Racial and Ethnic Disparities in Tuberculosis Incidence, Arkansas, USA, 2010-2021.

We conducted an epidemiologic assessment of disease distribution by race/ethnicity to identify subpopulation-specific drivers of tuberculosis (TB). We used detailed racial/ethnic categorizations for the 932 TB cases diagnosed in Arkansas, USA, during 2010-2021. After adjusting for age and sex, racial/ethnic disparities persisted; the Native Hawaiian/Pacific Islander (NHPI) group had the highest risk for TB (risk ratio 173.6, 95% CI 140.6-214.2) compared with the non-Hispanic White group, followed by Asian, Hispanic, and non-Hispanic Black. Notable racial/ethnic disparities existed across all age groups; NHPI persons 0-14 years of age were at a particularly increased risk for TB (risk ratio 888, 95% CI 403-1,962). The risks for sputum smear-positive pulmonary TB and extrapulmonary TB were both significantly higher for racial/ethnic minority groups. Our findings suggest that TB control in Arkansas can benefit from a targeted focus on subpopulations at increased risk for TB.

Disease phenotypic and geospatial features vary across genetic lineages for Tuberculosis within Arkansas, 2010-2020.

Tuberculosis (TB) elimination in the United States remains elusive, and community-specific, localized intervention strategies may be necessary to meet elimination goals. A better understanding of the genotypic diversity of Mtb, the population subgroups affected by different TB strains, and differences in disease presentation associated with these strains can aid in identifying risk groups and designing tailored interventions. We analyze TB incidence and genotype data from all Arkansas counties over an 11-year time span from 2010 through 2020. We use statistical methods and geographic information systems (GIS) to identify demographic and disease phenotypic characteristics that are associated with different Mtb genetic lineages in the study area. We found the following variables to be significantly associated with genetic lineage (p<0.05): patient county, patient birth country, patient ethnicity, race, IGRA result, disease site, chest X-ray result, whether or not a case was identified as part of a cluster, patient age, occupation risk, and date arrived in the US. Different Mtb lineages affect different subpopulations in Arkansas. Lineage 4 (EuroAmerican) and Lineage 2 (East Asian) are most prevalent, although the spatial distributions differ substantially, and lineage 2 (East Asian) is more frequently associated with case clusters. The Marshallese remain a particularly high-risk group for TB in Arkansas.

Crop burning and the prevalence of asthma and COPD emergency department treatments in a rural Arkansas county.

OBJECTIVE: To evaluate the impact of crop burning on the prevalence of asthma and COPD emergency department (ED) treatments in a rural Arkansas county. METHODS: Administrative datasets listing ED treatments for asthma and COPD obtained from the Arkansas Hospital Discharge Dataset System for the calendar years 2014-2016 were used in this semi-ecological study. Primary diagnosis codes (ICD-9: 490-496 and ICD-10: J40-J47) were used to identify patients who were diagnosed with asthma and COPD. Patients with a reported county of residence in Craighead County were determined as case county residents and those in Sebastian County were control county residents. Month of visit was used to determine seasonal variation. PM 2.5 air quality data were obtained from the EPA AQS Data Mart. RESULTS: Between 2014 through 2016, there were a combined total of 2,536 ED treatments due to asthma and 8,530 due to COPD in Craighead and Sebastian counties. The odds of being treated in the ED during the fall months for asthma and COPD are associated with a 20.9% increase and 16.9% increase respectively in Craighead County as compared to Sebastian Country after adjusting for potential confounders (p = 0.04, p = 0.003). PM 2.5 concentrations were higher in Craighead County than Sebastian County during the fall season (p = 0.005). CONCLUSION: Fall ED treatments for asthma and COPD were higher in Craighead County, Arkansas compared to Sebastian County, Arkansas for the years 2014-2016. PM 2.5 levels were also higher in Craighead County in the fall during these years. These differences may be attributable to crop burning.​.

Tuberculosis and leprosy infections in the Marshallese population of Arkansas, USA.

The cross-immunity between tuberculosis and leprosy is unknown. The aim of this pilot study was to evaluate the occurrence of Mycobacterium tuberculosis and M. leprae infection in Marshallese adult volunteers in Springdale, Arkansas, U.S.A., a population that experiences high rates of leprosy and tuberculosis. We used immunodiagnostic testing for tuberculosis and leprosy infection and found significant prevalence of latent tuberculosis infection (19.0%), and asymptomatic Mycobacterium leprae infection (22.2%). We found a negative association between presence of antibodies to Mycobacterium leprae and a positive interferon-γ release assay for Mycobacterium tuberculosis infection, prevalence odds ratio = 0.1 (95% CI = 0.0, 0.9). Although these findings require confirmation on a larger scale, they are supportive of the existence of cross-immunity.

