Increased prevalence of primary drug-resistant pulmonary tuberculosis in immunocompromised patients

Drug-resistant tuberculosis (DR-TB) is difficult and expensive to treat, and is associated with a higher rate of mortality. We conducted a long-term survey to compare the prevalence of primary drug-resistance, adverse effects of drugs and duration of treatment in immunocompetent and immunocompromised patients. Factors associated with primary drug resistance were also investigated.

The patients studied had culture-confirmed pulmonary TB but had not previously received anti-TB treatment. These patients were divided into immunocompetent (IMCPe) and immunocompromised (IMCPr) groups. Baseline data, the prevalence of DR-TB, duration of treatment and adverse effects of drugs were analysed. The rates of resistance to individual first-line anti-TB drugs in the two groups and in subgroups of the IMCPr group were calculated. Multinomial regression analysis was performed to investigate the risk factors associated with primary DR-TB.

Among the 394 patients, 159 (40.4%) were in the IMCPr group. The baseline data for the two groups were similar, except that the IMCPr group was slightly older. The prevalence of drug-resistance was higher in the IMCPr group (25.8% vs 17.0%, OR 1.69, 95% CI: 1.04-2.77), especially for isoniazid, rifampicin and streptomycin, and patients with liver cirrhosis, malignancies and those receiving immunosuppressants. The incidence of adverse drug effects was similar in the IMCPr and IMCPe groups. Multinomial regression analysis showed that being in the IMCPr group, and especially treatment with immunosuppressants, were independent risk factors for DR-TB.

Immunocompromised patients with underlying diseases had an increased prevalence of primary pulmonary DR-TB but a similar incidence of drug-related adverse effects. Diagnosis and investigation of drug-resistance is important before initiating anti-TB treatment in this group of patients.