questions addressed mobile phone access, usage, and preferences for TB-related communications. We collected qualitative data about messaging preferences.

RESULTS

We enrolled 145 contacts and 203 clinic attendees. Most contacts (58%) and clinic attendees (75%) owned a mobile phone, while 42% of contacts and 10% of clinic attendees shared one; 94% of contacts and clinic attendees knew how to receive a short messaging service (SMS) message, but only 59% of contacts aged 45 years (vs. 96% of contacts aged <45 years, P = 0.0001) did so. All contacts and 99% of clinic attendees were willing and capable of receiving personal-health communications by SMS. Among contacts, 55% preferred detailed messages disclosing test results, while 45% preferred simple messages requesting a clinic visit to disclose results.

CONCLUSIONS

Most urban household TB contacts and rural clinic attendees reported having access to a mobile phone and willingness to receive TB-related personal-health communications by voice call or SMS. However, frequent phone sharing and variable messaging abilities and preferences suggest a need to tailor the design and monitoring of mHealth interventions to target recipients.

Identifying Barriers to Physical Activity Among African American Women with Asthma

OBJECTIVE

African American Women (AAW) are disproportionately impacted by both physical inactivity and asthma. The aims of this study were to: 1) understand barriers to physical activity among AAW with asthma; 2) obtain feedback from AAW on an evidence-based walking intervention; and 3) modify the intervention using input from AAW with asthma.

METHODS

Focus groups and interviews were conducted with sedentary AAW with uncontrolled asthma to identify barriers to walking. Women also suggestions for tailoring an existing walking intervention. Qualitative data were coded using domains from the Behavior Change Wheel and guided modifications of the existing walking intervention to tailor the content for sedentary AAW with asthma.

RESULTS

Six focus groups (2-4 /group) and five interviews were completed. Women (n=20) represented an obese (37 kg/m2 ± 11), middle-aged (46 years ± 15) and low-income population. Barriers to physical activity were mapped to 8 theoretical domains: 1) Limited physical capability; 2) Lack of knowledge; 3) Lack of self-monitoring skills; 4) Complex decision making processes; 5) Lack of areas to walk; 6) Lack of social support; 7) Beliefs about consequences; 8) Beliefs about capability. To target these barriers, the existing walking intervention was modified to include an asthma education session, text messages, monthly group meetings, a walking session and informational materials.

CONCLUSION

AAW with asthma reported unique barriers to engaging in physical activity. An assessment of the feasibility, acceptability and efficacy of a modified intervention that addresses these barriers is warranted to address physical inactivity and poor asthma outcomes among AAW with asthma.

Feasibility of a streamlined tuberculosis diagnosis and treatment initiation strategy

OBJECTIVE:

To assess the feasibility of a streamlined strategy for improving tuberculosis (TB) diagnostic evaluation and treatment initiation among patients with presumed TB.

DESIGN:

Single-arm interventional pilot study at five primary care health centers of a streamlined, SIngle-saMPLE (SIMPLE) TB diagnostic evaluation strategy: 1) examination of two smear results from a single spot sputum specimen using light-emitting diode fluorescence microscopy, and 2) daily transportation of smear-negative sputum samples to Xpert® MTB/RIF testing sites.

RESULTS:

Of 1212 adults who underwent sputum testing for TB, 99.6% had two smears examined from the spot sputum specimen. Sputum was transported for Xpert testing within 1 clinic day for 83% (907/1091) of the smear-negative patients. Of 157 (13%) patients with bacteriologically positive TB, 116 (74%) were identified using sputum smear microscopy and 41 (26%) using Xpert testing of smear-negative samples. Anti-tuberculosis treatment was initiated in 142 (90%) patients with bacteriologically positive TB, with a median time to treatment of 1 day for smear-positive patients and 6 days for smear-negative, Xpert-positive patients.

CONCLUSION:

The SIMPLE TB strategy led to successful incorporation of Xpert testing and rapid treatment initiation in the majority of patients with bacteriologically confirmed TB in a resource-limited setting.

Higher cost of implementing Xpert(®) MTB/RIF in Ugandan peripheral settings: implications for cost-effectiveness

SETTING

Initial cost-effectiveness evaluations of Xpert(®) MTB/RIF for tuberculosis (TB) diagnosis have not fully accounted for the realities of implementation in peripheral settings.

