Classification and regression tree (CART) model to predict pulmonary tuberculosis in hospitalized patients

Background: Tuberculosis (TB) remains a public health issue worldwide. The lack of specific clinical symptoms to diagnose TB makes the correct decision to admit patients to respiratory isolation a difficult task for the clinician. Isolation of patients without the disease is common and increases health costs. Decision models for the diagnosis of TB in patients attending hospitals can increase the quality of care and decrease costs, without the risk of hospital transmission. We present a predictive model for predicting pulmonary TB in hospitalized patients in a high prevalence area in order to contribute to a more rational use of isolation rooms without increasing the risk of transmission. Methods: Cross sectional study of patients admitted to CFFH from March 2003 to December 2004. A classification and regression tree (CART) model was generated and validated. The area under the ROC curve (AUC), sensitivity, specificity, positive and negative predictive values were used to evaluate the performance of model. Validation of the model was performed with a different sample of patients admitted to the same hospital from January to December 2005. Results: We studied 290 patients admitted with clinical suspicion of TB. Diagnosis was confirmed in 26.5% of them. Pulmonary TB was present in 83.7% of the patients with TB (62.3% with positive sputum smear) and HIV/AIDS was present in 56.9% of patients. The validated CART model showed sensitivity, specificity, positive predictive value and negative predictive value of 60.00%, 76.16%, 33.33%, and 90.55%, respectively. The AUC was 79.70%. Conclusions: The CART model developed for these hospitalized patients with clinical suspicion of TB had fair to good predictive performance for pulmonary TB. The most important variable for prediction of TB diagnosis was chest radiograph results. Prospective validation is still necessary, but our model offer an alternative for decision making in whether to isolate patients with clinical suspicion of TB in tertiary health facilities in countries with limited resources.

DELAY IN THE DIAGNOSIS OF TUBERCULOSIS IN PRISONS: THE EXPERIENCE OF INCARCERATED PATIENTS

This study analyzed the causes of delay in the diagnosis of tuberculosis in the prison system, according to the experience of incarcerated patients. The theoretical and methodological framework of the French school of discourse analysis was used, which seeks to comprehend the processes of meaning production, in the relationship of language with ideology and the development of subjects in their positions. Semi-directed interviews were conducted with seven incarcerated tuberculosis patients in a hospital of Joao Pessoa, Paraiba, Brazil, between August and October 2009. The delay in the diagnosis of tuberculosis was related to the naturalization of the lack of care for the prisoner, to the interpretation of the prison as a place of death and suffering and to the deprivation of the right to health for the detainees as a result of their position in the asymmetric power relationships and ideological effects.

Delay in the search for health services for the diagnosis of tuberculosis in Ribeirao Preto, Sao Paulo

The scope of this paper is to analyze delays in locating health services for the diagnosis of tuberculosis in Ribeirao Preto in 2009. An epidemiological and cross-sectional study was conducted with 94 TB patients undergoing treatment. A structured questionnaire, based on the Primary Care Assessment Tool adapted for TB care was used. A median (15 days or more) was established to characterize delay in health attendance. Using the Prevalence Ratio, the variables associated with longer delay were identified. The first healthcare services sought were the Emergency Services (ES) (57.5%). The longest period between seeking assistance occurred among males, aged between 50 and 59, who earned less than five minimum wages, had pulmonary TB, were new cases, were not co-infected with TB/HIV, did not consume alcohol, had satisfactory knowledge about TB before diagnosis (with a statistically significant association with delay) and who did not seek healthcare close to home before developing TB. There is a perceived need for training healthcare professionals about the signs and symptoms of the disease, reducing barriers of access to timely diagnosis of TB and widely disseminating it to the community in general.

Delays in the diagnosis of tuberculosis in a town at the triple border of Brazil, Paraguay, and Argentina

