Introduction
Currently, more than 1.7 billion people (approximately 22% of the world population) have a Mycobacterium tuberculosis (MTB) infection [1]. Tuberculosis (TB) caused 1.5 million deaths in 2020 and is the 13th leading cause of death worldwide. Age is a major risk factor for pulmonary TB [2] and is associated with a longer treatment delay and higher mortality rate [3]. Because of the global increase in the aging population, TB must be diagnosed and treated quickly. However, the risk of adverse reactions during anti-TB treatment is higher in older adults, especially in patients receiving rifampin (RIF) or pyrazinamide (PZA) [4, 5]. The situation is worse in Taiwan because Taiwan’s population is aging at a rate more than twice that in Western countries [6]. The occurrence of adverse reactions may compromise drug adherence and worsen anti-TB treatment outcomes [7].
Acute kidney injury (AKI) is a rare and severe complication that can interrupt anti-TB treatment and cause permanent kidney damage [8]. Among first-line anti-TB drugs, the most common offending drug for AKI is RIF [8-10]. However, other drugs, such as isoniazid (INH) and ethambutol (EMB), are also associated with AKI [11, 12]. So far prospective studies evaluating the incidence of AKI during anti-TB treatment have not been conducted. Retrospective cohort studies on TB treatment have reported an AKI incidence of approximately 0.05% to 7.1% [13, 14]. However, these studies have not followed renal function regularly, and one study performed a laboratory survey only when patients exhibited gastrointestinal (such as nausea and vomiting) or flu-like symptoms [15]. Furthermore, the definition of kidney injury has differed between these studies [8, 13, 16]. Predictive factors for AKI, especially in an aging population, also remained unclear. Therefore, we conducted this prospective cohort study to evaluate the incidence of AKI during first-line anti-TB treatment and explored the risk factors for this complication.