To compare isoniazid resistant mycobacterium tuberculosis (INHr-TB) treatment outcomes using a biweekly versus daily therapy.METHOD: We retrospectively reviewed all cases of INH resistant and INH-SM resistant TB at a county health department from Dec 1991 to Jan 2003. We included cases with 6 or more months of drug therapy consisting primarily of rifampin(R), pyrazinamide(Z), and ethambutol(E) and active follow up after completion of treatment for 6 months or greater. Fisher exact tests and unpaired t tests were used to assess for statistically significant differences between the biweekly and daily therapy cohorts.
A total of 61 INHr-TB cases were identified. Forty cases met inclusion criteria.Standard daily therapy was given to 17 patients, of which 8 cases were directly observed therapy (DOT), with a mean duration of treatment of 249 days (179–538). Ten cases were pulmonary, 5 were extrapulmonary, and 2 combined. Sputum culture conversion averaged 29 days. Average active follow up was 15 months (6–32) with one patient relapsing 3 months after completion of treatment.Intermittent therapy was given to 23 patients (23 DOT), either biweekly(22) or triweekly(1) with a mean duration of therapy of 230 days (179–391). Sixteen were pulmonary, 5 extrapulmonary, and 2 combined. Two patients were converted to daily therapy due to adverse effects. Sputum culture conversion averaged 40 days. Average active follow up was 12 months (6–26) with no relapses or deaths in this group.No statistically significant difference was seen in treatment length, follow up, or outcomes between the two treatment groups.CONCLUSIONS: Compared to traditional daily therapy, biweekly dosing with RZE appears to be equally effective in those that tolerate the higher doses.
Biweekly therapy has the advantage of overall cost savings and patient convenience with equivalent outcomes compared to traditional daily therapy.
R. Browning, None.