Progress Toward the Elimination of Tuberculosis -- United States, 1998

In 1998, a total of 18,361 tuberculosis (TB) cases were reported from the 50 states and the District of Columbia, a decrease of 8% from 1997 and 31% from 1992, the height of the TB resurgence in the United States (1,2). The 1998 rate of 6.8 per 100,000 population was 35% lower than in 1992 (10.5) but remained above the national goal for 2000 of 3.5 (3) (Table 1). This report summarizes national TB surveillance data for 1998 and compares them with similar data from previous years. The findings indicate that the overall number of TB cases continued to decrease, and that trends in the number of reported cases and TB incidence varied by geographic area and population characteristics.

All states reported at least one case in 1998, and 18 states reported less than 100 cases. Among the states reporting less than 100 cases in 1998, 17 reported less than 100 cases in 1992, and 14 had no change or a decrease in the number of reported cases in 1998 compared with 1992 (Table 1). Among all states, the proportion of counties reporting no TB cases increased from 42% in 1992 to 49% in 1998; these counties represented 11% of the total U.S. population in 1998. The 1998 TB rate in 19 states was lower than the 2000 national goal (3).

California, Florida, Illinois, New York, and Texas reported the highest number of cases in 1998 and represented 54% of all reported TB cases. During 1992-1998, the five states observed a marked decrease in the number of new cases and together accounted for 68% of the overall decrease. The four cities with the highest number of TB cases were New York (1558), Los Angeles (544), Chicago (473), and Houston (424). The number of reported cases in all four cities decreased between 1992 and 1998: 59% in New York, 51% in Los Angeles, and 41% in Chicago and Houston, and together these cities accounted for 41% of the overall decline in the number of reported TB cases in the United States.

The number of reported TB cases in 1998 compared with 1992 decreased in both sexes and all age groups at varying rates (Table 2). The largest decrease occurred among children aged less than 15 years and adults aged 25-44 years. During 1992-1998, the number of cases in U.S.-born persons decreased 44%, and the number of cases in foreign-born persons increased 4%. The proportion of TB cases among foreign-born persons steadily increased, from 27% in 1992 to 42% in 1998. The TB rate in foreign-born persons remained approximately four to six times higher than for U.S.-born persons. In 1998, among the 7591 TB cases in foreign-born persons, the birth countries with the highest number of cases were Mexico with 1757 (23%), Philippines with 968 (13%), and Vietnam with 748 (10%).

In 1993, CDC began to collect drug susceptibility results for initial Mycobacterium tuberculosis isolates on the TB case report. During 1998, results were reported for 91% (13,477 of 14,830 culture-positive cases). Overall, 1086 (8.1%) case-patients had isolates resistant to at least isoniazid, and 150 (1.1%) had isolates resistant to at least isoniazid and rifampin (i.e., multidrug-resistant TB [MDR-TB]); New York (38) and California (36) reported 49% of the MDR-TB cases. During 1993-1998, resistance to isoniazid decreased slightly (from 8.9% in 1993), and MDR-TB decreased markedly (from 2.8% in 1993). The decrease in MDR-TB reflected declines from 2.7% to 0.7% in U.S.-born persons and from 3.0% to 1.6% in foreign-born persons. As a result, the proportion of MDR-TB cases among foreign-born persons increased from 31% in 1993 to 61% in 1998. Forty-five states and the District of Columbia reported at least one MDR-TB case during 1993-1998.

In 1993, CDC began collecting information about human immunodeficiency virus (HIV) status on TB case reports; 48 states submit HIV test results on TB case reports. In 1998, 3509 (55%) of 6365 TB case reports for persons aged 25-44 years included information about HIV status, an increase from 1993 when 33% had HIV status. Among the states with information for greater than or equal to 75% of the cases in this age group, the proportion of TB cases in HIV-infected persons ranged from 0% (Montana, North Dakota, Vermont, and Wyoming) to 47% (Florida).

Reported by: Div of Tuberculosis Elimination, National Center for HIV, STD, and TB Prevention; and an EIS Officer, CDC.

Editorial Note:

The decline in the overall number of reported TB cases reflects the apparent strengthening of TB-control programs nationwide, particularly in states and cities with the largest number of cases. Supporting this inference are data indicating that the largest decreases in cases among U.S.-born persons during 1993-1994 occurred in areas that reported the largest increases in measures associated with effective TB control: completion of therapy, conversion of patients' sputum from positive to negative, and number of contacts per case-patient (4). These improvements occurred in the same cities that had the largest increases in cases during the TB resurgence.

