Table 4. Multivariable analysis of risk factors for being a RT-PCR positive, culture-negative case-patient, using culture positive patients as controls.

Risk Factor	OR	95% CI	p-value
Hospital 3, 6, or 11	4.3	2.1–8.6	<0.0001
Antibiotic in CSF	12.2	5.9–25.0	<0.0001
Age ≥18 years	2.8	1.3–5.8	0.006
N. meningitidis	3.3	1.5–7.7	0.005

There were a total of 103 case-patients and 142 controls.

OR, odds ratio; CI, confidence interval; CSF, cerebrospinal fluid.