Robert Pratt

Epidemiology of Extrapulmonary Tuberculosis in the United States, 1993–2006

BACKGROUND Almost one-fifth of United States tuberculosis cases are extrapulmonary; unexplained slower annual case count decreases have occurred in extrapulmonary tuberculosis (EPTB), compared with annual case count decreases in pulmonary tuberculosis (PTB) cases. We describe the epidemiology of EPTB by means of US national tuberculosis surveillance data. METHODS US tuberculosis cases reported from 1993 to 2006 were classified as either EPTB or PTB. EPTB encompassed lymphatic, pleural, bone and/or joint, genitourinary, meningeal, peritoneal, and unclassified EPTB cases. We excluded cases with concurrent extrapulmonary-pulmonary tuberculosis and cases of disseminated (miliary) tuberculosis. Demographic characteristics, drug susceptibility test results, and risk factors, including human immunodeficiency virus (HIV) status, were compared for EPTB and PTB cases. RESULTS Among 253,299 cases, 73.6% were PTB and 18.7% were EPTB, including lymphatic (40.4%), pleural (19.8%), bone and/or joint (11.3%), genitourinary (6.5%), meningeal (5.4%), peritoneal (4.9%), and unclassified EPTB (11.8%) cases. Compared with PTB, EPTB was associated with female sex (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.7-1.8) and foreign birth (OR, 1.5; CI, 1.5-1.6), almost equally associated with HIV status (OR, 1.1; CI, 1.1-1.1), and negatively associated with multidrug resistance (OR, 0.6; CI, 0.5-0.6) and several tuberculosis risk factors, especially homelessness (OR, 0.3; CI, 0.3-0.3) and excess alcohol use (OR, 0.3; CI, 0.3-0.3). Slower annual decreases in EPTB case counts, compared with annual decreases in PTB case counts, from 1993 through 2006 have caused EPTB to increase from 15.7% of tuberculosis cases in 1993 to 21.0% in 2006. CONCLUSIONS EPTB epidemiology and risk factors differ from those of PTB, and the proportion of EPTB has increased from 1993 through 2006. Further study is needed to identify causes of the proportional increase in EPTB.

Extensively Drug-Resistant Tuberculosis in the United States, 1993-2007

CONTEXT Worldwide emergence of extensively drug-resistant tuberculosis (XDR-TB) has raised global public health concern, given the limited therapy options and high mortality. OBJECTIVES To describe the epidemiology of XDR-TB in the United States and to identify unique characteristics of XDR-TB cases compared with multidrug-resistant TB (MDR-TB) and drug-susceptible TB cases. DESIGN, SETTING, AND PATIENTS Descriptive analysis of US TB cases reported from 1993 to 2007. Extensively drug-resistant TB was defined as resistance to isoniazid, a rifamycin, a fluoroquinolone, and at least 1 of amikacin, kanamycin, or capreomycin based on drug susceptibility test results from initial and follow-up specimens. MAIN OUTCOME MEASURES Extensively drug-resistant TB case counts and trends, risk factors for XDR-TB, and overall survival. RESULTS A total of 83 cases of XDR-TB were reported in the United States from 1993 to 2007. The number of XDR-TB cases declined from 18 (0.07% of 25 107 TB cases) in 1993 to 2 (0.02% of 13 293 TB cases) in 2007, reported to date. Among those with known human immunodeficiency virus (HIV) test results, 31 (53%) were HIV-positive. Compared with MDR-TB cases, XDR-TB cases were more likely to have disseminated TB disease (prevalence ratio [PR], 2.06; 95% confidence interval [CI], 1.19-3.58), less likely to convert to a negative sputum culture (PR, 0.55; 95% CI, 0.33-0.94), and had a prolonged infectious period (median time to culture conversion, 183 days vs 93 days for MDR-TB; P < .001). Twenty-six XDR-TB cases (35%) died during treatment, of whom 21 (81%) were known to be HIV-infected. Mortality was higher among XDR-TB cases than among MDR-TB cases (PR, 1.82; 95% CI, 1.10-3.02) and drug-susceptible TB cases (PR, 6.10; 95% CI, 3.65-10.20). CONCLUSION Although the number of US XDR-TB cases has declined since 1993, coinciding with improved TB and HIV/AIDS control, cases continue to be reported each year.