The elimination of TB in the United States will depend increasingly on eliminating TB among persons born in countries with high TB rates (5). Because the percentage of reported TB cases among foreign-born persons continues to increase, CDC, in collaboration with local and state health departments, updated recommendations to prevent and control TB among foreign-born persons (5). Priority is placed on case-finding, completion of treatment for active TB, contact tracing, screening, and completion of preventive therapy for high-risk groups. Because rates of TB differ among countries, local TB-control staff should develop epidemiologic profiles to identify groups of foreign-born persons at high risk for TB.

Although the number and proportion of MDR-TB cases decreased markedly during 1993-1998, MDR-TB remains a serious concern. One MDR-TB case can challenge the resources and effectiveness of a TB program, and nearly every state has reported at least one MDR-TB case since 1993. Incidence of MDR-TB is increasing in eastern Europe, Asia, and Africa (6), and will continue to affect the clinical management and contact investigations of foreign-born TB patients who are at risk for resistant TB strains.

Incomplete reporting of HIV to the national TB surveillance system leads to underestimates of the incidence of HIV among TB cases. Incomplete reporting has made it necessary to estimate the proportion of TB cases in HIV-infected persons based on TB and acquired immunodeficiency syndrome registry matching (7-9). Using registry match data to supplement HIV test results submitted on the TB case report, minimum estimates of the proportion of TB cases with HIV infection ranged from 15% during 1993-1994 to 10% in 1997 for persons of all ages and from 29% to 21%, respectively, for persons aged 25-44 years (CDC, unpublished data, 1999). CDC and state and local health departments are collaborating to improve HIV testing and reporting for TB patients.

Although TB rates have been decreasing since 1992, the TB elimination goal of 3.5 cases per 100,000 by 2000 and less than 1 case per 1,000,000 population by 2010 are unlikely to be achieved at the current rate of decrease (3). The Advisory Council for the Elimination of TB (ACET), which provides advice and recommendations for eliminating TB to the U.S. Department of Health and Human Services and CDC, recently reassessed its 1989 plan and published updated recommendations for TB elimination in the United States (10). To move from TB control to TB elimination, ACET recommends new and improved diagnostic and treatment methods, and prevention efforts that include establishing broad-based partnerships with public health programs, community-based organizations, and managed-care plans. TB elimination in the United States requires global commitment. Dedication to the goal of TB elimination is critical to sustain the progress evidenced by declining TB morbidity in the United States.

References

1. CDC. Tuberculosis morbidity--United States, 1997. MMWR 1998;47:253-7.
2. CDC. Tuberculosis morbidity--United States, 1992. MMWR 1993;42:363.
3. CDC. A strategic plan for the elimination of tuberculosis in the United States. MMWR 1989;38(no. S-3).
4. McKenna MT, McCray E, Jones JL, Onorato IM, Castro KG. The fall after the rise: tuberculosis in the United States, 1991 through 1994. Am J Public Health 1998;88:1059-63.
5. CDC. Recommendations for prevention and control of tuberculosis among foreign-born persons: report of the Working Group on Tuberculosis Among Foreign-born Persons. MMWR 1998;47(no. RR-16).
6. Pablos-Mendez A, Raviglione MC, Laszlo A, et al. Global surveillance for antituberculosis-drug resistance, 1994-1997. N Engl J Med 1998;338:1641-9.
7. Burwen DR, Bloch AB, Griffin LD, Ciesielski CA, Stern HA, Onorato IM. National trends in the concurrence of tuberculosis and acquired immunodeficiency syndrome. Arch Intern Med 1995;155:1281-6.
8. Moore M, McCray E, Onorato IM. Cross-matching TB and AIDS registries: TB patients with HIV co-infection, United States, 1993-1994. Public Health Rep 1999;114:269-77.
9. Moore M, McCray E, Onorato IM. Trends in TB in the United States, 1993-1997 [Abstract]. Presented at the 29th World Conference of the International Union Against Tuberculosis and Lung Disease, Bangkok, Thailand, November 23-26, 1998.
10. CDC. Tuberculosis elimination revisited: obstacles, opportunities, and a renewed commitment. Advisory Council for the Elimination of Tuberculosis (ACET). MMWR 1999;48(no. RR-9).