Objective. To identify the factors linked to patients and health services in delays in the diagnosis of tuberculosis. Methods. Epidemiological study in Foz do Iguacu, Parana, Brazil, 2009. The Primary Care Assessment Tool, adapted for appraising tuberculosis treatment, was the instrument used. Descriptive statistics techniques were used, such as frequency distributions, central tendency and dispersion measurements (median and interquartile intervals), and odds ratios. Results. There were greater delays in seeking health services for those in the age group 60 years and older, for females, for patients with low levels of education, and for patients with poor knowledge of the disease. Clinical variables (being a new case and HIV infection) and behavioral variables (use of tobacco and alcohol consumption) were not linked with delays in diagnosis. The median time delays before diagnosis attributable to patients and to the health services were 30 days and 10 days, respectively. Emergency 24-hour medical services and primary health care services were not effective in identifying suspicious cases of tuberculosis and requesting tests to confirm the diagnosis, with a high percentage of referrals to the Tuberculosis Control Program clinic. Conclusions. Going to primary health care services for diagnosis increased the time before diagnosis of the disease was reached. The Tuberculosis Control Program clinic was more effective in diagnosis of tuberculosis, due to the training of the staff and to an organized process for receiving patients, including the availability of tests to support the diagnosis.

Bronchoscopy for the diagnosis of pulmonary tuberculosis in patients with negative sputum smear microscopy results

Objective: To evaluate the diagnostic accuracy of bronchoscopy in patients with clinical or radiological suspicion of tuberculosis who were unable to produce sputum or with negative sputum smear microscopy results. Methods: A prospective cross-sectional study involving 286 patients under clinical or radiological suspicion of having pulmonary tuberculosis and submitted to bronchoscopy-BAL and transbronchial biopsy (TBB). The BAL specimens were submitted to direct testing and culture for AFB and fungi, whereas the TBB specimens were submitted to histopathological examination. Results: Of the 286 patients studied, 225 (79%) were diagnosed on the basis of bronchoscopic findings, as follows: pulmonary tuberculosis, in 127 (44%); nonspecific chronic inflammation, in 51 (18%); pneumocystis, fungal infections, or nocardiosis, in 20 (7%); bronchiolitis obliterans organizing pneumonia, alveolites, or pneumoconiosis, in 14 (5%); lung or metastatic neoplasms, in 7 (2%); and nontuberculous mycobacterium infections, in 6 (2%). For the diagnosis of tuberculosis, BAL showed a sensitivity and a specificity of 60% and 100%, respectively. Adding the TBB findings significantly increased this sensitivity (to 84%), as did adding the post-bronchoscopy sputum smear microscopy results (total sensitivity, 94%). Minor post-procedure complications occurred in 5.6% of the cases. Conclusions: Bronchoscopy is a reliable method for the diagnosis of pulmonary tuberculosis, with low complication rates. The combination of TBB and BAL increases the sensitivity of the method and facilitates the differential diagnosis with other diseases.

PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in Smear-Negative patients

Abstract Background Smear-negative pulmonary tuberculosis (SNPTB) accounts for 30% of Pulmonary Tuberculosis (PTB) cases reported annually in developing nations. Polymerase chain reaction (PCR) may provide an alternative for the rapid detection of Mycobacterium tuberculosis (MTB); however little data are available regarding the clinical utility of PCR in SNPTB, in a setting with a high burden of TB/HIV co-infection. Methods To evaluate the performance of the PCR dot-blot in parallel with pretest probability (Clinical Suspicion) in patients suspected of having SNPTB, a prospective study of 213 individuals with clinical and radiological suspicion of SNPTB was carried out from May 2003 to May 2004, in a TB/HIV reference hospital. Respiratory specialists estimated the pretest probability of active disease into high, intermediate, low categories. Expectorated sputum was examined by direct microscopy (Ziehl-Neelsen staining), culture (Lowenstein Jensen) and PCR dot-blot. Gold standard was based on culture positivity combined with the clinical definition of PTB. Results In smear-negative and HIV subjects, active PTB was diagnosed in 28.4% (43/151) and 42.2% (19/45), respectively. In the high, intermediate and low pretest probability categories active PTB was diagnosed in 67.4% (31/46), 24% (6/25), 7.5% (6/80), respectively. PCR had sensitivity of 65% (CI 95%: 50%–78%) and specificity of 83% (CI 95%: 75%–89%). There was no difference in the sensitivity of PCR in relation to HIV status. PCR sensitivity and specificity among non-previously TB treated and those treated in the past were, respectively: 69%, 43%, 85% and 80%. The high pretest probability, when used as a diagnostic test, had sensitivity of 72% (CI 95%:57%–84%) and specificity of 86% (CI 95%:78%–92%). Using the PCR dot-blot in parallel with high pretest probability as a diagnostic test, sensitivity, specificity, positive and negative predictive values were: 90%, 71%, 75%, and 88%, respectively. Among non-previously TB treated and HIV subjects, this approach had sensitivity, specificity, positive and negative predictive values of 91%, 79%, 81%, 90%, and 90%, 65%, 72%, 88%, respectively. Conclusion PCR dot-blot associated with a high clinical suspicion may provide an important contribution to the diagnosis of SNPTB mainly in patients that have not been previously treated attended at a TB/HIV reference hospital.