OBJECTIVE

To evaluate costs and diagnostic outcomes of Xpert testing implemented at various health care levels in Uganda.

DESIGN

We collected empirical cost data from five health centers utilizing Xpert for TB diagnosis, using an ingredients approach. We reviewed laboratory and patient records to assess outcomes at these sites and10 sites without Xpert. We also estimated incremental cost-effectiveness of Xpert testing; our primary outcome was the incremental cost of Xpert testing per newly detected TB case.

RESULTS

The mean unit cost of an Xpert test was US$21 based on a mean monthly volume of 54 tests per site, although unit cost varied widely (US$16-58) and was primarily determined by testing volume. Total diagnostic costs were 2.4-fold higher in Xpert clinics than in non-Xpert clinics; however, Xpert only increased diagnoses by 12%. The diagnostic costs of Xpert averaged US$119 per newly detected TB case, but were as high as US$885 at the center with the lowest volume of tests.

CONCLUSION

Xpert testing can detect TB cases at reasonable cost, but may double diagnostic budgets for relatively small gains, with cost-effectiveness deteriorating with lower testing volumes.

Treatment of non-cavitary pulmonary tuberculosis with shortened fluoroquinolone-based regimens: a meta-analysis

SETTING

Several recent trials evaluating 4-month fluoroquinolone (FQ) containing regimens found that none of the experimental regimens were non-inferior to standard 6-month therapy in treating patients with drug-susceptible pulmonary tuberculosis (PTB).

OBJECTIVE

To answer whether FQ-containing duration-shortened regimens are non-inferior to standard therapy in the treatment of patients with non-cavitary PTB.

DESIGN

Systematic review of all randomized and quasi-randomized trials that substituted an FQ into standard therapy for less than 6 months' duration to treat drug-susceptible, non-cavitary PTB. Non-inferiority was based on a 6% margin of difference.

RESULTS

Of 4594 total participants in the three trials that met the inclusion criteria, 1066 patients had non-cavitary disease. The pooled difference in unfavorable outcomes was 5% (95%CI -3 to 13) in patients with non-cavitary disease treated with FQ-containing regimens vs. standard therapy. In subgroup analyses, the pooled difference in unfavorable outcomes was 1% (95%CI -3 to 5) when comparing the daily form of intervention regimen with standard therapy, and -1% (95%CI -5 to 4) between regimens replacing ethambutol (EMB) with an FQ and standard therapy. No difference in risk of adverse events was noted.

CONCLUSION

Daily administered 4-month regimens with substitution of EMB by an FQ may be non-inferior to standard therapy in patients with culture-confirmed, non-cavitary, drug-susceptible PTB.

The sixth vital sign: HIV status assessment and severe illness triage in Uganda

Setting: Four in-patient health facilities in western Uganda. Objective: To determine the impact of an innovative multi-modal quality improvement program on human immunodeficiency virus (HIV) status assessment and the impact of HIV status on severe illness conditions and mortality. Design: This was a staggered, pre-post quasi-experimental study designed to assess a multi-modal intervention (collaborative improvement meetings, audit and feedback, clinical mentoring) for improving quality of care following formal training in the management of severe illness in low-income settings. Results: From August 2014 to May 2015, 5759 patients were hospitalized, of whom 2451 (42.6%) had their HIV status assessed; 395 (16.1%) were HIV-infected. HIV-infected patients were significantly more likely to meet criteria for shock (27.5% vs. 15.1%, risk ratio [RR] 1.8, 95% confidence interval [CI] 1.7-1.9, P < 0.001) and severe respiratory distress (6.7% vs. 4.3%, RR 1.5, 95%CI 1.2-2.0, P < 0.001), and were significantly more likely to die in hospital (12.0% vs. 2.9%, RR 4.1, 95%CI 3.2-5.4, P < 0.001). There was no evidence of improved HIV status assessment during the intervention period (36.5% vs. 44.8%, +8.3%, 95%CI -8.3 to 24.8, P = 0.33). Conclusions: Hospitalized HIV-infected patients in western Uganda are at high risk for severe illness and death. Novel quality improvement strategies are needed to enhance hospital-based HIV testing in high-burden settings.

