Initial Drug Regimens for the Treatment of Tuberculosis: Statistical Analysis

Initial Drug Regimens for the Treatment of Tuberculosis: Statistical AnalysisThe correlation coefficient between the proportion of isoniazid-resistant patients and the proportion of patients who were given fewer than four drugs initially at a county level was computed using Spearman’s rank-order method. Logistic regression was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for patients who were initially treated with fewer than four drugs. Both univariate and multivariate analyses were performed to compute crude and adjusted ORs, respectively. Because a large proportion of TB patients had missing data for injecting drug use, excessive alcohol use, and HIV status, an “unknown” category was created to calculate the risk of inadequate initial drug regimens associated with these variables. For HIV status, the “unknown” category included all TB patients who were not tested for HIV antibody or who did not know their HIV status even if previously tested. Statistical analyses were performed using the SAS statistical software program (SAS Institute Inc; Cary, NC). canadian neighbor pharmacy online

In 1994 and 1995, 1,345 of the 1,703 TB patients (80%) reported and verified in New Jersey were culture-positive. Among the 1,345 culture-positive patients, 115 were excluded from this study because their isolates had not been tested for isoniazid susceptibility or they were dead at diagnosis, and therefore not eligible for the evaluation of initial drug regimens. Of the 1,230 remaining patients in this study, 127 (10.3%) had isolates resistant to isoniazid. The proportion of isoniazid-resistant TB changed very little during the study, decreasing from 10.7% in 1994 to 10.0% in 1995 (Table 1). The proportion of TB patients who were initially treated with fewer than four drugs was relatively stable during those 2 years (36.4% and 34.7%, respectively). Among the 437 patients initially treated with fewer than four drugs, 243 of them (55.6%) were initially given the three-drug regimen (isoniazid, rifampin, and pyrazinamide) recommended by ATS/ CDC, accounting for 19.8% of the 1,230 patients (Table 1). Of the 793 patients initially treated with four or more drugs, 670 (84.5%) were prescribed the four-drug regimen (isoniazid, rifampin, pyrazinamide, and either ethambutol or streptomycin) recommended by ATS/CDC. These patients represent 54.5% of the total patient population.
Table 1—Isoniazid Resistance and Initial Drug Regimens for the Treatment of TB in New Jersey, 1994 to 1995

Year No. of Cases Isoniazid Resistance, % Patients Initially Treated With Each Regimen, %
<4 Drugs ATS-3 ATS-4
1994 601 10.7 36.4 20.5 52.1
1995 629 10.0 34.7 19.1 56.8
Total 1,230 10.3 35.5 19.8 54.5

Category: Tuberculosis

Tags: initial drug regimen, physician practice, treatment, tuberculosis