Treatment completion for latent tuberculosis infection in Norway: a prospective cohort study

Yvette Louise Schein,Anne Ma Dyrhol-Riise,Richard A White,Hallgeir Tveiten,Tesfaye Madebo,Trude Margrete Arnesen,Hilde Elise Andersen,Brita Askeland Winje

doi:10.1186/s12879-018-3468-z

Abstract

BackgroundSuccessful treatment of latent tuberculosis infection (LTBI) is essential to reduce tuberculosis (TB) incidence rates in low-burden countries. This study measures treatment completion and determinants of non-completion of LTBI treatment in Norway in 2016.MethodsThis prospective cohort study included all individuals notified with LTBI treatment to the Norwegian Surveillance System for Infectious Diseases (MSIS) in 2016. We obtained data from MSIS and from a standardized form that was sent to health care providers at the time of patient notification to MSIS. We determined completion rates. Pearson’s chi squared test was used to study associations between pairs of categorical variables and separate crude and multivariable logistic regression models were used to identify factors associated with treatment completion and adverse drug effects.ResultsWe obtained information on treatment completion from 719 of the 726 individuals notified for LTBI treatment in 2016. Overall, 91% completed treatment. Treatment completion was highest in the foreign-born group [foreign-born, n = 562 (92%) vs Norwegian-born, n = 115 (85%), p = 0.007]. Treatment completion did not differ significantly between prescribed regimens (p = 0.124). Adverse events were the most common reason for incomplete treatment. We found no significant differences in adverse events when comparing weekly rifapentine (3RPH) with three months daily isoniazid and rifampicin (3RH). However, there were significantly fewer adverse events with 3RPH compared to other regimens (p = 0.037). Age over 35 years was significantly associated with adverse events irrespective of regimen (p = 0.024), whereas immunosuppression was not significantly associated with adverse events after adjusting for other variables (p = 0.306). Treatment under direct observation had a significant effect on treatment completion for foreign-born (multivariate Wald p-value = 0.017), but not for Norwegian-born (multivariate Wald p-value = 0.408) individuals.ConclusionsWe report a very high treatment completion rate, especially among individuals from countries with high TB incidence. The follow-up from tuberculosis-coordinators and the frequent use of directly observed treatment probably contributes to this. Few severe adverse events were reported, even with increased age and in individuals that are more susceptible. While these results are promising, issues of cost-effectiveness and targeting treatment to individuals at highest risk of TB are important components of public health impact.

Highlights

Successful treatment of latent tuberculosis infection (LTBI) is essential to reduce tuberculosis (TB) incidence rates in low-burden countries
The objective of this study is to measure LTBI treatment completion and determinants of non-completion in all individuals notified to Norwegian Surveillance System for Infectious Diseases (MSIS) in 2016
Data included demographic and clinical information available through MSIS, and additional data on treatment completion, adverse events, patient support, and use of healthcare resources collected through a standardized treatment completion form that was sent to prescribing clinicians and TB coordinators at the time the individual was reported to MSIS

Summary

Introduction

Successful treatment of latent tuberculosis infection (LTBI) is essential to reduce tuberculosis (TB) incidence rates in low-burden countries. Norway has a mandatory screening program for TB and LTBI, which includes immigrants from high TB incidence countries, pre-employment screening, and outbreak management [2]. Immigrants > 15 years of age were screened for TB with a chest X-ray. In Norway’s national guidelines, LTBI treatment is strongly recommended for children under the age of 5, contacts, those with fibrotic lesions on chest X-ray, or those with select immunosuppressive conditions (HIV-infection, haemodialysis, solid organ transplants, malignancies, or prior to iatrogenic immunosuppression). LTBI treatment is conditionally recommended for children aged 5–14 years, those with calcifications on chest X-ray, those who are underweight, and individuals with long-term steroid treatment, diabetes mellitus, or drug addiction. Being foreign-born was not considered a single criterion for priority for treatment at the time of the study [3]

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