Epidemiology of tuberculosis among healthcare personnel in New York City.

BACKGROUND: We have updated the epidemiology of tuberculosis (TB) among healthcare personnel (HCP) in New York City (NYC), USA, during a period of declining TB burden.METHODS: Using routinely collected Health Department data for NYC TB cases from 2001 to 2014, we conducted a retrospective descriptive analysis. P values were calculated using Pearson's χ² or Fisher's exact test for categorical data; Wilcoxon rank-sum test was used to compare medians. We used the Cochran-Armitage test for trend and linear regression for trend analyses.RESULTS: HCP accounted for 6% of adults with TB throughout the study period and were more likely than other adults to be female (68% vs. 37%, P ≤ 0.0001), have extrapulmonary-only disease (31% vs. 23%, P ≤ 0.0001), have an isolate with multidrug resistance (4% vs. 2%, P = 0.0211), and report a previous history of latent TB infection (LTBI) (51% vs. 23%, P ≤ 0.0001). Compared to non-US-born HCP, US-born HCP were more likely to have HIV infection (18% vs. 8%, P = 0.0011) or a genotypically clustered isolate (67% vs. 37%, P ≤ 0.0001) and less likely to report history of prior LTBI (43% vs. 54%, P = 0.0128).CONCLUSIONS: Further research is needed to explore transmission and occupational risk among HCP. New approaches are needed to optimize completion of prophylaxis for HCP with LTBI.

Mortality among tuberculosis patients in New York City.

OBJECTIVES: To quantify tuberculosis (TB) related mortality among TB patients in New York City (NYC), NY, USA, and identify risk factors associated with TB-related mortality. DESIGN: We performed a retrospective analysis of verified TB patients in NYC, 2004-2013. NYC Office of Vital Statistics death certificate data and TB surveillance data were matched. Death certificate data were used to identify TB-related deaths. Risk factors for TB-related death for US-born and non-US-born populations were evaluated using multivariable logistic regression. RESULTS: Of 8209 TB patients in NYC, 168 (2%) suffered TB-related deaths before or during anti-tuberculosis treatment. Of these, 62% occurred among non-US-born patients, and 38% occurred among US-born patients. Among the latter, TB-related death was associated with increased age (65 vs. 18-44 years, adjusted OR [aOR] 8.27, 95%CI 3.47-19.71), being culture-positive (aOR 6.79, 95%CI 2.10-21.97), and having both pulmonary and extra-pulmonary disease (aOR 5.06, 95%CI 1.91-13.40). The same factors were also significant among non-US-born patients; TB-related death was also associated with male sex (aOR 1.80, 95%CI 1.11-2.91), history of TB disease (aOR 3.16, 95%CI 1.28-7.77), alcohol use (aOR 1.85, 95%CI 1.00-3.43), homelessness (aOR 2.66 95%CI 1.15-6.19), and unknown human immunodeficiency virus status (aOR 3.91, 95%CI 2.43-6.29). CONCLUSION: Different risk factors between the US- and non-US-born populations were identified. Interventions specific to each population may be needed for reducing TB-related mortality.

Exploring genotype concordance in epidemiologically linked cases of tuberculosis in New York City.

Comparing genotype results of tuberculosis (TB) isolates from individuals diagnosed with TB can support or refute transmission; however, these conclusions are based upon the criteria used to define a genotype match. We used a genotype-match definition which allowed for variation in IS6110 restriction fragment length polymorphism (RFLP) to support transmission between epidemiologically linked persons. Contacts of individuals with infectious TB (index cases) diagnosed in New York City from 1997 to 2003 who subsequently developed TB (contact cases) from 1997 to 2007 were identified. For each contact case and index case (case-pair), isolate genotypes (spoligotype and RFLP results) were evaluated. Isolates from case-pairs were classified as exact or non-exact genotype match. Genotypes from non-exact match case-pairs were reviewed at the genotyping laboratory to determine if the isolates met the near-genotype-match criteria (exactly matching spoligotype and similar RFLP banding patterns). Of 118 case-pairs identified, isolates from 83 (70%) had exactly matching genotypes and 14 (12%) had nearly matching genotypes (supporting transmission), while the remaining 21 (18%) case-pairs had discordant genotypes (refuting transmission). Using identical genotype-match criteria for isolates from case-pairs epidemiologically linked through contact investigation may lead to underestimation of transmission. TB programmes should consider the value of expanding genotype-match criteria to more accurately assess transmission between such cases.