Neighborhood and Acute Myocardial Infarction Mortality as Related to the Driving Time to Percutaneous Coronary Intervention-Capable Hospital.

BACKGROUND: Driving time to a percutaneous coronary intervention (PCI)-capable hospital is important in timely treatment of acute myocardial infarction (AMI). Our objective was to determine whether driving time from one's residence to a PCI-capable hospital contributes to AMI deaths. We conducted a cross-sectional study of age- and sex-adjusted mortality in census block groups to evaluate this question. METHODS AND RESULTS: We studied all (14 027) AMI deaths that occurred during 2008-2012 in Arkansas to assess the relationship between driving time from the population center of a block group (neighborhood) to the nearest PCI-capable hospital. We estimated standardized mortality ratios in block groups that were adjusted for education (population over 25 years of age who did not graduate from high school), poverty (population living below federal poverty level), population density (population per square mile), mobility (population residing at the same address as 1 year ago), black (population that is black), rurality (rural households), geodesic distance, and driving time. The median geodesic distance and driving time were 12.8 miles (interquartile range 3.6-30.1) and 28.3 minutes (interquartile range 9.6-58.7), respectively. Risks in neighborhoods with long driving times (90th percentile) were 26% greater than risks in neighborhoods with short driving times (10th percentile), even after adjusting for education, poverty, population density, rurality, and black race (P<0.0001). CONCLUSIONS: AMI mortality increases with increasing driving time to the nearest PCI-capable hospital. Improving the healthcare system by reducing time to arrive at a PCI-capable hospital could reduce AMI deaths.

Effectiveness of contact investigations for tuberculosis control in Arkansas.

Comprehensive assessment of the effectiveness of contact investigations for tuberculosis (TB) control is still lacking. In this study, we use a computational model, calibrated against notification data from Arkansas during the period 2001-2011, that reproduces independent data on key features of TB transmission and epidemiology. The model estimates that the Arkansas contact investigations program has avoided 18.6% (12.1-25.9%) of TB cases and 23.7% (16.4-30.6%) of TB deaths that would have occurred during 2001-2014 if passive diagnosis alone were implemented. If contacts of sputum smear-negative cases had not been included in the program, the percentage reduction would have been remarkably lower. In addition, we predict that achieving national targets for performance indicators of contact investigation programs has strong potential to further reduce TB transmission and burden. However, contact investigations are expected to have limited effectiveness on avoiding reactivation cases of latent infections over the next 60 years.

Tuberculosis reinfection in a pregnant cystic fibrosis patient.

Cystic Fibrosis (CF) is a multisystem disease predominantly affecting the airways and predisposing patients to recurrent infections with various multidrug resistant organisms. Mycobacterium tuberculosis (MTB) infection is rarely seen, but considered a potential pathogen in CF patients. We report a 26 year old pregnant CF patient on Ivacaftor who was admitted with symptoms suggestive of tuberculosis. Three years prior to the current admission, she had completed four drug anti- MTB therapy for pulmonary tuberculosis and was considered cured as her sputum cultures after six months of treatment were negative. Genotype analysis revealed the current MTB strain to be different from the strain causing the previous infection. After receiving first line anti-tuberculous regimen for nine months, the patient's condition markedly improved culminating in an uneventful pregnancy and delivery. To our knowledge, this is the only reported case of reinfection tuberculosis in a CF patient.

The road to tuberculosis (Mycobacterium tuberculosis) elimination in Arkansas; a re-examination of risk groups.

OBJECTIVES: This study was conducted to generate knowledge useful for developing public health interventions for more effective tuberculosis control in Arkansas. METHODS: The study population included 429 culture-confirmed reported cases (January 1, 2004-December 31, 2010). Mycobacterium tuberculosis genotyping data were used to identify cases likely due to recent transmission (clustered) versus reactivation (non-clustered). Poisson regression models estimated average decline rate in incidence over time and assessed the significance of differences between subpopulations. A multinomial logistic model examined differences between clustered and non-clustered incidence. RESULTS: A significant average annual percent decline was found for the overall incidence of culture-confirmed (9%; 95% CI: 5.5%, 16.9%), clustered (6%; 95% CI: 0.5%, 11.6%), and non-clustered tuberculosis cases (12%; 95% CI: 7.6%, 15.9%). However, declines varied among demographic groups. Significant declines in clustered incidence were only observed in males, non-Hispanic blacks, 65 years and older, and the rural population. CONCLUSIONS: These findings suggest that the Arkansas tuberculosis control program must target both traditional and non-traditional risk groups for successful tuberculosis elimination. The present study also demonstrates that a thorough analysis of TB trends in different population subgroups of a given geographic region or state can lead to the identification of non-traditional risk factors for TB transmission. Similar studies in other low incidence populations would provide beneficial data for how to control and eventually eliminate TB in the U.S.

