Data-driven targets for predicting outcomes in patients with HIV infection and tuberculous meningitis in China.

Objectives: For people living with HIV (PLWH) and tuberculous meningitis (TBM), current studies on risk stratification and poor prognosis lack a clear optimal threshold. To address this gap, this study aims to identify an optimal immunological threshold for risk stratification and explore predictors of poor prognosis in this population. Methods: We conducted a multicentre cross-sectional study enrolling PLWH with TBM from hospitals across eight provinces of China between January 2018 and December 2020. We extracted the demographic and clinical data, discharge outcomes, Medical Research Council staging and CD4+ T-lymphocyte count on admission. CD4 thresholds were determined using restricted cubic splines with knots at quintiles. Multivariable logistic regression of risk factors derived adjusted ORs with 95% CIs. Results: A total of 201 participants were included in the study. Of these, 173 (86.1%) improved with treatment. Restricted cubic spline analysis identified CD4+ T-lymphocyte count <50 cells/µL as the optimal threshold for predicting poor TBM outcomes; the median CD4+ count was significantly lower in patients who deteriorated (40 cells/µL) than in those who improved (69 cells/µL). Multivariable logistic regression confirmed CD4+ T-lymphocyte count <50 cells/µL and elevated blood urea nitrogen (BUN) as independent risk factors for adverse outcomes. Conclusions: In PLWH with TBM, a CD4+ T-cell count below 50 cells/µL defines a critical stratification threshold for clinical risk classification, with elevated BUN serving as an additional prognostic marker. These findings support the prioritisation of severely immunocompromised patients for targeted management and further mechanistic studies.