Health care provider perspectives on tuberculosis care for foreign-born populations in New York City.

BACKGROUND: Tuberculosis (TB) in foreign-born patients is a key determinant of TB epidemiology in low-burden settings. In New York City (NYC), foreign-born TB populations are heterogeneous and face diverse challenges in accessing care. OBJECTIVE: To characterize barriers and facilitators to health care services and identify potential mechanisms to improve TB care for foreign-born patients in NYC. DESIGN: Semi-structured interviews with health care providers identified through the NYC TB registry and snowball sampling. Transcripts were analyzed using a modified grounded theory approach. RESULTS: Fourteen providers from private practice (21%), community clinic (36%), and hospitals (43%) were interviewed. Barriers clustered into thematic areas: interrelated social and economic issues that impact TB care and treatment (documentation status, poverty, mental/behavioral health issues), challenges of fragmented health system (care continuity, costs), latent tuberculous infection, and relative lack of resources and significant barriers for clinic and private practice providers. Health care providers' deep commitment to foreign-born TB patients was evidenced by their attitudes and actions. CONCLUSION: Improving access to TB care for foreign-born patients in NYC requires strategies that address specific social, economic and structural barriers. Improving linkages between private providers and public health initiatives is a key challenge. Health care providers' commitment to foreign-born communities is a significant resource.

Errors in isolation of patients with infectious tuberculosis at a public teaching hospital in New York.

BACKGROUND: Studies report variability in the rates and causes of isolation errors among in-patients with active tuberculosis (TB). We reviewed our experience with delays or premature discontinuation of airborne infection isolation (AII). METHODS: Medical records of patients admitted to the Bellevue Hospital Center, New York City Health & Hospitals, New York, NY, USA, between January 2006 and July 2012 with a positive respiratory culture for Mycobacterium tuberculosis were reviewed. Patients who were out of AII despite being infectious were identified, as the episodes had prompted a contact investigation. RESULTS: Of 246 admissions with positive respiratory cultures, 35 AII errors were identified among 27 patients. Most patients had signs or symptoms of TB on admission. Only four patients had positive sputum smears. In 16 (46%) episodes, the patients had never been isolated, 11 (31%) had delayed isolation, and 8 (23%) were prematurely taken off AII. The most common reasons for patients being off AII while infectious were an incorrect alternative diagnosis (15/35, 43%) or a dual diagnosis (9/35, 26%). CONCLUSIONS: Particularly in smear-negative cases, AII errors due to TB may occur when providers conclude that another diagnosis explains their findings. In many cases, that diagnosis is correct, but TB is also present. This error rate might be a useful quality indicator.

Characteristics and TB treatment outcomes in TB patients with viral hepatitis, New York City, 2000-2010.

Literature surrounding the burden of and factors associated with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in persons with tuberculosis (TB) disease remains limited and focused on populations outside the USA. Cross-matched New York City (NYC) TB and viral hepatitis surveillance data were used to estimate the proportion of NYC adults diagnosed with TB from 2000 to 2010 with a report of viral hepatitis infection and to describe the impact of viral hepatitis infection on TB treatment completion and death. For 9512 TB patients, HCV infection was reported in 4.2% and HBV infection in 3.7%; <1% of TB patients had both HCV and HBV infection. The proportion of TB patients with HCV infection to die before TB treatment completion was larger than in TB patients without a viral hepatitis report (21% vs. 9%); this association remained when stratified by HIV status. There was no significant difference in death before treatment completion for TB patients with HBV infection compared to TB patients without a viral hepatitis report when stratified by HIV status. These findings reinforce the importance of hepatitis testing and providing additional support to TB patients with viral hepatitis infection.

Achieving international targets for tuberculosis treatment success among HIV-positive patients in New York City.