Evaluation of mobile digital light-emitting diode fluorescence microscopy in Hanoi, Viet Nam

SETTING

Hanoi Lung Hospital, Hanoi, Viet Nam.

OBJECTIVE

To compare the accuracy of CellScopeTB, a manually operated mobile digital fluorescence microscope, with conventional microscopy techniques.

DESIGN

Patients referred for sputum smear microscopy to the Hanoi Lung Hospital from May to September 2013 were included. Ziehl-Neelsen (ZN) smear microscopy, conventional light-emitting diode (LED) fluorescence microscopy (FM), CellScopeTB-based LED FM and Xpert(®) MTB/RIF were performed on sputum samples. The sensitivity and specificity of microscopy techniques were determined in reference to Xpert results, and differences were compared using McNemar's paired test of proportions.

RESULTS

Of 326 patients enrolled, 93 (28.5%) were Xpert-positive for TB. The sensitivity of ZN microscopy, conventional LED FM, and CellScopeTB-based LED FM was respectively 37.6% (95%CI 27.8-48.3), 41.9% (95%CI 31.8-52.6), and 35.5% (95%CI 25.8-46.1). The sensitivity of CellScopeTB was similar to that of conventional LED FM (difference -6.5%, 95%CI -18.2 to 5.3, P = 0.33) and ZN microscopy (difference -2.2%, 95%CI -9.2 to 4.9, P = 0.73). The specificity was >99% for all three techniques.

DISCUSSION

CellScopeTB performed similarly to conventional microscopy techniques in the hands of experienced TB microscopists. However, the sensitivity of all sputum microscopy techniques was low. Options enabled by digital microscopy, such as automated imaging with real-time computerized analysis, should be explored to increase sensitivity.

Pathways and costs of care for patients with tuberculosis symptoms in rural Uganda

SETTING

Six district-level government health centers in rural Uganda and the surrounding communities.

OBJECTIVE

To determine pathways to care and associated costs for patients with chronic cough referred for tuberculosis (TB) evaluation in Uganda.

DESIGN

We conducted a cross-sectional study, surveying 64 patients presenting with chronic cough and undergoing first-time sputum evaluation at government clinics. We also surveyed a random sample of 114 individuals with chronic cough in surrounding communities. We collected information on previous health visits for the cough as well as costs associated with the current visit.

RESULTS

Eighty per cent of clinic patients had previously sought care for their cough, with a median of three previous visits (range 0-32, interquartile range [IQR] 2-5). Most (n = 203, 88%) visits were to a health facility that did not provide TB microscopy services, and the majority occurred in the private sector. The cost of seeking care for the current visit alone represented 28.8% (IQR 9.1-109.5) of the patients' median monthly household income.

CONCLUSION

Most patients seek health care for chronic cough, but do so first in the private sector. Engagement of the private sector and streamlining TB diagnostic evaluation are critical for improving case detection and meeting global TB elimination targets.

Quality of tuberculosis care in India: a systematic review

BACKGROUND

While Indian studies have assessed care providers' knowledge and practices, there is no systematic review on the quality of tuberculosis (TB) care.

METHODS

We searched multiple sources to identify studies (2000-2014) on providers' knowledge and practices. We used the International Standards for TB Care to benchmark quality of care.

RESULTS

Of the 47 studies included, 35 were questionnaire surveys and 12 used chart abstraction. None assessed actual practice using standardised patients. Heterogeneity in the findings precluded meta-analysis. Of 22 studies evaluating provider knowledge about using sputum smears for diagnosis, 10 found that less than half of providers had correct knowledge; 3 of 4 studies assessing self-reported practices by providers found that less than a quarter reported ordering smears for patients with chest symptoms. In 11 of 14 studies that assessed treatment, less than one third of providers knew the standard regimen for drug-susceptible TB. Adherence to standards in practice was generally lower than correct knowledge of those standards. Eleven studies with both public and private providers found higher levels of appropriate knowledge/practice in the public sector.

CONCLUSIONS

Available evidence suggests suboptimal quality of TB care, particularly in the private sector. Improvement of quality of care should be a priority for India.

