Neighborhood poverty and the resurgence of tuberculosis in New York City, 1984-1992

OBJECTIVES

The resurgence of tuberculosis (TB) in NewYork City has been attributed to AIDS and immigration; however, the role of poverty in the epidemic is unclear. We assessed the relation between neighborhood poverty and TB at the height of the epidemic and longitudinally from 1984 through 1992.

METHODS

Census block groups were used as proxies for neighborhoods. For each neighborhood, we calculated TB and AIDS incidence in 1984 and 1992 with data from the Bureaus of Tuberculosis Control and AIDS Surveillance and obtained poverty rates from the census.

RESULTS

For 1992, 3,343 TB cases were mapped to 5,482 neighborhoods, yielding a mean incidence of 46.5 per 100,000. Neighborhood poverty was associated with TB (relative risk = 1.33; 95% confidence interval = 1.30, 1.36 per 10% increase in poverty). This association persisted after adjustment for AIDS, proportion foreign born, and race/ethnicity. Neighborhoods with declining income from 1980 to 1990 had larger increases in TB incidence than did neighborhoods with increasing income.

CONCLUSIONS

Leading up to and at the height of the TB epidemic in New York City, neighborhood poverty was strongly associated with TB incidence. Public health interventions should target impoverished areas.

Clinical efficacy of intravenous followed by oral azithromycin monotherapy in hospitalized patients with community-acquired pneumonia. The Azithromycin Intravenous Clinical Trials Group

The purpose of this study was to evaluate intravenous (i.v.) azithromycin followed by oral azithromycin as a monotherapeutic regimen for community-acquired pneumonia (CAP). Two trials of i.v. azithromycin used as initial monotherapy in hospitalized CAP patients are summarized. Clinical efficacy is reported from an open-label randomized trial of azithromycin compared to cefuroxime with or without erythromycin. Bacteriologic and clinical efficacy results are also presented from a noncomparative trial of i.v. azithromycin that was designed to give additional clinical experience with a larger number of pathogens. Azithromycin was administered to 414 patients: 202 and 212 in the comparative and noncomparative trials, respectively. The comparator regimen was used as treatment for 201 patients; 105 were treated with cefuroxime alone and 96 were given cefuroxime plus erythromycin. In the comparative trial, clinical outcome data were available for 268 evaluable patients with confirmed CAP at the 10- to 14-day visit, with 106 (77%) of the azithromycin patients cured or improved and 97 (74%) of the comparator patients cured or improved. Mean i.v. treatment duration and mean total treatment duration (i.v. and oral) for the clinically evaluable patients were significantly (P < 0.05) shorter for the azithromycin group (3.6 days for the i.v. group and 8.6 days for the i.v. and oral group) than for the evaluable patients given cefuroxime plus erythromycin (4.0 days for the i.v. group and 10.3 days for the i.v. and oral group). The present comparative study demonstrates that initial therapy with i.v. azithromycin for hospitalized patients with CAP is associated with fewer side effects and is equal in efficacy to a 1993 American Thoracic Society-suggested regimen of cefuroxime plus erythromycin when the erythromycin is deemed necessary by clinicians.

An outbreak of Legionella micdadei pneumonia in transplant patients: evaluation, molecular epidemiology, and control

PURPOSE

To describe a nosocomial outbreak of Legionella micdadei pneumonia in transplant patients and to characterize the source of the outbreak and the control measures utilized.

SUBJECTS AND METHODS

We performed retrospective Legionella micdadei serologic testing to enhance case finding in transplant patients with pneumonia that lacked a documented microbial etiology, as well as prospective environmental surveillance of water sites and testing for Legionella in clinical specimens.

RESULTS

During a 3-month period, 12 cases of Legionella micdadei pneumonia were identified either by culture or serologic testing among 38 renal and cardiac transplant patients. Legionella micdadei isolates from hot water sources were found by pulsed-field gel electrophoresis to have a DNA banding pattern that was identical to the isolates from the first 3 culture-positive cases and from 2 cases that occurred 16 months later.

CONCLUSIONS

Hospitals caring for organ transplant recipients and other immunosuppressed patients must be aware of the possibility of environmental sources of outbreaks of Legionella infection. A first-line screen with the Legionella urine antigen test will identify Legionella pneumophila serogroup 1. However, specific cultures in outbreak situations should be considered to identify other Legionella pneumophila serotypes and the nonpneumophila Legionella species.

