Adequacy of the Initial Drug Regimens for the Treatment of Drug-Resistant TR
In 1994 and 1995, 207 of the 1,230 patients (16.8%) had isolates resistant to at least one of the antituberculosis drugs. Among the 207 patients, 131 had isolates resistant to one drug only, 37 had resistance to at least isoniazid and rifampin (MDRTB), and 39 had resistance to two or more other dmgs (Table 3). The adequacy of the initial drug regimens for the treatment of these drug-resistant patients was evaluated by the number of drugs to which a TB isolate was susceptible. This is referred to in Table 3 as the “number of effective drugs.” Overall, 13 of these patients (6.3%) were treated inadequately, with only one or no effective drugs included in their initial regimens. Fifty-nine of the 207 patients (28.5%) were treated with two effective drugs. Because of documented drug resistance in these patients, two “effective” dmgs may still be inadequate. Ten of the 37 MDRTB patients (27%) were not treated adequately and 16 (43%) might not have been treated appropriately.
This study is based on TB surveillance data collected in New Jersey. In addition to the variables required by CDC, information on initial care providers was also collected and analyzed to investigate the relationship between initial dmg regimens and initial care providers. The results showed that a substantial proportion of TB patients were not treated with the initial four-drug regimen recommended by ATS/ CDC. A large proportion of MDRTB patients were not initially treated with the appropriate number of effective drugs. The type of practice setting for the initial care provider was found to be the most important predictor for the use of inappropriate initial drug regimens.

While CDC/ATS made the recommendation of an initial four-drug regimen in 1993 and 1994, it was assumed that the proportion of TB patients who were initially treated with fewer than four drugs should decrease over time. However, little improvement was observed in New Jersey from 1994 to 1995, with the proportion decreasing slightly from 36.4% to 34.7%. Even though an initial four-dmg regimen may not be appropriate under many conditions, an increase in prescribing the regimen should be observed on a population basis if the CDC/ATS recommendation is implemented.
Table 3—Number of Effective Drugs for the Initial Treatment of TB by the Status of Drug Resistance

No. of Patients Who Received a Given No. of Effective Drugs*
Resistance No. of cases 0 or 1 Drug 2 Drugs >3 Drugs
To one drug only 131 3 27 101
To at least isoniazid and rifampin 37 10 16 11
To two or more other drugs 39 0 16 23
Total 207 13 59 135