Outcomes of contact investigations of infectious tuberculosis patients

The objective of this study was to describe outcomes of tuberculosis (TB) c ontact investigations, factors correlated with those outcomes, and current successes and ways to improve TB contact investigations. We abstracted clin ic records of a representative U.S. urban sample of 1,080 pulmonary, sputum -smear(+) TB patients reported to CDC July 1996 through lune 1997 and the c ohort of their 6,225 close contacts. We found a median of four close contac ts per patient. Fewer contacts were identified for homeless patients. A vis it to the patient's residence resulted in two additional (especially child) contacts identified. Eighty-eight percent of eligible contacts received tu berculin skin tests (TSTs). Recording the last exposure date to the infecti ous patient facilitated follow-up TST provision. Thirty-six percent of cont acts were TST(+). Household contacts and contacts to highly smear(+) or cav itary TB patients were most likely to be TST(+). Seventy-four percent of TS T(+) contacts started treatment for latent TB infection (LTBI), of whom 56% completed. Sites using public health nurses (PHNs) started more high-risk TST(-) contacts on presumptive treatment for LTBI. Using directly observed treatment (DOT) increased the likelihood of treatment completion. We docume nted outcomes of contact investigation efforts by urban TB programs. We ide ntified several successful practices, as well as suggestions for improvemen ts, that wilt help TB programs target policies and procedures to enhance co ntact investigation effectiveness.