Decision analysis, public health policy, and isoniazid chemoprophylaxis for young adult tuberculin skin reactors

Abstract

To the Editor.— Analyses of the risk benefit of isoniazid chemopreventive therapy like the recent thoughtful presentation by Colice 1 are welcome and badly needed. However, because of certain assumptions, I believe that he overstated the justification for giving isoniazid chemopreventive therapy to many patients and understated for others. On the basis of limited data, the author calculated that the case-fatality rate for isoniazid-related hepatitis was zero with the 95% confidence intervals being 0% to 3.5%. In his comments, he pointed out that the available data supporting this contention are actually quite scanty, that the case-fatality rate is a key variable, and that giving isoniazid is not the preferred strategy when the rate is above 1%. One of the sources 2 of data for his calculated value of zero should not have been included, since the patients in that study had monthly tests of liver enzymes to protect against isoniazid