[Retrospective cohort study of risk factors for adverse effects of antituberculous therapy]

This study was designed to identify clinical risk factors for adverse effects of antituberculous therapy and their frequency.

A retrospective study of cohorts was undertaken from April 2004 to March 2007. We analyzed the clinical records of 861 patients with tuberculosis treated at Higashi Nagoya Hospital. The factors that were associated with adverse effects in univariate analysis (P < 0.1) were then subjected to multivariate Cox regression analysis for calculation of the hazard ratios (HRs) and their 95% confidence intervals (95% CIs).

Suspension of antituberculous therapy was necessary because of adverse effects in 247 patients (28.7%). The chief adverse effects leading to discontinuation of treatment were liver dysfunction (12.9%), skin rash (6.7%), and gastrointestinal dysfunction (4.1%), while other effects accounted for less than 5.0% of discontinuations. Risk factors for liver dysfunction according to Cox proportional hazards analysis were HCV infection (HR 2.86; 95% CI 1.59 to 5.15; p < 0.001); hepatocellular damage at admission (HR 2.06; 95% CI 1.25 to 3.39; p = 0.005) and high-dose isoniazid (increase per mg/kg: HR 1.36; 95% CI 1.18 to 1.56; p < 0.001). Collagen disease was a risk factor for skin rash (HR 6.06; 95% CI 2.81 to 13.05; p < 0.001). Risk factors for gastrointestinal dysfunction were a high body mass index (increase per kg/m2: HR 0.80; 95% CI 0.71 to 0.91; p < 0.001) and advanced age (increase per year: HR 1.03; 95% CI 1.01 to 1.06; p 0.018).

Adverse effects may lead to substantial additional medical costs because of the need for more medications and tests, as well as a longer hospital stay. Identification of the risk factors for adverse effects of antituberculous therapy should help to minimize such events in tuberculosis patients.