A prospective cohort study investigated whether baseline serum C-reactive protein (CRP), an inexpensive marker of systemic inflammation, predicts poor clinical outcomes in adults with tuberculous meningitis (TBM), particularly among people living with HIV. Participants were enrolled between March 2021 and November 2023 at Mulago and Kiruddu National Referral Hospitals in Kampala, Uganda. The study aimed to evaluate the prognostic value of CRP for disability or death after TBM treatment.
Adults aged 18 years or older with definite, probable, or possible TBM according to the uniform case definition were included. Microbiological confirmation was based on positive cerebrospinal fluid (CSF) Xpert MTB/RIF Ultra or mycobacterial culture. Participants presenting within 3 months of antiretroviral therapy initiation were classified as having unmasking immune reconstitution inflammatory syndrome (IRIS). All participants were enrolled through the HARVEST phase 3 randomized clinical trial, which compared high-dose rifampicin (35 mg/kg/day) with standard-dose rifampicin (10 mg/kg/day) for 8 weeks. All patients received dexamethasone starting at 0.4 mg/kg/day with tapering over 6 weeks. Baseline serum CRP was measured, typically within 24 hours of diagnostic lumbar puncture, using a Cobas c311 clinical chemistry analyzer. The primary outcome was poor neurological outcome, defined as a modified Rankin Scale (mRS) score of 4 or greater at 8 weeks.
Among 178 enrolled adults with TBM, 135 (75.8%) had both baseline CRP measurements and 8-week outcome data available for analysis. The median age was 36 years (IQR, 30 to 42), 46% were female, and 83% were living with HIV, with a median CD4 count of 79 cells/μL (IQR, 38 to 177). Altered mental status at presentation was common, occurring in 76% of participants. As a continuous predictor, baseline CRP demonstrated moderate discrimination for poor outcome, with an area under the receiver operating characteristic curve (AUC) of 0.70 (95% CI, 0.61 to 0.79), improving to 0.76 (95% CI, 0.68 to 0.84) after adjustment for rifampicin dose, TBM diagnostic certainty, Medical Research Council (MRC) severity grade, and HIV status. A CRP threshold of 40 mg/L provided the best balance between sensitivity (66%) and specificity (64%) for predicting mRS ≥4 at 8 weeks. Severe TBM (MRC grade 3) was more common among participants with CRP ≥40 mg/L than among those with lower CRP levels (33% vs 9%). Among participants with poor outcomes (mRS ≥4), 61.2% had baseline CRP ≥40 mg/L compared with 30.9% among those with better outcomes (mRS ≤3). Baseline CRP ≥40 mg/L was associated with a more than threefold increase in the odds of disability or death at 8 weeks (unadjusted OR, 3.53; 95% CI, 1.73 to 7.19; P < .001). This association remained significant after adjustment for potential confounders (adjusted OR, 2.78; 95% CI, 1.28 to 6.04; P = .010). The association did not differ significantly according to TBM diagnostic certainty or suspected unmasking TBM-IRIS status.
Elevated baseline serum CRP was independently associated with a substantially increased risk of disability or death at 8 weeks among adults with TBM, supporting its potential role as a low-cost prognostic biomarker. As an observational cohort analysis nested within a randomized clinical trial, the study provides moderate-level evidence for prognostic utility but does not establish causality. Important limitations include the relatively small sample size, missing CRP or outcome data in a subset of enrolled participants, and restriction to Ugandan referral hospitals, which may limit generalizability to other settings.
Source: Tugume L, Cresswell FV, Engen NW, Tukundane A, Kimuda S, Mugabi T, Namombwe S, Kagimu E, Kabahubya M, Ellis J, Bahr NC. Prognostic value of C-reactive protein in adults with tuberculous meningitis: a prospective cohort study. Clinical Infectious Diseases. 2025 Nov 15;81(5):e410-3.