OBJECTIVE: To review outcomes of human immunodeficiency virus (HIV) positive tuberculosis (TB) patients in New York City (NYC) to determine if the World Health Organization treatment success target of 85% was met in a setting with ready access to treatment for HIV and TB. DESIGN: Retrospective review of new TB patients diagnosed from 1995 to 2004, excluding patients with rifampin (RMP) resistance. RESULTS: Of 9198 eligible TB patients, 83% had achieved treatment success, 8% died during treatment, 4% failed, 3% defaulted and 2% were transferred from NYC. Among 6374 HIV-negative individuals, treatment success was consistently over 85%; 5% died during treatment. Among 2824 HIV-positive individuals, treatment success was 72% overall and 66% in sputum acid-fast bacilli smear-positive patients. Mortality among the HIV-positive decreased from 26% in 1995 to 14% in 2004. HIV-positive patients achieved higher treatment success if 1) they received treatment by directly observed therapy (DOT) (82% vs. 74%, OR(adj) = 1.80, 95%CI 1.44-2.26), or 2) were administered rifabutin (RFB) in the regimen, a proxy for receiving antiretroviral therapy (ART) (84% vs. 78%, OR(adj) = 1.49, 95%CI 1.20-1.85). Treatment success of 85% was achieved in HIV-positive patients who received RFB and DOT. CONCLUSION: High mortality precluded achieving 85% treatment success among HIV-positive TB patients. DOT and ART remain essential for improving success among co-infected patients everywhere.

Ensuring accountability: the contribution of the cohort review method to tuberculosis control in New York City.

SETTING: In 1993, the New York City (NYC) Bureau of Tuberculosis Control developed the cohort review process as a quality assurance method to track and improve patient outcomes. METHODS: The Bureau Director reviews every tuberculosis (TB) case quarterly in a multi-disciplinary staff meeting. In 2004 we also began collecting details on issues identified at cohort review to quantify how this process directly impacts TB control efforts. RESULTS: From 1992 to 2004, NYC TB cases decreased by 72.7% and treatment success rates significantly increased by 26.7%. Implementing the cohort review was key to improving case management, thus leading to these results. For the 1039 patients in 2004, 596 issues were identified among 424 patients; 55.0% were incorrect, unclear or unknown patient information, 13.8% were treatment issues, 12.4% were case management issues and 10.6% were incomplete contact investigations. Most (76.5%) issues were addressed within 30 days of the cohort reviews. CONCLUSION: A systematic review of every TB case improves the quality of patient information, enhances patient treatment and ensures accountability at all levels of the TB control program.

Public-private collaboration for multidrug-resistant tuberculosis control in New York City.

SETTING: An urban tuberculosis control program where an enhanced multidrug-resistant tuberculosis (MDR-TB) management plan coordinated care with multiple providers. OBJECTIVE: To evaluate treatment outcomes of primary MDR-TB patients treated by multiple providers. DESIGN: Retrospective cohort study of tuberculosis patients from 1992-1997 provided that 1) their Mycobacterium tuberculosis isolates were resistant to at least isoniazid and rifampin, and 2) they had had < or = 30 days of anti-tuberculosis treatment prior to the collection of the first MDR-TB specimen. RESULTS: More than 100 facilities and providers reported 856 MDR-TB patients. Treatment completion reached 70% among non-HIV-infected and 30% among HIV-infected persons; 57.2% of the cohort died prior to treatment completion, 26.5% completed treatment, 16.0% transferred out, refused treatment or were lost to follow-up and 0.2% are still in care. Diagnosis in the later years of the study or cavitation on chest radiograph was independently associated with increased completion among HIV-infected patients. Eight of the 227 (3.5%) patients who completed treatment relapsed (relapse rate 1.01/100 person-years), two with drug-susceptible strains. CONCLUSION: A comprehensive MDR-TB control program improved the outcomes of both HIV-infected and non-infected individuals, despite management by multiple providers. Relapse was infrequent among patients who completed the recommended regimens.

Prophylactic amnioinfusion during labor complicated by meconium.