Tuberculosis in Older Adults in the United States, 1993–2008

OBJECTIVES: To describe older adults with tuberculosis (TB) and compare demographic, diagnostic, and disease characteristics and treatment outcomes between older and younger adults with TB.

Tuberculosis in South Asians Living in the United States, 1993-2004

BACKGROUND Patients with tuberculosis (TB) in the United States are often described in 2 broad categories, US-born and foreign-born, which may mask differences among different immigrant groups. We determined characteristics of patients born in South Asia and diagnosed as having TB in the United States. METHODS All 224,101 TB cases reported to the US National Tuberculosis Surveillance System from the 50 states and the District of Columbia from 1993 to 2004 were included. We used descriptive analysis and logistic regression to explore differences among patients born in South Asia, other foreign-born, and US-born TB patients. RESULTS Half of the South Asian TB patients (50.5%) in our study were in the 25- to 44-year-old age group, compared with 40.1% of other foreign-born TB patients and 31.8% of US-born TB patients. Compared with other foreign-born TB patients, South Asians were more likely to have extrapulmonary disease (odds ratio [OR], 1.7), more likely to be uninfected with human immunodeficiency virus (HIV) (OR, 5.8) but also more likely not to be offered HIV testing (OR, 9.4) or not to accept an HIV test if offered (OR, 11.8), and more likely not to be homeless (OR, 2.9) or not to use drugs or excess alcohol (OR, 2.7). CONCLUSIONS South Asian TB patients in the United States are younger and more commonly develop extrapulmonary TB than other foreign-born patients. New TB control strategies that target younger patients and that encourage HIV testing and inform physicians about high extrapulmonary TB in the absence of common risk factors in South Asians are needed.

Tuberculosis among healthcare workers, United States, 1995-2007.

OBJECTIVE We examined surveillance data to describe the epidemiology of tuberculosis (TB) among healthcare workers (HCWs) in the United States during the period 1995-2007. DESIGN Cross-sectional descriptive analysis of existing surveillance data. SETTING AND PARTICIPANTS TB cases reported to the Centers for Disease Control and Prevention from the 50 states and the District of Columbia from 1995 through 2007. RESULTS Of the 200,744 reported TB cases in persons 18 years of age or older, 6,049 (3%) occurred in individuals who were classified as HCWs. HCWs with TB were more likely than other adults with TB to be women (unadjusted odds ratio [95% confidence interval], 4.1 [3.8-4.3]), be foreign born (1.3 [1.3-1.4]), have extrapulmonary TB (1.6 [1.5-1.7]), and complete TB treatment (2.5 [2.3-2.8]). CONCLUSIONS Healthcare institutions may benefit from intensifying TB screening of HCWs upon hire, especially persons from countries with a high incidence of TB, and encouraging treatment for latent TB infection among HCWs to prevent progression to TB disease.

Human Tuberculosis Caused by Mycobacterium bovis in the United States, 2006-2013.