TABLE 1. Number of reported tuberculosis cases, percentage change in number of
cases, and rates*, by state and year -- United States, 1992 and 1998
================================================================================
                          No. Cases        % Change        Rate
                       ---------------       from       -----------
State                   1992     1998    1992 to 1998   1992   1998
-------------------------------------------------------------------
Alabama                   418      381        -9%       10.1    8.8
Alaska                     57       55        -4%        9.7    9.0
Arizona                   259      254        -2%        6.8    5.4
Arkansas                  257      171       -33%       10.7    6.7
California              5,382    3,852       -28%       17.4   11.8
Colorado                  104       79       -24%        3.0    2.0
Connecticut               156      128       -18%        4.8    3.9
Delaware                   55       36       -35%        8.0    4.8
District of Columbia      146      107       -27%       24.8   20.5
Florida                 1,707    1,302       -24%       12.7    8.7
Georgia                   893      631       -29%       13.2    8.3
Hawaii                    273      181       -34%       23.5   15.2
Idaho                      26       14       -46%        2.4    1.1
Illinois                1,270      850       -33%       10.9    7.1
Indiana                   247      188       -24%        4.4    3.2
Iowa                       49       55        12%        1.7    1.9
Kansas                     56       56         0%        2.2    2.1
Kentucky                  402      179       -55%       10.7    4.5
Louisiana                 373      380         2%        8.7    8.7
Maine                      24       13       -46%        1.9    1.0
Maryland                  442      324       -27%        9.0    6.3
Massachusetts             428      282       -34%        7.1    4.6
Michigan                  495      385       -22%        5.2    3.9
Minnesota                 165      161        -2%        3.7    3.4
Mississippi               281      225       -20%       10.7    8.2
Missouri                  245      184       -25%        4.7    3.4
Montana                    16       20        25%        1.9    2.3
Nebraska                   28       31        11%        1.7    1.9
Nevada                     99      128        29%        7.5    7.3
New Hampshire              18       14       -22%        1.6    1.2
New Jersey                984      640       -35%       12.6    7.9
New Mexico                 88       68       -23%        5.6    3.9
New York                4,574    2,000       -56%       25.2   11.0
North Carolina            604      498       -18%        8.8    6.6
North Dakota               11       10        -9%        1.7    1.9
Ohio                      358      230       -36%        3.2    2.1
Oklahoma                  216      198        -8%        6.7    5.9
Oregon                    145      156         8%        4.9    4.8
Pennsylvania              758      448       -41%        6.3    3.7
Rhode Island               54       63        17%        5.4    6.4
South Carolina            387      286       -26%       10.7    7.5
South Dakota               32       23       -28%        4.5    3.1
Tennessee                 527      439       -17%       10.5    8.1
Texas                   2,510    1,820       -27%       14.2    9.2
Utah                       78       52       -33%        4.3    2.5
Vermont                     7        5       -29%        1.2    0.8
Virginia                  457      339       -26%        7.2    5.0
Washington                306      265       -13%        6.0    4.7
West Virginia              92       42       -54%        5.1    2.3
Wisconsin                 106      109         3%        2.1    2.1
Wyoming                     8        4       -50%        1.7    0.8

Total                  26,673   18,361       -31%       10.5    6.8
-------------------------------------------------------------------
* Per 100,000 population.
================================================================================

TABLE 2. Number of reported tuberculosis cases, percentage change in number of
cases, and rates*, by sex, age, and year -- United States, 1992 and 1998
==============================================================================================
                     No. reported cases     % Change       Rate
                     -------------------      from      -----------
Characteristic        1992         1998   1992 to 1998  1992   1998
-------------------------------------------------------------------
Sex+
  Male               17,433        11,413    -34.5%     14.0    8.6
  Female              9,236         6,935    -24.9%      7.1    5.0
Age group (yrs)+
   0-14               1,707         1,082    -36.6%      3.1    1.9
  15-24               1,974         1,548    -21.6%      5.5    4.2
  25-44              10,444         6,365    -39.1%     12.7    7.6
  45-64               6,487         4,973    -23.3%     13.4    8.7
   >=65               6,025         4,393    -27.1%     18.7   12.8

Total                26,673        18,361    -31.2%     10.5    6.8
-------------------------------------------------------------------
* Per 100,000 population.
+ Persons were excluded for whom sex (four in 1992 and 13 in 1998) and age (36 in 1992) were
  not reported.
==============================================================================================

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