A health information network for managing innercity tuberculosis: bridging clinical care, public health, and home care

The purpose of this study was to use a health information network and innovative technology to coordinate tuberculosis care. An innercity medical center, a local health department, and a home care nurse service in northern Manhattan were used. The organizations were linked with computer networks. An automated decision support system with a natural language processor was used to detect tuberculosis cases and report them to the health department, and to select patients for respiratory isolation. Educational materials were placed on the World Wide Web and a Web-based kiosk. Home care nurses were outfitted with wireless pen-based computers, and data were relayed to the medical center. Automated tuberculosis case reporting resulted in time savings but not improved accuracy. Automated rules resulted in significant improvements in respiratory isolation. Kiosk educational materials were well-used. Wireless computing led to better access to information for both nurses and physicians, but not to reduction of workload. The key success element was recognition of critical priorities. It is concluded that innovative technology can facilitate the coordination of clinical care, public health, and home care.

Respiratory isolation of tuberculosis patients using clinical guidelines and an automated clinical decision support system

OBJECTIVE

To evaluate a clinical guideline and an automated computer protocol for detection and respiratory isolation of tuberculosis (TB) patients.

DESIGN

An automated computer protocol was tested on a retrospective cohort of adult culture-positive TB patients admitted from 1992 to 1993 to Columbia-Presbyterian Medical Center and evaluated prospectively from July 1995 until July 1996.

SETTING

A large teaching hospital in New York City.

PATIENTS

171 adult patients admitted from 1992 to 1993 and 43 patients admitted between July 1995 and July 1996.

INTERVENTIONS

The 1990 Centers for Disease Control and Prevention guidelines for preventing transmission of TB were adapted to formulate clinical guidelines to ensure early isolation of TB patients at Columbia-Presbyterian Medical Center.

RESULTS

Implementation of a clinical respiratory isolation protocol resulted in a significant improvement in TB patient isolation rates, from 45 (51%) of 88 in 1992 to 62 (75%) of 83 in 1993 (P<.001). In testing automated protocols, the theoretical improvement would have identified an additional 27 patients not isolated by clinicians, making the overall isolation rate 134 (78%) of 171. For the prospective evaluation, 30 (70%) of 43 TB patients were isolated by clinicians adhering to the clinical protocol. Four additional patients were identified by the automated TB protocol, making the combined isolation rate 34 (79%) of 43.

CONCLUSIONS

A clinical policy to isolate TB patients and suspected human immunodeficiency virus-infected patients with cough, fever, or radiographic abnormalities improved isolation of culture-documented TB patients from 1992 to 1993. Automated computer protocols were successful in identifying additional potentially infectious patients that clinicians failed to place on respiratory isolation. Clinical and automated protocols combined resulted in better isolation rates than a clinical protocol alone.

The role of diabetes mellitus in the higher prevalence of tuberculosis among Hispanics

OBJECTIVES

This research studied the relative contribution of diabetes mellitus to the increased prevalence of tuberculosis in Hispanics.

METHODS

A case-control study was conducted involving all 5290 discharges from civilian hospitals in California during 1991 who had a diagnosis of tuberculosis, and 37,366 control subjects who had a primary discharge diagnosis of deep venous thrombosis, pulmonary embolism, or acute appendicitis. Risk of tuberculosis was estimated as the odds ratio (OR) across race/ethnicity, with adjustment for other factors.

RESULTS

Diabetes mellitus was found to be an independent risk factor for tuberculosis. The association of diabetes and tuberculosis was higher among Hispanics (adjusted OR [ORadj] = 2.95: 95% confidence interval [CI] = 2.61, 3.33) than among non-Hispanic Whites (ORadj = 1.31: 95% CI = 1.19. 1.45): among non-Hispanic Blacks, diabetes was not found to be associated with tuberculosis (ORadj = 0.93: 95% CI = 0.78, 1.09). Among Hispanics aged 25 to 54, the estimated risk of tuberculosis attributable to diabetes (25.2%) was equivalent to that attributable to HIV infection (25.5%).

CONCLUSIONS

Diabetes mellitus remains a significant risk factor for tuberculosis in the United States. The association is especially notable in middle-aged Hispanics.

Nonadherence in tuberculosis treatment: predictors and consequences in New York City

BACKGROUND

Poor adherence to antituberculosis treatment is the most important obstacle to tuberculosis control.

PURPOSE

To identify and analyze predictors and consequences of nonadherence to antituberculosis treatment.