BACKGROUND Using genotyping techniques that have differentiated Mycobacterium bovis from Mycobacterium tuberculosis since 2005, we review the epidemiology of human tuberculosis caused by M. bovis in the United States and validate previous findings nationally. METHODS All tuberculosis cases with a genotyped M. tuberculosis complex isolate reported during 2006-2013 in the United States were eligible for analysis. We used binomial regression to identify characteristics independently associated with M. bovis disease using adjusted prevalence ratios (aPRs) and corresponding 95% confidence intervals (CIs). RESULTS During 2006-2013, the annual percentages of tuberculosis cases attributable to M. bovis remained consistent nationally (range, 1.3%-1.6%) among all tuberculosis cases (N = 59 273). Compared with adults 25-44 years of age, infants aged 0-4 years (aPR, 1.9 [95% CI, 1.4-2.8]) and children aged 5-14 years (aPR, 4.0 [95% CI, 3.1-5.3]) had higher prevalences of M. bovis disease. Patients who were foreign-born (aPR, 1.4 [95% CI, 1.2-1.7]), Hispanic (aPR, 3.9 [95% CI, 3.0-5.0]), female (aPR, 1.4 [95% CI, 1.3-1.6]), and resided in US-Mexico border counties (aPR, 2.0 [95% CI, 1.7-2.4]) also had higher M. bovis prevalences. Exclusively extrapulmonary disease (aPR, 3.7 [95% CI, 3.3-4.2]) or disease that was both pulmonary and extrapulmonary (aPR, 2.4 [95% CI, 2.1-2.9]) were associated with a higher prevalence of M. bovis disease. CONCLUSIONS Children, foreign-born persons, Hispanics, and females are disproportionately affected by M. bovis, which was independently associated with extrapulmonary disease. Targeted prevention efforts aimed at Hispanic mothers and caregivers are warranted.

Mind the gap: TB trends in the USA and the UK, 2000–2011

Background TB remains a major public health concern, even in low-incidence countries like the USA and the UK. Over the last two decades, cases of TB reported in the USA have declined, while they have increased substantially in the UK. We examined factors associated with this divergence in TB trends between the two countries. Methods We analysed all cases of TB reported to the US and UK national TB surveillance systems from 1 January 2000 through 31 December 2011. Negative binominal regression was used to assess potential demographic, clinical and risk factor variables associated with differences in observed trends. Findings A total of 259 609 cases were reported. From 2000 to 2011, annual TB incidence rates declined from 5.8 to 3.4 cases per 100 000 in the USA, whereas in the UK, TB incidence increased from 11.4 to 14.4 cases per 100 000. The majority of cases in both the USA (56%) and the UK (64%) were among foreign-born persons. The number of foreign-born cases reported in the USA declined by 15% (7731 in 2000 to 6564 in 2011) while native-born cases fell by 54% (8442 in 2000 to 3883 in 2011). In contrast, the number of foreign-born cases reported in the UK increased by 80% (3380 in 2000 to 6088 in 2011), while the number of native-born cases remained largely unchanged (2158 in 2000 to 2137 in 2011). In an adjusted negative binomial regression model, significant differences in trend were associated with sex, age, race/ethnicity, site of disease, HIV status and previous history of TB (p<0.01). Among the foreign-born, significant differences in trend were also associated with time since UK or US entry (p<0.01). Interpretation To achieve TB elimination in the UK, a re-evaluation of current TB control policies and practices with a focus on foreign-born are needed. In the USA, maintaining and strengthening control practices are necessary to sustain the progress made over the last 20 years.

Estimating tuberculosis cases and their economic costs averted in the United States over the past two decades

BACKGROUND Following a concerted public health response to the resurgence of tuberculosis (TB) in the United States in the late 1980s, annual TB incidence decreased substantially. However, no estimates exist of the number and cost savings of TB cases averted. METHODS TB cases averted in the United States during 1995-2014 were estimated: Scenario 1 used a static 1992 case rate; Scenario 2 applied the 1992 rate to foreign-born cases, and a pre-resurgence 5.1% annual decline to US-born cases; and a statistical model assessed human immunodeficiency virus and TB program indices. We applied the cost of illness to estimate the societal benefits (costs averted) in 2014 dollars. RESULTS During 1992-2014, 368 184 incident TB cases were reported, and cases decreased by two thirds during that period. In the scenarios and statistical model, TB cases averted during 1995-2014 ranged from approximately 145 000 to 319 000. The societal benefits of averted TB cases ranged from US

Tuberculosis Among Persons Born in the Philippines and Living in the United States, 2000–2007

3.1 to US

Epidemiology of pediatric multidrug-resistant tuberculosis in the United States, 1993–2014

6.7 billion, excluding deaths, and from US