Identifying multidrug resistance in previously treated tuberculosis patients: a mixed-methods study in Cambodia

SETTING

Previously treated tuberculosis (TB) patients are a priority for drug susceptibility testing (DST) to identify cases with multidrug-resistant TB (MDR-TB). A Cambodia study found that one third of smear-positive previously treated patients had DST results.

OBJECTIVE

To quantify the gaps in the detection of MDR-TB in previously treated TB patients in Cambodia, and describe health workers' perspectives on barriers, facilitators and potential interventions.

DESIGN

Analysis of Cambodia's 2004-2012 case notifications and semi-structured interviews with stakeholders.

RESULTS

The proportion of previously treated notifications varied significantly across provinces in 2010-2012. If there had been no attrition along the path to detecting MDR-TB among smear-positive notified cases in 2012, an estimated 75 additional MDR-TB cases could have been identified, which would double the number actually detected. Most were lost due to misclassification of previously treated patients as 'new'. Barriers include patients' reluctance to disclose and staff difficulty in eliciting treatment history, partly attributed to the availability of streptomycin (SM) only in hospitals. Facilitators include collection of sputum for DST even if previously treated patients are not receiving SM, streamlining sputum transportation and prompt reporting of results.

CONCLUSION

Improved monitoring, supportive staff supervision and training, patient education, and correct classification of previously treated cases are essential for improving the detection of MDR-TB.

Impact of mycobacterial culture among HIV-infected adults with presumed TB in Uganda: a prospective cohort study

BACKGROUND

Implementation of new tuberculosis (TB) diagnostic strategies in resource-constrained settings is challenging. We measured the impact of solid and liquid mycobacterial cultures on treatment practices for patients undergoing TB evaluation in Kampala, Uganda.

METHODS

We enrolled consecutive smear-negative, human immunodeficiency virus positive adults with cough of ⩾2 weeks from September 2009 to April 2010. Laboratory technicians performed mycobacterial cultures on solid and liquid media. We compared empiric treatment decisions with solid and liquid culture in terms of diagnostic yield and time to results, and assessed impact on patient management.

RESULTS

Of 200 patients enrolled, 26 (13%) had culture-confirmed TB: 22 (85%) on solid culture alone, 2 (8%) on liquid culture alone, and 2 (8%) on both solid and liquid culture. Thirty-four patients received empiric anti-tuberculosis treatment, but only 10 (29%) were culture-positive. Median time to a positive result on solid culture was 92 days (interquartile range [IQR] 69-148) compared to 106 days (IQR 66-157) for liquid culture. No patients initiated treatment following a positive result on liquid culture.

CONCLUSION

The introduction of mycobacterial culture did not influence care for patients undergoing evaluation for TB in Kampala, Uganda. Attention to contextual factors surrounding implementation is needed to ensure the effective introduction of new testing strategies in low-income countries.

Sex disparities in tuberculosis suspect evaluation: a cross-sectional analysis in rural Uganda

SETTING

Six primary health care centers in rural Uganda.

OBJECTIVE

To compare the quality of tuberculosis (TB) evaluation for men and women presenting to primary health care facilities in high-burden settings.

DESIGN

Cross-sectional study using indicators derived from the International Standards of Tuberculosis Care (ISTC) to compare the quality of TB evaluation services provided to men and women.

RESULTS

Of 161 230 patient visits between January 2009 and December 2010, 112 329 (69.7%) were women. We considered 3308 (2.1%) patients with cough ≥2 weeks as TB suspects, of whom 1871 (56.6%) were women. Female TB suspects were less likely to be referred for sputum smear examination (45.9% vs. 61.6%, P < 0.001), to complete sputum smear examination if referred (73.7% vs. 78.3%, P = 0.024) and to receive comprehensive evaluation and care as defined by the ISTC (33.0% vs. 45.6%, P < 0.001). After adjusting for age, clinic site and visit date, women remained less likely to be referred for sputum smear examination (risk ratio [RR] 0.81, 95%CI 0.74-0.89, P < 0.001) and to receive ISTC-recommended care (RR 0.79, 95%CI 0.72-0.86, P < 0.001).