PATIENTS AND METHODS

Retrospective study of a citywide cohort of 184 patients with tuberculosis in New York City, newly diagnosed by culture in April 1991-before the strengthening of its control program-and followed up through 1994. Follow-up information was collected through the New York City tuberculosis registry. Nonadherence was defined as treatment default for at least 2 months.

RESULTS

Eighty-eight of the 184 (48%) patients were nonadherent. Greater nonadherence was noted among blacks (unadjusted relative risk [RR] 3.0, 95% confidence interval [CI] 1.1 to 8.6, compared with whites), injection drug users (RR 1.5, 95% CI 1.1 to 2.0), homeless (RR 1.4, 95% CI 1.0 to 1.8), alcoholics (RR 1.4, 95% CI 1.0 to 1.9), and HIV-infected patients (RR 1.4, 95% CI 1.1 to 1.9); also, census-derived estimates of household income were lower among nonadherent patients (P = 0.018). In multivariate analysis, only injection drug use and homelessness predicted nonadherence, yet 46 (39%) of 117 patients who were neither homeless nor drug users were nonadherent. Nonadherent patients took longer to convert to negative culture (254 versus 64 days, P < 0.001), were more likely to acquire drug resistance (RR 5.6, 95% CI 0.7 to 44.2), required longer treatment regimens (560 versus 324 days, P < 0.0001), and were less likely to complete treatment (RR 0.5, 95% CI 0.4 to 0.7). There was no association between treatment adherence and all-cause mortality.

CONCLUSIONS

In the absence of public health intervention, half the patients defaulted treatment for 2 months or longer. Although common among the homeless and injection drug users, the problem occurred frequently and unpredictably in other patients. Nonadherence may contribute to the spread of tuberculosis and the emergence of drug resistance, and may increase the cost of treatment. These data lend support to directly observed therapy in tuberculosis.

Automated tuberculosis detection

OBJECTIVE

To measure the accuracy of automated tuberculosis case detection.

SETTING

An inner-city medical center.

INTERVENTION

An electronic medical record and a clinical event monitor with a natural language processor were used to detect tuberculosis cases according to Centers for Disease Control criteria.

MEASUREMENT

Cases identified by the automated system were compared to the local health department's tuberculosis registry, and positive predictive value and sensitivity were calculated.

RESULTS

The best automated rule was based on tuberculosis cultures; it had a sensitivity of .89 (95% CI.75-.96) and a positive predictive value of .96 (.89-.99). All other rules had a positive predictive value less than .20. A rule based on chest radiographs had a sensitivity of .41 (.26-.57) and a positive predictive value of .03 (.02-.05), and rule the represented the overall Centers for Disease Control criteria had a sensitivity of .91 (.78-.97) and a positive predictive value of .15 (.12-.18). The culture-based rule was the most useful rule for automated case reporting to the health department, and the chest radiograph-based rule was the most useful rule for improving tuberculosis respiratory isolation compliance.

CONCLUSIONS

Automated tuberculosis case detection is feasible and useful, although the predictive value of most of the clinical rules was low. The usefulness of an individual rule depends on the context in which it is used. The major challenge facing automated detection is the availability and accuracy of electronic clinical data.

Identification of suspected tuberculosis patients based on natural language processing of chest radiograph reports

Identification of eligible patients from electronically available patient data is a key difficulty in computerizing clinical practice guidelines because a large amount of the relevant data is stored as free text. We have been using MedLEE (Medical Language Extraction and Encoding System), a natural language processing system, to encode the clinical information in all chest radiograph and mammogram reports. This paper describes a retrospective study to determine if MedLEE can identify patients at risk for having tuberculosis (TB) based on their admission chest radiographs. Reports of 171 adult inpatients with culture-positive TB during 1992 and 1993 were manually coded (by a TB specialist) using seven terms suggestive of TB, and were also encoded by MedLEE. Using manual coding as the gold standard, MedLEE agreed on the classification of 152/171 (88.9%) reports--129/142 (90.8%) suspicious for TB and 23/29 (79.3%) not suspicious for TB; and 1072/1197 (89.6%) terms indicative of TB. Analysis showed that most of the discrepancies were caused by MedLEE not finding the location of the infiltrate. By ignoring the location of the infiltrate, the agreement became 157/171 (91.8%) reports and 946/1026 (92.2%) terms. Thus, natural language processing offers a practical alternative for using free-text reports to determine patient eligibility for computerized clinical practice guidelines.