2015 年 54 巻 18 号 p. 2315-2320
Objective In the 1950s, a high-dose (40-70 mg/kg/day) of pyrazinamide (PZA), was reported to cause drug-induced liver injury (DILI) at an unacceptable frequency. It remains unclear whether adding PZA (Z) at the currently accepted low-dose (20-25 mg/kg/day) for two months to a regimen of isoniazid (H) + rifampicin (R) + ethambutol (E) actually increases the risk of DILI.
Method Smear-positive tuberculosis patients were treated with daily HRE or HRZE regimen under direct observation. We used three independent models. Model 1 was analyzed with a multivariate Cox-analysis using a pre-matched cohort. Next, propensity score matching was conducted using the nearest neighbor method with caliper of 0.03. Models 2 and 3 were analyzed by univariate and multivariate Cox-analyses, respectively, with the matched cohort. DILI was assessed based on the guidelines of the American Thoracic Society.
Results We reviewed the records of 383 patents (male, n=260; female n=123; mean age, 64±20 years). Among these patients, 75 patients were treated with HRE and 308 were treated with HRZE. DILI occurred in the first two months in 24% (18/75) and 8% (24/308) of the HRE-treated and HRZE-treated cases, respectively. In all three of the models, DILI was less frequent in patients treated with the HRZE regimen: Model 1, HR of 0.30 (95% confidence interval (CI) 0.14-0.68, p=0.004); Model 2, HR of 0.37 (95%CI 0.14-0.96, p=0.041); and Model 3, HR of 0.34 (95%CI 0.12-0.94, p=0.038).
Conclusion The addition of the currently accepted low dose (20-25 mg/kg/day) of PZA to the HRE regimen did not increase the incidence of DILI during the first two months of treatment.