CONCLUSION

Strategies to ensure that women receive appropriate TB evaluation could provide a valuable opportunity for increasing case detection while also promoting equitable and universal access to care.

Chest radiographic findings of pulmonary tuberculosis in severely immunocompromised patients with the human immunodeficiency virus

OBJECTIVE

We describe chest radiograph (CXR) findings in a population with a high prevalence of human immunodeficiency virus (HIV) and tuberculosis (TB) in order to identify radiological features associated with TB; to compare CXR features between HIV-seronegative and HIV-seropositive patients with TB; and to correlate CXR findings with CD4 T-cell count.

METHODS

Consecutive adult patients admitted to a national referral hospital with a cough of duration of 2 weeks or longer underwent diagnostic evaluation for TB and other pneumonias, including sputum examination and mycobacterial culture, bronchoscopy and CXR. Two radiologists blindly reviewed CXRs using a standardised interpretation form.

RESULTS

Smear or culture-positive TB was diagnosed in 214 of 403 (53%) patients. Median CD4+ T-cell count was 50 cells mm(-3) [interquartile range (IQR) 14-150]. TB patients were less likely than non-TB patients to have a normal CXR (12% vs 20%, p = 0.04), and more likely than non-TB patients to have a diffuse pattern of opacities (75% vs 60%, p = 0.003), reticulonodular opacities (45% vs 12%, p < 0.001), nodules (14% vs 6%, p = 0.008) or cavities (18% vs 7%, p = 0.001). HIV-seronegative TB patients more often had consolidation (70% vs 42%, p = 0.007) and cavities (48% vs 13%, p < 0.001) than HIV-seropositive TB patients. TB patients with a CD4+ T-cell count of ≤ 50 cells mm(-3) less often had consolidation (33% vs 54%, p = 0.006) and more often had hilar lymphadenopathy (30% vs 16%, p = 0.03) compared with patients with CD4 51-200 cells mm(-3).

CONCLUSION

Although different CXR patterns can be seen in TB and non-TB pneumonias there is considerable overlap in features, especially among HIV-seropositive and severely immunosuppressed patients. Providing clinical and immunological information to the radiologist might improve the accuracy of radiographic diagnosis of TB.

Sensitivity and specificity of fluorescence microscopy for diagnosing pulmonary tuberculosis in a high HIV prevalence setting

SETTING

Mulago Hospital, Kampala, Uganda.

OBJECTIVE

To evaluate the diagnostic performance of fluorescence microscopy (FM) for diagnosing pulmonary tuberculosis (TB) in a high human immunodeficiency virus (HIV) prevalence setting.

DESIGN

Consecutive in-patients with cough for >2 weeks submitted two sputum specimens for smear microscopy. Smears were examined by conventional light microscopy (CM) and FM. The performance of the two methods was compared using mycobacterial culture as a reference standard.

RESULTS

A total of 426 patients (82% HIV-infected) were evaluated. FM identified 11% more smear-positive patients than CM (49% vs. 38%, P < 0.001). However, positive FM results were less likely than positive CM results to be confirmed by culture when smears were read as either 'scanty' (54% vs. 90%, P < 0.001) or 1+ (82% vs. 91%, P = 0.02). Compared to CM, the sensitivity of FM was higher (72% vs. 64%, P = 0.005), and the specificity lower (81% vs. 96%, P < 0.001). In receiver operating characteristic analysis, maximum area under the curve for FM was obtained at a threshold of >4 acid-fast bacilli/100 fields (sensitivity 68%, specificity 90%).

CONCLUSION

Although FM increases the sensitivity of sputum smear microscopy, additional data on FM specificity and on the clinical consequences associated with false-positive FM results are needed to guide implementation of this technology in high HIV prevalence settings.

A 13-year molecular epidemiological analysis of tuberculosis in San Francisco

BACKGROUND

We examined the molecular epidemiology of tuberculosis (TB) in San Francisco during a 13-year period encompassing the peak of TB resurgence and subsequent decline to historic low levels.

OBJECTIVE

To compare rates of TB caused either by rapid progression of recent Mycobacterium tuberculosis infection or by reactivation of latent infection.

METHODS

All TB cases reported from 1991 to 2003 were included. Genotyping was performed to identify clustered cases.

