Increased prevalence of advanced tuberculosis in rural low tuberculosis caseload counties in North Carolina

Pulmonary tuberculosis (TB) patients reported in North Carolina (NC), USA, from 1996 to 2008 (inclusive).

To compare prevalence of cavitary TB as a surrogate marker for advanced disease in low-caseload counties with high-caseload counties.

A multivariate log binomial regression model was used to estimate prevalence ratios (PRs) for cavitary TB.

The proportion of TB cases in low-caseload counties vs. the total number of TB cases in NC over the study period increased from 10% in 1996 to 20% in 2008. After adjusting for human immunodeficiency virus (HIV) status, excess alcohol use and report year, patients in rural areas of low-caseload counties had greater prevalence (PR 1.40, 95%CI 1.19-1.64) of cavitary disease compared with patients from rural areas of high-caseload counties. The prevalence of cavitary TB did not differ between urban residents of high- or low-caseload counties (PR 1.00, 95%CI 0.86-1.16) after adjusting for HIV status, excess alcohol use and report year.

TB patients in rural areas of low-caseload counties presented with more advanced TB disease compared with patients from urban and/or high-caseload counties. Barriers to timely recognition of TB in rural low-caseload settings must be considered in TB control programs.