The neighborhood where you live is a risk factor for stroke.

BACKGROUND: The excess stroke mortality in the southeastern states of the United States (stroke-belt states) is well known; however, the factors associated with this pattern have not been fully elucidated. We measured the contribution of several demographic factors by analyzing stroke mortality data (2005-2009) at the census block group (BG) level in the state of Arkansas. METHODS AND RESULTS: Census BGs were used as proxies for neighborhoods. BGs were stratified using 5 census measures: poverty (percent of population below federal poverty level), population density (population per square mile), education (percent of population aged >25 years who did not graduate from high school), population mobility (percent of population who resided at the same address 1 year ago), and the percent of non-Hispanic blacks (percent of population that is black). Generalized additive models were used to estimate the variation in stroke mortality among BGs and to assess the impact of different demographic variables. From 2005 to 2009, there were 8930 stroke deaths in Arkansas. There was considerable variation in the relative risk even between adjacent BGs within a single county. The geographically weighted regression analyses indicated that 4.5% to 9% of deviance in stroke mortality among BGs could be explained by poverty, education, population density, and population mobility. Race/ethnicity (non-Hispanic blacks) explains <2% of the deviance in stroke mortality among BGs. CONCLUSIONS: Our study shows that primordial risk factors such as poverty and education drive disparities in stroke mortality among neighborhoods in Arkansas.

Identification of factors for tuberculosis transmission via an integrated multidisciplinary approach.

It was reported previously that the major fraction of the recent decrease of tuberculosis incident cases in Arkansas had been due to a decrease in the reactivated infections. Preventing transmission of Mycobacterium tuberculosis is the key to a continued decline in tuberculosis cases. In this study, we integrated epidemiological data analysis and comparative genomics to identify host and microbial factors important to tuberculosis transmission. A significantly higher proportion of cases in large clusters (containing >10 cases) were non-Hispanic black, homeless, less than 65 years old, male sex, smear-positive sputum, excessive use of alcohol, and HIV sero-positive, compared to cases in small clusters (containing 2-5 cases) diagnosed within one year. However, being non-Hispanic black and homeless within the past year were the only two host characteristics that were identified as independent risk factors for being in large clusters. This finding suggests that social behavioral factors have a more important role in transmission of tuberculosis than does the infectiousness of the source. Comparing the genomic content of one of the large cluster strains to that of a non-clustered strain from the same community identified 25 genes that differed between the two strains, potentially contributing to the observed differences in transmission.

Change in mortality from coronary heart disease and stroke in Arkansas (1979 to 2007).

Coronary heart disease (CHD)- and stroke-related mortality rates have been greater in the Southern states than in the rest of the United States. Although a sustained decrease in mortality from CHD and stroke has occurred in the United States during the past 3 decades, it is not known whether a similar decrease occurred in the Southern states. We examined CHD- and stroke-related deaths from 1979 to 2007 in Arkansas and observed a marked and steady decrease in both death rates. A concurrent increase occurred in the prevalence of obesity, hypertension, and diabetes mellitus, with a decrease in physical inactivity and poverty during this period. However, we noted a significant decrease in the per capita cigarette sales in Arkansas that closely paralleled the decrease in CHD- and stroke-related deaths. In conclusion, although the extensive use of cardioprotective drugs, as well as coronary revascularization, might have contributed to the decrease, we have provided evidence to suggest that the decrease in cigarette smoking was a very important factor in the decrease in CHD- and stroke-related mortality.

Incidence of female breast cancer in Arkansas: are we following the national trend?

The incidence of invasive female breast cancer declined 6.7% in the United States from 2002 to 2003 following a nationwide decrease in the use of hormone replacement therapy that began in 2002. We used data from the Arkansas Central Cancer Registry to look for similar changes in the incidence of female breast cancer in Arkansas. There was a 9.3% decline in the incidence of invasive female breast cancer in Arkansas in 2003, and the decline continued through 2005. The decline was significantly higher (p<0.05) among invasive cancers, particularly among women ages 50 and older and for those having an estrogen-receptor positive tumor.

