Host Factors Associated with Poor Respiratory Health-Related Quality of Life in Pulmonary Tuberculosis

Background: Despite treatment, up to 70% of pulmonary tuberculosis (PTB) patients have poor Health-related Quality of Life (HrQOL) associated with chronic lung injury. Early identification of these patients may improve clinical care, but data are lacking.

Methods: New adult drug-susceptible PTB cases presenting to the DOTS clinics in Pune and Chennai, India, since October 2014 were enrolled and evaluated at anti-tuberculosis treatment (ATT) initiation, two months of ATT and ATT completion. Those with a history of chronic lung diseases were excluded. HrQOL was assessed by the Saint Georges Respiratory Questionnaire (SGRQ); a multi-domain questionnaire validated for respiratory diseases. Higher SGRQ scores indicate worse respiratory HrQOL; and correlate with airflow limitation, functional impairment and hypoxemia. The minimum clinically important difference in SGRQ scores has been determined to be four points. Associations between host factors during early ATT and SGRQ scores at ATT completion were measured using random effects regression models.

Results: 147 participants completed ATT by April 2016 and had SGRQ scores available for analysis. Median age was 39 years (IQR 27-48), 66% were males, 11% were HIV coinfected, 21% had diabetes mellitus and 37% smoked. Mean (SD) total SGRQ scores at ATT initiation, two months of ATT and ATT completion were 48 (21), 27 (20) and 15 (14) respectively (p<0.001 for difference in means). Participants aged 50 years and older had at least a four point higher total SGRQ score at ATT completion than their younger counterparts (p=0.01). Random effects regression models adjusted for age, sex, smoking and total SGRQ scores at ATT initiation identified older age (aOR=1.63 per 10-year increment; p=0.02) and higher total SGRQ scores at two months of ATT (aOR=1.13 per 4-point increment; p=0.04) as independent predictors of having total SGRQ scores in the highest quartile despite ATT completion.

Conclusion: Older patients, and those with higher SGRQ scores at two months of ATT, had worse HrQOL despite ATT completion and may benefit from interventions to limit chronic pulmonary sequelae of TB. Studies exploring the underlying mechanisms of lung injury, especially during the first two months of ATT, may inform adjuvant therapies for reducing pulmonary morbidity.