Effect of missed clinic visits on treatment outcomes among people with tuberculosis: a quasi-experimental study utilizing instrumental variable analysis

Missed clinic visits disrupt the continuity of care and potentially impact tuberculosis (TB) treatment outcomes negatively. We evaluated the effect of missed clinic visits on mortality and treatment success among people with bacteriologically confirmed pulmonary TB in rural eastern Uganda.

Using routine TB clinic data, we designed a quasi-experimental study and used instrumental variable analysis to estimate a cause-effect. The exposure was one or more missed clinic visit(s), the instrumental variable was patient residence in the same sub-county as the TB clinic, and the outcomes were mortality and treatment success. We performed a two-stage least squares logistic regression for causal analysis and reported the odds ratio (OR) and 95% confidence interval (CI).

Of 762 participants with similar baseline characteristics, 186 (24.4%) missed ≥1 clinic visit(s), 342 (44.9%) resided in the same sub-county as the TB clinic, 61 (8.0%) had died, and 687 (90.2%) were successfully treated for TB. Missed clinic visits increased mortality (OR 2.88, 95% CI 1.36-6.13) and reduced TB treatment success (OR 0.41, 95% CI 0.20-0.82).

Missed clinic visits increase mortality and negatively impact treatment success among people with TB. The reasons for missed clinic visits should be identified and tackled through context-specific measures.