Epidemiological basis of tuberculosis eradication. 7. Application of life-table methods for assessing the prognosis for tuberculosis patients.

The experience of a group of patients, observed in a follow-up study, may conveniently be described by means of decrement tables, of which the survival table is the best known. Just as this table shows how a population group has decreased gradually because of death, so other decrement tables may depict the cumulative effect of cure, or of death and cure combined.Decrement tables can be established not only when all patients under study have been observed from the onset of their disease until cure or death, but also when patients with varying durations of disease have been followed for only a few years; in this case the statistical technique used for the construction of life-tables must be applied.This paper demonstrates in detail the tabulations and calculations involved in this technique, using nationwide data from the Danish Tuberculosis Register as the basis, and applying the technique to aspects of the prognosis for tuberculosis patients that have hitherto been difficult to quantify.