Tuberculosis treatment adherence and fatality in Spain

Abstract

Background: The adherence to long tuberculosis (TB) treatment is a key factor in TB control programs. Always some patients abandon the treatment or die. The objective of this study is to identify factors associated with defaulting from or dying during antituberculosis treatment.

Methods: Prospective study of a large cohort of TB cases diagnosed during 2006-2007 by 61 members of the Spanish Society of Pneumology and Thoracic Surgery (SEPAR). Predictive factors of completion outcome (cured plus completed treatment vs. defaulters plus lost to follow-up) and fatality (died vs. the rest of patients) were based on logistic regression, calculating odds ratios (OR) and 95% confidence intervals (CI).

Results: Of the 1490 patients included, 29.7% were foreign-born. The treatment outcomes were: cured 792 (53.2%), completed treatment 540 (36.2%), failure 2 (0.1%), transfer-out 33 (2.2%), default 27 (1.8%), death 27 (1.8%), lost to follow-up 65 (4.4%), other 4 (0.3%). Completion outcome reached 93.5% and poor adherence was associated with: being an immigrant (OR = 2.03; CI:1.06-3.88), living alone (OR = 2.35; CI:1.05-5.26), residents of confined institutions (OR = 4.79; CI:1.74-13.14), previous treatment (OR = 2.93; CI:1.44-5.98), being an injecting drug user (IDU) (OR = 9.51; CI:2.70-33.47) and treatment comprehension difficulties (OR = 2.93; CI:1.44-5.98). Case fatality was 1.8% and it was associated with the following variables: age 50 or over (OR = 10.88; CI:1.12-105.01), retired (OR = 12.26;CI:1.74-86.04), HIV-infected (OR = 9.93; CI:1.48-66.34), comprehension difficulties (OR = 4.07; CI:1.24-13.29), IDU (OR = 23.59; CI:2.46-225.99) and Directly Observed Therapy (DOT) (OR = 3.54; CI:1.07-11.77).

Conclusion: Immigrants, those living alone, residents of confined institutions, patients treated previously, those with treatment comprehension difficulties, and IDU patients have poor adherence and should be targeted for DOT. To reduce fatality rates, stricter monitoring is required for patients who are retired, HIV-infected, IDU, and those with treatment comprehension difficulties.