A prospective study to see the safety and efficacy of transcervical amnioinfusion in labour complicated by meconium-stained amniotic fluid (MSAF) was carried out in a teaching hospital with limited resources. Fifty patients in labour with meconium-stained amniotic fluid and fulfilling the inclusion criteria (vertex presentation, gestational age of 36 weeks or more, no medical or obstetrical complications and normal fetal heart rate at time of inclusion) were taken for the study, 25 patients received amnioinfusion. The control group received only supportive therapy. Labour outcome was compared in the 2 groups. The incidence of Caesarean section was seen to be decreased but neonatal parameters showed no significant difference in the amnioinfusion group.

Estimated spectrum of a 4-MV therapeutic beam.

We have made a comparative investigation of the estimated spectra obtained by the Laplace transform analysis of the transmitted exposure data measured in an absorption study of a 4-MV x-ray beam. Four transform pair models currently used with this method have been evaluated. It has been determined that the Archer-Wagner model provides a valid representation of the measured transmission data and yields an estimated spectrum which most closely resembles a Monte Carlo spectrum calculated for a 4-MV therapeutic x-ray beam available from a typical medical accelerator.

Evaluation of tissue-air ratios and tissue-maximum ratios with the photon energy-fluence absorption dose model.

Values of tissue-air ratio (TAR) and tissue-maximum ratio (TMR) have been calculated with the photon energy-fluence absorption dose model, at depths d greater than dn (depth of dose normalization) in a homogeneous water phantom, for Co-60 gamma-ray, and 4, 6, 10, 14, and 45 MVp x-ray beams of EQS (the side of the equivalent square) up to 20 cm. It has been found that by (i) slightly altering the formula for the depth modification factor so that it depends on the difference (d -- dn) rather than d alone; and (ii) permitting E, the effective energy of the beam, to vary with EQS for some x-ray beams, it is possible for the model to reproduce within 2.5% the measured data at depths d greater than dn, on TAR, TMR and PDD (the central axis percent depth dose), for any source to surface distance.

Semi-empirical model for depth dose distributions of megavoltage x-ray beams.

The dose distribution due to absorption of photon energy fluence in a homogeneous water phantom irradiated by megavoltage x-ray beams has been analyzed with a semiempirical model. The method generalizes an analytical formalism for the scattering component of dose within a water phantom which was developed recently for monoenergetic photon beams. Contributions to dose via Compton interaction and pair creation form the essential structure of the secondary component formula. Both the central-axis percent depth dose and off-central-axis ratios can be determined for beams of different sizes, used at any value of source to surface distance. The input data include the values of linear attenuation and energy-absorption coefficients in water at energies between 10 keV and the equivalent energy of the beam. Predicted values of the central-axis percent depth dose and the off-central-axis ratios are compared with the measured data for 2, 4, 6, 8, 10, 14, 20, 35, 45, and 70 MVp x-ray beams. For the central-axis percent depth dose, agreement is within 3% for fields of sizes between 5 X 5 and 20 X 20 cm2, and 5% for larger fields, for beams of MVp up to 20. For higher energy beams, comparison was made only for the 10 X 10 cm2 fields and the discrepancies were within 3%. For the off-central-axis ratios, agreement between the predicted and measured values is within 5% over the umbra region but worsens in the penumbra region and geometrical shadow. This formalism requires large computer storage for generating data for all realistic beams irradiating normal-size phantoms.

Physical approach to depth dose distributions in a water phantom irradiated by a teleisotope photon beam.

The physical basis of deposition of radiation dose within a homogeneous phantom irradiated by a monoenergetic photon beam has been studied in terms of photon attenuation and energy-absorption properties of the phantom material. A semi-empirical model based on the Klein-Nishina formula for Compton scattering, and the ratio of multiply scattered to singly scattered photon fluences, has been developed for the scatter dose component within a realistic phantom to determine the central-axial percent depth dose (PDD) and off-central-axis ratios (OCR). Differences between the predicted and measured values of PDD and OCR for cobalt-60 and cesium-137 beams are less than 3% for fields of equivalent-square-side less than 20 cm, and less than 5% for larger fields. Beam profiles of all field sizes can be well simulated by this model and reasonable agreement has been found between the predicted and tabulated values of scatter functions and the backsetter factor for cobalt-60 beams. This formulation involves no variable parameters, and is valid for all values of the source-to-surface distance, field length and width, and field shape. However, the algorithm developed is not suitable for routine multiple-field treatment planning because it requires large computer memory size.