Epidemiological Trends of Drug-Resistant Tuberculosis in China From 2007 to 2014: A Retrospective Study

Abstract

The emergence and spread of drug-resistant tuberculosis (DR-TB) has become the major concern in global TB control nowadays due to its limited therapy options and high mortality. A comprehensive evaluation for the epidemiological trends of DR-TB in mainland China, of which TB incidences remain high, is essential but lacking. This study aimed to describe the trends of DR-TB overtime, especially multidrug-resistant TB (MDR-TB); and to identify unique characteristics of MDR-TB cases compared with drug-susceptible TB cases in Mainland China. We retrospectively analyzed surveillance data collected from 36 TB prevention and control institutions in Shandong Province, China over an 8-year period. Unique characteristics of MDR-TB were identified; Chi-square test for trends and linear regression were used to assess the changes in proportions of different resistance patterns overtime. The overall MDR rate was 6.2% in our sample population. There were no statistically significant changes in the percentage of drug-susceptible, isoniazid (INH) resistance, ethambutol (EMB) resistance, streptomycin (SM) resistance, and MDR TB during our study period except that the overall rifampin (RFP) resistance and rifampin monoresistance (RMR) increased at a yearly rate of 0.2% and 0.1%, respectively. Among those with known treatment histories, a higher MDR rate of 8.7% was observed, in which 53.9% were primary MDR-TB patients, and this rate was increasing at a yearly rate of 4.1% over our study period. MDR-TB patients were more likely to be female (odds ratio [OR], 1.23; 95% confidence interval [CI], 1.05-1.34), aged 25 to 44 years (OR, 1.67; 95%CI, 1.45-1.93), retreated (OR, 11.95; 95%CI, 9.68-14.76), having prior TB contact (OR, 1.89; 95%CI, 1.19-2.78) and having cavity (OR, 1.57; 95%CI 1.36-1.81), or bilateral disease (OR, 1.45; 95%CI 1.19-1.76) on chest radiology. Persistent high levels of MDR-TB, increasing rates of primary MDR-TB and RMR characterize DR-TB cases in mainland China; community-acquired drug resistance may be one of the most modifiable factors in future TB control strategies.

FIGURE 1

Trends of different drug-resistance patterns among 13,486 culture-confirmed TB cases in China, 2007 to 2014. For MDR-TB (χ² = 0.364, P = 0.546); for INH resistance (χ² = 3.637, P = 0.057); for RFP resistance (χ² = 5.106, P = 0.024; linear regression formula: R² = 0.13, x-coefficient = 0.002, SE = 0.075); for EMB resistance (χ² = 0.494, P = 0.482); for SM resistance (χ² = 0.045, P = 0.831). EMB = ethambutol, INH = isoniazid, MDR-TB = multidrug-resistant tuberculosis, RFP = rifampin, SE = standard error, SM = streptomycin, TB = tuberculosis.

FIGURE 2

Trends of the primary MDR-TB proportion among MDR-TB cases in SPCH, 2007 to 2014. (χ² = 21.555, P < 0.001; linear regression formula: R² = 0.677, x-coefficient = 0.041, SE = 0.341). MDR-TB = multidrug-resistant tuberculosis, SE = standard error, SM = streptomycin, SPCH = Shandong Provincial Chest Hospital.