RESULTS

The annual TB case rate decreased significantly from 50.8 to 28.8 cases/100000 persons from 1992 to 1999 (P < 0.0001). After 1999, no significant decrease was observed for the population as a whole or in any subgroup examined. Similarly, the rate of clustered cases decreased significantly from 1992 to 1999 (11.4 to 3.1 cases/100000, P < 0.0001). Although the rate of non-clustered cases also declined significantly (25.6 to 17.6 cases/100,000, P < 0.0001), there was a disproportionate reduction in clustered cases (94.7% vs. 50.8%, P < 0.0001). Neither clustered nor non-clustered cases decreased significantly after 1999.

CONCLUSIONS

TB case rates reached a plateau despite ongoing application of control measures implemented in 1993. These data suggest that intensification of measures designed to identify and treat persons with latent TB infection will be necessary to further reduce TB incidence.

Mycobacterium tuberculosis inhibits IFN-gamma transcriptional responses without inhibiting activation of STAT1

IFN-gamma activates macrophages to kill diverse intracellular pathogens, but does not activate human macrophages to kill virulent Mycobacterium tuberculosis. We tested the hypothesis that this is due to inhibition of IFN-gamma signaling by M. tuberculosis and found that M. tuberculosis infection of human macrophages blocks several responses to IFN-gamma, including killing of Toxoplasma gondii and induction of FcgammaRI. The inhibitory effect of M. tuberculosis is directed at transcription of IFN-gamma-responsive genes, but does not affect proximal steps in the Janus kinase-STAT pathway, as STAT1alpha tyrosine and serine phosphorylation, dimerization, nuclear translocation, and DNA binding are intact in M. tuberculosis-infected cells. In contrast, there is a marked decrease in IFN-gamma-induced association of STAT1 with the transcriptional coactivators CREB binding protein and p300 in M. tuberculosis-infected macrophages, indicating that M. tuberculosis directly or indirectly disrupts this protein-protein interaction that is essential for transcriptional responses to IFN-gamma. Gamma-irradiated M. tuberculosis and isolated cell walls reproduce the effects of live bacteria, indicating that the bacterial component(s) that initiates inhibition of IFN-gamma responses is constitutively expressed. Although lipoarabinomannan has been found to exert effects on macrophages, it does not account for the inhibitory effects of cell walls. These results indicate that one mechanism for M. tuberculosis to evade the human immune response is to inhibit the IFN-gamma signaling pathway, and that the mechanism of inhibition is distinct from that reported for Leishmania donovani or CMV, in that it targets the interaction of STAT1 with the basal transcriptional apparatus.

CTLA4Ig inhibits airway eosinophilia and hyperresponsiveness by regulating the development of Th1/Th2 subsets in a murine model of asthma

Complete T-cell activation requires two distinct signals, one delivered via the T-cell receptor, and the second "co-stimulatory" signal through CD28/B7 ligation. Previous studies showed that the blockade of CD28/B7 ligation alters differentiation of Th1/Th2 lymphocyte subsets in vitro and in vivo. The present study was designed to determine the effect of a CD28/B7 antagonist (CTLA4Ig) on Th1/Th2 development in Schistosoma mansoni-sensitized and airway-challenged mice. Treatment of mice with CTLA4Ig beginning 1 wk after sensitization abolished airway responsiveness to intravenous methacholine determined 96 h following antigen challenge. We also found a significant reduction in bronchoalveolar lavage (BAL) eosinophilia, and reduced peribronchial eosinophilic infiltration and mucoid-cell hyperplasia. Furthermore, CTLA4Ig treatment significantly decreased interleukin (IL)-4 and IL-5 content in BAL fluid in vivo, and the production of IL-5 by lung lymphocytes stimulated with soluble egg antigen (SEA) in vitro. In contrast, the content of interferon-gamma in BAL fluid and supernatant from SEA-stimulated lung lymphocytes from CTLA4Ig-treated mice was increased significantly compared with untreated animals. Thus, CTLA4Ig inhibits eosinophilic airway inflammation and airway hyperresponsiveness in S. mansoni-sensitized and airway-challenged mice, most likely due to attenuated secretion of Th2-type cytokines and increased secretion of Th1-type cytokines.