Does the lipR gene of tubercle bacilli have a role in tuberculosis transmission and pathogenesis?

Mycobacterium tuberculosis lipases, a diverse class of enzymes involved in lipid metabolism, may have an important role in tuberculosis (TB) pathogenesis. We explored the association of large sequence polymorphism (LSP) in one of the M. tuberculosis lipase-encoding genes, lipR (Rv3084), with patient characteristics using a population-based sample of clinical isolates to elucidate the potential role of lipR in TB pathogenesis. LSP in lipR was found in 104 (15.6%) of 665 isolates, of which 96% belonged to principal genetic group 3. When linkage by molecular type and epidemiologic evidence were compared, molecularly clustered cases infected with a lipR LSP isolate were more often epidemiologically linked than clustered cases infected with a lipR wild-type isolate. Further epidemiologic and functional studies are necessary to determine if the association between this lipR LSP and recent transmission we identified in this population reflects a functional role of lipR in TB transmission and pathogenesis or other unidentified mechanisms.

What's driving the decline in tuberculosis in Arkansas? A molecular epidemiologic analysis of tuberculosis trends in a rural, low-incidence population, 1997 2003.

Incident cases of tuberculosis may result from a recently acquired Mycobacterium tuberculosis infection or from the reactivation of a latent infection acquired in the remote past. The authors used molecular fingerprinting data to estimate the relative contributions of recent and remotely acquired infection to the yearly incidence of tuberculosis in Arkansas, a state with a largely rural population where the incidence of tuberculosis declined from 7.9 cases per 100,000 population to 4.7 cases per 100,000 between 1997 and 2003. The authors used a time-restricted definition of clustering in addition to the standard definition in order to increase the specificity of the clustering measure for recent transmission. The greatest overall declines were seen in non-Hispanic Blacks (from 13.8 cases per 100,000 in 1997 to 6.5 cases per 100,000 in 2003) and persons aged 65 years or more (from 19.9 cases per 100,000 in 1997 to 8.5 cases per 100,000 in 2003). In both groups, the incidence of nonclustered cases declined more dramatically than the incidence of clustered cases. This suggests that the decline in rates resulted primarily from declining rates of disease due to reactivation of past infections. Declines in the overall incidence of tuberculosis in a population may not necessarily result from declines in active transmission.

Association of Mycobacterium tuberculosis PE PGRS33 polymorphism with clinical and epidemiological characteristics.

There is evidence that some members of the Mycobacterium tuberculosis PE PGRS gene subfamily, including PE PGRS33, may have a specific function in M. tuberculosis persistence. The impact of naturally-occurring PE PGRS33 genetic variations on the virulence and transmissibility of clinical M. tuberculosis isolates is not known. We used PCR and DNA sequencing to identify genetic variations in the PE PGRS33 gene in comparison with the sequenced laboratory strain, H37Rv, among 649 isolates from a population-based sample. The PE PGRS33 alleles were placed into two groups, based on the effect of the sequence variations on the PE PGRS33 protein, and their associations with clinical and epidemiological characteristics were assessed using multivariate logistic regression to control for potential confounding of host-related factors. Of the 639 isolates for which sequence data were obtained, 139 (21.8%) had PE PGRS33 alleles that would result in a significant change to the PE PGRS33 protein due to large insertions/deletions or frameshift mutations. These isolates were significantly associated with clustering based on genotype and absence of cavitations in the lungs, compared to isolates having PE PGRS33 alleles that would result in no or minimal change to the PE PGRS33 protein. The association of significant changes to PE PGRS33 with clinical and epidemiological characteristics suggests that PE PGRS33 may have an important role in M. tuberculosis persistence.

Clinical relevance of Mycobacterium tuberculosis plcD gene mutations.

To identify Mycobacterium tuberculosis virulence factors, we integrated comparative genomics and epidemiologic data analysis to investigate the relationship between certain genomic insertions and deletions in the phospholipase-C gene D (plcD) with the clinical presentation of tuberculosis (TB). Four hundred ninety-six well-characterized M. tuberculosis clinical isolates were studied. Approximately 30% (147) of the isolates had an interruption of the plcD gene. Patients infected with the plcD mutant were twice as likely to have extrathoracic disease as those infected by a strain without an interruption (adjusted odds ratio, 2.19; 95% confidence interval, 1.27, 3.76). When we limited the analysis to the 275 isolates with distinct DNA fingerprint patterns, we observed the same association (adjusted odds ratio, 2.74; 95% confidence interval, 1.35, 5.56). Furthermore, the magnitude of the association appeared to differ with the type of extrathoracic TB. Our findings suggest that the plcD gene of M. tuberculosis is potentially involved in the pathogenesis of TB, and the clinical presentation of the disease may be influenced by the genetic variability of the plcD region.