Comparison of two laboratory-developed PCR methods for the diagnosis of Pulmonary Tuberculosis in Brazilian patients with and without HIV infection

Abstract Background Direct smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of pulmonary tuberculosis (PTB) is cheap and easy to use, but its low sensitivity is a major drawback, particularly in HIV seropositive patients. As such, new tools for laboratory diagnosis are urgently needed to improve the case detection rate, especially in regions with a high prevalence of TB and HIV. Objective To evaluate the performance of two in house PCR (Polymerase Chain Reaction): PCR dot-blot methodology (PCR dot-blot) and PCR agarose gel electrophoresis (PCR-AG) for the diagnosis of Pulmonary Tuberculosis (PTB) in HIV seropositive and HIV seronegative patients. Methods A prospective study was conducted (from May 2003 to May 2004) in a TB/HIV reference hospital. Sputum specimens from 277 PTB suspects were tested by Acid Fast Bacilli (AFB) smear, Culture and in house PCR assays (PCR dot-blot and PCR-AG) and their performances evaluated. Positive cultures combined with the definition of clinical pulmonary TB were employed as the gold standard. Results The overall prevalence of PTB was 46% (128/277); in HIV+, prevalence was 54.0% (40/74). The sensitivity and specificity of PCR dot-blot were 74% (CI 95%; 66.1%-81.2%) and 85% (CI 95%; 78.8%-90.3%); and of PCR-AG were 43% (CI 95%; 34.5%-51.6%) and 76% (CI 95%; 69.2%-82.8%), respectively. For HIV seropositive and HIV seronegative samples, sensitivities of PCR dot-blot (72% vs 75%; p = 0.46) and PCR-AG (42% vs 43%; p = 0.54) were similar. Among HIV seronegative patients and PTB suspects, ROC analysis presented the following values for the AFB smear (0.837), Culture (0.926), PCR dot-blot (0.801) and PCR-AG (0.599). In HIV seropositive patients, these area values were (0.713), (0.900), (0.789) and (0.595), respectively. Conclusion Results of this study demonstrate that the in house PCR dot blot may be an improvement for ruling out PTB diagnosis in PTB suspects assisted at hospitals with a high prevalence of TB/HIV.

Epidemiological aspects of tuberculosis in children and adolescents in Rio de Janeiro

Objective: To describe the epidemiological aspects of childhood tuberculosis (TB) in a Brazilian reference hospital. Methods: This was a retrospective study (1999-2008) of 473 subjects (0-14 year olds) with confirmed TB, or with clinical improvement by the fourth month of treatment under the unit's care, including the review of medical records, monitoring reports and notifications by the TB unit. Results: Among 473 TB cases included in the study, positive tuberculin skin test was observed in 52%, history of contact with a patient with pulmonary tuberculosis in 66%, mostly intra-household, and with the father/stepfather most commonly involved; and disseminated TB in 22%. The result of HIV testing was obtained in 265 (56%) cases, being positive in 45 (17%). The diagnosis of TB was confirmed in 31% of cases, most frequently in children older than 5 years, with negative tuberculin skin test, and in disseminated forms. Of the 65 cultures positive for TB performed in the study, drug sensitivity testing to anti-TB drugs was done in 30 (46%) clinical samples, among which 10 (33%) were resistant to one or more anti-TB drugs, and 2 (0.8%) were multi-drug-resistant. Among patients with confirmed pulmonary TB, 31% did not meet the criteria for starting anti-TB treatment according to the scores of the Ministry of Health (<= 25 points). Conclusion: The high proportion of drug-resistant TB and co-infection with HIV identified in this study highlight the necessity to carry out additional studies in order to evaluate the impact of TB control activities on childhood TB.

Differentiating between tuberculosis-related and lymphoma-related lymphocytic pleural effusions by measuring clinical and laboratory variables: Is it possible?

