P-771. Demographic and Clinical Characteristics of Adverse Reactions to anti-Tuberculosis Therapy: A Retrospective Analysis

Abstract Background Adverse reactions (AR) to anti-tuberculosis (anti-TB) therapy pose a significant challenge, leading to decreased treatment compliance, increased morbidity and mortality rates, and prolonged hospital length-of-stay. Methods This study examines the demographic, clinical, and laboratory profiles of patients diagnosed with tuberculosis and hospitalized at the Tor Vergata Policlinic in Rome between 2013-2023, who experienced adverse reactions requiring the interruption, suspension, or modification of anti-tuberculosis therapy, in the period 2013-2023. Results Out of 242 patients receiving treatment for tuberculosis, data regarding AR were available for 136 cases. Of these, 35.3% (48/136) experienced an AR attributable to anti-tuberculosis therapy, median age of 39 years (IQR 26.5-57), 72.9% male, 60.4% non-italians, and 41.6% undergoing treatment for pulmonary TB. The most common AR were hypertransaminasemia (52.2%), allergic reaction (25%), and cholestasis (8.3%). Patients with AR characterized by hypertransaminasemia/cholestasis compared to those with allergic reactions were younger (31 years (IQR 25-45) vs. 60.5 (IQR 36-69.5); p=0.012), more frequently of non-italian nationality (74.2% vs. 25.8%; p= 0.013), and had more frequently a negative Quantiferon test (41.9% vs. 8.3%; p= 0.03). Pirazinamide emerged as the drug most frequently linked to AR, being suspended in 62.5% of cases (20/29 due to hypertransaminasemia; 8/12 due to allergic reaction). In 76.2% of cases, the drug responsible for the AR was discontinued in favor of a fluoroquinolone. All ARs resolved upon suspension of the implicated drug. Among patients with AR, 65.3% recovered, and 13% died. Patients with AR had a lower lymphocyte count at treatment initiation compared to patients without AR (median 1150 (IQR 780-1940) vs 1460 (IQR 1035-2020), p=0.04) and had more frequently a negative Quantiferon test (29.2% vs 10.2%; p=0.012). Conclusion AR during TB therapy affected 35% of patients in our sample. Pyrazinamide was the most commonly implicated drug, and the reactions resolved upon discontinuation. A lower lymphocyte count at TB diagnosis in patients with AR might indicate an immune component, similar to IRIS, in their onset. However, further studies are warranted to explore this aspect. Disclosures All Authors: No reported disclosures