High Completion Rates for TB Therapy Possible Without 100 Percent Direct Observation Treatment (DOT) Rates

Analysis of cities with differing TB therapy completion rates

Researchers at the Joseph L. Mailman School of Public Health at Columbia University investigated completion rates of tuberculosis (TB) therapy from 1990 to 1994.

The study was funded at the point at which federal health policy adopted Directly Observed Therapy (a method of medication administration in which a health care provider or other observer watches the patient take each dose of a drug) as the standard for TB therapy because many patients were not completing therapy.

Investigators examined 28 jurisdictions with 100 or more TB cases in any year between 1990 and 1993. They analyzed therapy-completion rates and rates of Directly Observed Therapy (DOT) for each jurisdiction.

Key Findings

  • In 1990, the median 12-month completion rate was 80.2 percent, but there were wide variations. Those jurisdictions with the highest treatment-completion rates tended to have the smallest number of cases, and vice versa. New York, Chicago, Miami, and Houston, which ranked first, third, fourth, and fifth in cases of TB, ranked at or near the very bottom of completion rates.

  • In 1990, the median DOT rate for the 27 jurisdictions with DOT data was only 13.5 percent. However, there was considerable diversity in DOT rates in every group. For example, in the high-treatment completion group, DOT rates ranged from 100 percent to 0 percent.

  • Overall, treatment-completion rates rose from 71 percent in 1990 to 86 percent in 1994. This improvement was almost entirely in the group with the lowest completion rates.

  • Between 1990 and 1994, DOT rates rose from 13.5 percent to 38.8 percent. However, increased DOT rates did not always correlate with increased completion rates.

    In the high-completion group, although the overall DOT rate rose from 15.7 percent to 66.8 percent, median completion rates rose only .3 percent. In the intermediate group, DOT rates increased overall from 25 percent to 34.9 percent, and treatment-completion rates from 80.4 percent to 86.1 percent, but in some jurisdictions (Detroit, Honolulu, and Washington, D.C.), DOT rates increased significantly, but completion rates changed little.

    In the low-completion group, overall completion rates went from 58 percent to 83 percent, while DOT rates rose almost sixfold from 7.4 percent to 43.9 percent, but in no case to near a 100 percent level.