Objective: To describe clinical and laboratory characteristics in patients with tuberculosis-related or lymphoma-related lymphocytic pleural effusions, in order to identify the variables that might contribute to differentiating between these diseases. Methods: This was a retrospective study involving 159 adult HIV-negative patients with tuberculosis-related or lymphoma-related lymphocytic effusions (130 and 29 patients, respectively), treated between October of 2008 and March of 2010 at the Pleural Diseases Outpatient Clinic of the University of Sao Paulo School of Medicine Hospital das Clinicas Heart Institute, in the city of Sao Paulo, Brazil. Results: Mean age and the mean duration of symptoms were lower in the tuberculosis group than in the lymphoma group. The levels of proteins, albumin, cholesterol, amylase, and adenosine deaminase (ADA) in pleural fluid, as well as the serum levels of proteins, albumin, and amylase, were higher in the tuberculosis group, whereas serum cholesterol and triglycerides were higher in the lymphoma group. Pleural fluid leukocyte and lymphocyte counts were higher in the tuberculosis group. Of the tuberculosis group patients, none showed malignant cells; however, 4 showed atypical lymphocytes. Among the lymphoma group patients, cytology for neoplastic cells was positive, suspicious, and negative in 51.8%, 24.1%, and 24.1%, respectively. Immunophenotyping of pleural fluid was conclusive in most of the lymphoma patients. Conclusions: Our results demonstrate clinical and laboratory similarities among the patients with tuberculosis or lymphoma. Although protein and ADA levels in pleural fluid tended to be higher in the tuberculosis group than in the lymphoma group, even these variables showed an overlap. However, none of the tuberculosis group patients had pleural fluid ADA levels below the 40-U/L cut-off point.

Knowledge as a factor in vulnerability to tuberculosis among nursing students and professionals

The objective of this study was to identify vulnerability to tuberculosis (TB) related to knowledge about the disease among 76 nursing students and professionals. A quantitative descriptive study was conducted using a closed questionnaire for the collection of data regarding transmission, preventive and biosafety measures, diagnosis, and prejudice regarding the disease. The SAS software version 9.1.3 was used for data analysis, with the level of significance set at 5% (p < 0.05). Nursing students and professionals showed a vulnerability to TB related to knowledge about transmission, preventive and biosafety measures, and diagnosis of the disease. With respect to transmission, vulnerability was higher among nursing professionals. The results indicate the need for investment by healthcare institutions surrounding this topic in view of the important role of nursing in the establishment of strategies for prevention and control of the disease.

Family health team knowledge concerning the health needs of people with tuberculosis

The purposes of the study were to get to know conceptions on tuberculosis and health needs and to describe the care provided to people with tuberculosis, according to health professionals' perspective. Qualitative study developed at family health units in Capao Redondo, Sao Paulo. The data were collected through open interviews in January 2010 and submitted to discourse analysis, resulting in three categories: meanings attributed to tuberculosis and health needs and care characteristics. The conceptions regarding the disease are supported by the multi-causal theory of the health-disease process. The care is characterized by interventions that go beyond the biological dimension. The precarious living conditions define the needs of most people with tuberculosis, and can be more important to the ill than the very diagnosis of the disease, influencing treatment adherence, and should gain relevance in care.

TUBERCULOSIS AMONG HIV-1-INFECTED SUBJECTS IN A TERTIARY OUT-PATIENT SERVICE IN SÃO PAULO CITY, BRAZIL

TB is currently considered to be the most important infectious disease among HIV-1-infected subjects in developing countries, such as Brazil. A retrospective analysis of TB cases was performed, occurring from January 1995 to December 2010 in our cohort of 599 HIV positive patients. The primary outcome was the occurrence of active TB. Forty-one TB cases were diagnosed over this period of 16 years, among 599 HIV positive patients in an open cohort setting in the city of Sao Paulo, Brazil. All-time lowest mean CD4 T cell count at the time of TB diagnosis was 146 and 186 cells/mm3, respectively. The mean HIV viral load was 5.19 log10 copies/mL, and 59% of the patients were on HAART. TB incidence was 1.47 per 100 person-years, for a total follow-up time of 2775 person-years. The probability of surviving up to 10 years after diagnosis was 75% for TB patients as opposed to 96% for patients with other, non-TB opportunistic diseases (p = 0.03). TB can be considered a public health problem among people living with HIV in Brazil despite of the widespread use of antiretrovirals for the treatment of HIV infection/AIDS.