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Background & objectives: The National Tuberculosis (TB) Control Programme has transitioned from thrice-weekly to daily drug treatment regimens in India. This preliminary study was conceived to compare the pharmacokinetics of rifampicin (RMP), isoniazid (INH) and pyrazinamide (PZA) in TB patients being treated with daily and thrice weekly anti-TB treatment (ATT). Methods: This prospective observational study was undertaken in 49 newly diagnosed adult TB patients receiving either daily ATT (n=22) or thrice-weekly ATT (n=27). Plasma RMP, INH and PZA were estimated by high-performance liquid chromatography. Results: The peak concentration (C max ) of RMP was significantly higher (RMP: 8.5 µg/ml vs . 5.5 µg/ml; P =0.003) and C max of INH was significantly lower (INH: 4.8 µg/ml vs . 10.9 µg/ml; P <0.001) in case of daily dosing compared to thrice-weekly ATT. C max of drugs and doses was significantly correlated. A higher proportion of patients had subtherapeutic RMP C max (8.0 µg/ml) during thrice-weekly compared to daily ATT (78% vs . 36%; P =0.004). Multiple linear regression analysis showed that C max of RMP was significantly influenced by the dosing rhythm, pulmonary TB and C max of INH and PZA by the mg/kg doses. Interpretation & conclusions: RMP concentrations were higher and INH concentrations were lower during daily ATT, suggesting that INH doses may need to be increased in case of a daily regimen. Larger studies are, however, required using higher INH doses when monitoring for adverse drug reactions and treatment outcomes.

Background and Objective: India, a highly heterogeneous country, has no common reference standards for predicting spirometry values, with very few recent studies from south India. This study aimed to create reference equations for rural south Indian adults, based on a population-based survey in Vellore, south India and compare it with other equations from India. Methods: The data from 583 non-smoking, asymptomatic participants (30 years and older) from a spirometry-based survey for airflow obstruction (rural Vellore, 2018), were used to develop equations for FEV1, FEV1/FVC, and FVC. The dataset was divided for development (70%) and validation (30%), by gender. Differences between observed and predicted values were assessed using the new equations and comparisons made with other equations from India. Results: Predictions with Vellore rural equations were closest to the previous south Indian equations from urban Bangalore. However, the Bangalore equations led to overestimation of FVC values in males, and of both FEV1 and FVC values in females. Using the rural Vellore equations also led to a higher percent of males being classified as having airflow obstruction, compared to the Bangalore equations which underestimated airflow obstruction in this rural population. Comparison with previously derived Indian equations from other parts of the country showed pronounced variations. Conclusions: Our study reiterates the need for representative rural and urban studies of adults from various parts of India, to obtain region specific reference equations, given the wide variations in spirometry values in “normal” individuals, due to social heterogeneities of the Indian population and resulting complexities in defining normal.

Background: Infections continue to be the leading aetiology of bronchiectasis in developing countries like India. Among non-infectious cases, the majority will have no identifiable cause despite extensive evaluation. Recently, immunodeficiency has been recognized as an important aetiology, but data on its prevalence remain rather sparse. Objectives: The objective of this study is to evaluate the prevalence of humoral immunodeficiency in a cohort of adults with bilateral bronchiectasis with no apparent aetiology. Methods: This is the single-site study from Christian Medical College (Vellore, India) of adults with HRCT-proven non-infectious bronchiectasis. Humoral immunity was assessed through quantitative analysis of immunoglobulins and IgG subclass levels. Results: Among 158 cases, immunoglobulin deficiency was found in 15%. Low IgM was the most predominate finding (7%), followed by common variable immunodeficiency (3%) and low IgA (2.5%). In addition, IgG subclass deficiency was found in 5%. In 53% of cases, no specific aetiology could be identified. Conclusion: Humoral immune deficiency is present in a significant proportion of patients with non-infectious bronchiectasis. Routine measurement of serum immunoglobulins should therefore be considered as part of the evaluation.

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