Initial misdiagnosis and outcome after subarachnoid hemorrhage.

CONTEXT: Mortality and morbidity can be reduced if aneurysmal subarachnoid hemorrhage (SAH) is treated urgently. OBJECTIVE: To determine the association of initial misdiagnosis and outcome after SAH. DESIGN, SETTING, AND PARTICIPANTS: Inception cohort of 482 SAH patients admitted to a tertiary care urban hospital between August 1996 and August 2001. MAIN OUTCOME MEASURES: Misdiagnosis was defined as failure to correctly diagnose SAH at a patient's initial contact with a medical professional. Functional outcome was assessed at 3 and 12 months with the modified Rankin Scale; quality of life (QOL), with the Sickness Impact Profile. RESULTS: Fifty-six patients (12%) were initially misdiagnosed, including 42 of 221 (19%) of those with normal mental status at first contact. Migraine or tension headache (36%) was the most common incorrect diagnosis, and failure to obtain a computed tomography (CT) scan was the most common diagnostic error (73%). Neurologic complications occurred in 22 patients (39%) before they were correctly diagnosed, including 12 patients (21%) who experienced rebleeding. Normal mental status, small SAH volume, and right-sided aneurysm location were independently associated with misdiagnosis. Among patients with normal mental status at first contact, misdiagnosis was associated with worse QOL at 3 months and an increased risk of death or severe disability at 12 months. CONCLUSIONS: In this study, misdiagnosis of SAH occurred in 12% of patients and was associated with a smaller hemorrhage and normal mental status. Among individuals who initially present in good condition, misdiagnosis is associated with increased mortality and morbidity. A low threshold for CT scanning of patients with mild symptoms that are suggestive of SAH may reduce the frequency of misdiagnosis.

Identification of risk factors for extrapulmonary tuberculosis.

The proportion of extrapulmonary tuberculosis cases in the United States has increased from 16% of tuberculosis cases, in 1991, to 20%, in 2001. To determine associations between the demographic, clinical, and life style characteristics of patients with tuberculosis and the occurrence of extrapulmonary tuberculosis, a retrospective case-control study was conducted. This study included 705 patients with tuberculosis, representing 98% of the culture-proven cases of tuberculosis in Arkansas from 1 January 1996 through 31 December 2000. A comparison between 85 patients with extrapulmonary tuberculosis (case patients) and 620 patients with pulmonary tuberculosis (control patients) showed women (OR, 1.98; 95% CI, 1.25-3.13), non-Hispanic blacks (OR, 2.38; 95% CI, 1.42-3.97), and HIV-positive persons (OR, 4.93; 95% CI, 1.95-12.46) to have a significantly higher risk for extrapulmonary tuberculosis than men, non-Hispanic whites, and HIV-negative persons. This study expands the knowledge base regarding the epidemiology of extrapulmonary tuberculosis and enhances our understanding of the relative contribution of host-related factors to the pathogenesis of tuberculosis.

Transmission of Mycobacterium tuberculosis in a rural community, Arkansas, 1945-2000.

A cluster of tuberculosis cases in a rural community in Arkansas persisted from 1991 to 1999. The cluster had 13 members, 11 linked epidemiologically. Old records identified 24 additional patients for 40 linked cases during a 54-year period. Residents of this neighborhood represent a population at high risk who should be considered for tuberculin testing and treatment for latent tuberculosis infection.

Mycobacterium tuberculosis transmission between cluster members with similar fingerprint patterns.

Molecular epidemiologic studies provide evidence of transmission of Mycobacterium tuberculosis within clusters of patients whose isolates share identical IS6110-DNA fingerprint patterns. However, M. tuberculosis transmission among patients whose isolates have similar but not identical DNA fingerprint patterns (i.e., differing by a single band) has not been well documented. We used DNA fingerprinting, combined with conventional epidemiology, to show unsuspected patterns of tuberculosis transmission associated with three public bars in the same city. Among clustered TB cases, DNA fingerprinting analysis of isolates with similar and identical fingerprints helped us discover epidemiologic links missed during routine tuberculosis contact investigations.