{
  "abstract": "Background People who smoke are at increased risk of unfavourable tuberculosis treatment outcomes compared with those who do not, but the pathways that explain this disparity are unclear.Objective To estimate the difference in a successful end-of-treatment outcome by smoking status among people with multidrug- or rifampicin-resistant tuberculosis (MDR/RR-TB) and to examine if this difference changes if people who smoked had the same retention in treatment as those who did not smoke.Design and methods Using data from the prospective endTB Observational Study, we estimated the difference in treatment success by cigarette smoking status, adjusting for baseline confounders including demographics, social history and comorbidities. To examine how this difference changed if everyone was retained in treatment, we censored participants who were lost to follow-up and applied inverse probability of censoring weights to simulate this scenario.Results Among 1786 participants in 12 countries, 539 (30.2%) reported smoking at least one cigarette daily. People who smoked were more frequently found in post-Soviet countries and had a complex social history (eg, incarceration and substance use) and infectious comorbidities (eg, hepatitis C). At the end of treatment, 73.5% of people who smoked and 80.3% of people who did not smoke had treatment success (risk difference in percentage points: −6.8, 95% CI −11.1 to –2.6). After adjusting for baseline confounders, the risk difference was similar (−5.2 percentage points), but the 95% CI was less precise (−14.1 to 3.2). When simulating a scenario in which everyone was retained in treatment, the risk difference was attenuated (−1.9 percentage points; 95% CI −11.1 to 4.7).Conclusion People who smoked had a lower frequency of MDR/RR-TB treatment success than those who did not smoke. Eliminating loss to follow-up reduced this difference by smoking status, suggesting that pathways related to retention in treatment were a major driver of this disparity.",
  "authors": [
    {
      "affiliations": [
        "Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, USA"
      ],
      "name": "Matthew L Romo"
    },
    {
      "affiliations": [
        "Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, Massachusetts, USA"
      ],
      "name": "Allison LaHood"
    },
    {
      "affiliations": [
        "Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK"
      ],
      "name": "Helen R Stagg"
    },
    {
      "affiliations": [
        "Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, USA",
        "Partners In Health, Boston, Massachusetts, USA",
        "Division of Global Health Equity, Brigham and Women’s Hospital, Boston, Massachusetts, USA"
      ],
      "name": "Carole D Mitnick"
    },
    {
      "affiliations": [
        "Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, USA"
      ],
      "name": "Letizia Trevisi"
    },
    {
      "affiliations": [
        "Médecins Sans Frontières, Paris, France"
      ],
      "name": "Cathy Hewison"
    },
    {
      "affiliations": [
        "Interactive Research & Development, Durban, South Africa"
      ],
      "name": "Shrivani Padayachee"
    },
    {
      "affiliations": [
        "National Hospital Arzobispo Loayza, Lima District, Peru"
      ],
      "name": "Edwin Herrera Flores"
    },
    {
      "affiliations": [
        "Partners In Health, Maseru, Lesotho"
      ],
      "name": "Lawrence Oyewusi"
    },
    {
      "affiliations": [
        "Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK",
        "Interactive Research & Development, Singapore"
      ],
      "name": "Palwasha Y Khan"
    },
    {
      "affiliations": [
        "Epicentre, Paris, France"
      ],
      "name": "Helena Huerga"
    },
    {
      "affiliations": [
        "Epicentre, Paris, France"
      ],
      "name": "Mathieu Bastard"
    },
    {
      "affiliations": [
        "Partners In Health, Boston, Massachusetts, USA",
        "Division of Global Health Equity, Brigham and Women’s Hospital, Boston, Massachusetts, USA"
      ],
      "name": "Michael L Rich"
    },
    {
      "affiliations": [
        "Partners In Health, Addis Ababa, Ethiopia"
      ],
      "name": "Girum Bayissa Tefera"
    },
    {
      "affiliations": [
        "Partners In Health, Almaty, Kazakhstan"
      ],
      "name": "Mahmud Rashitov"
    },
    {
      "affiliations": [
        "Médecins Sans Frontières, Yerevan, Armenia"
      ],
      "name": "Ohanna Kirakosyan"
    },
    {
      "affiliations": [
        "Interactive Research & Development, Jakarta, Indonesia"
      ],
      "name": "Aga Krisnanda"
    },
    {
      "affiliations": [
        "National Tuberculosis Center, Bishkek, Kyrgyzstan"
      ],
      "name": "Atyrkul Toktogonova"
    },
    {
      "affiliations": [
        "Institute of Chest Diseases, Kotri, Pakistan"
      ],
      "name": "Muhammad Rafi Siddiqui"
    },
    {
      "affiliations": [
        "Médecins Sans Frontières, Yangon, Myanmar"
      ],
      "name": "Camilo Gómez-Restrepo"
    },
    {
      "affiliations": [
        "Médecins Sans Frontières, Tbilisi, Georgia"
      ],
      "name": "Tina Kotrikadze"
    },
    {
      "affiliations": [
        "Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, USA"
      ],
      "name": "Molly F Franke"
    },
    {
      "affiliations": [],
      "name": "for the endTB Observational Study Team"
    }
  ],
  "title": "Effect of smoking on drug-resistant tuberculosis treatment outcomes and potential mechanistic pathways: a multicountry cohort study",
  "uid": "6fa87480-a1a9-570a-8377-57eb450e2c85"
}