Epidemiology of adult meningitis during antiretroviral therapy scale-up in southern Africa: Results from the Botswana national meningitis survey

OBJECTIVES

Data on meningitis epidemiology in high HIV-prevalence African settings following antiretroviral therapy scale-up are lacking. We described epidemiology of adult meningitis in Botswana over a 16-year period.

METHODS

Laboratory records for adults undergoing lumbar puncture (LP) 2000-2015 were collected, with complete national data 2013-2014. Cerebrospinal fluid (CSF) findings and linked HIV-data were described, and national incidence figures estimated for 2013-2014. Temporal trends in meningitis were evaluated.

RESULTS

Of 21,560 adults evaluated, 41% (8759/21,560) had abnormal CSF findings with positive microbiological testing and/or pleocytosis; 43% (3755/8759) of these had no confirmed microbiological diagnosis. Of the 5004 microbiologically-confirmed meningitis cases, 89% (4432/5004) were cryptococcal (CM) and 8% (382/5004) pneumococcal (PM). Seventy-three percent (9525/13,033) of individuals undergoing LP with identifiers for HIV registry linkage had documented HIV-infection. Incidence of LP for meningitis evaluation in Botswana 2013-2014 was 142.6/100,000 person-years (95%CI:138.3-147.1); incidence of CM was 25.0/100,000 (95%CI:23.2-26.9), and incidence of PM was 2.7/100,000 (95%CI:2.4-3.1). In contrast to previously reported declines in CM incidence with ART roll-out, no significant temporal decline in pneumococcal or culture-negative meningitis was observed.

CONCLUSIONS

CM remained the predominant identified aetiology of meningitis despite ART scale-up. A high proportion of cases had abnormal CSF with negative microbiological evaluation.

Mortality in adult patients with culture-positive and culture-negative meningitis in the Botswana national meningitis survey: a prevalent cohort study

BACKGROUND

CNS infections are a leading cause of HIV-related deaths in sub-Saharan Africa, but causes and outcomes are poorly defined. We aimed to determine mortality and predictors of mortality in adults evaluated for meningitis in Botswana, which has an estimated 23% HIV prevalence among adults.

METHODS

In this prevalent cohort study, patient records from 2004-15 were sampled from the Botswana national meningitis survey, a nationwide audit of all cerebrospinal fluid (CSF) laboratory records from patients receiving a lumbar puncture for evaluation of meningitis. Data from all patients with culture-confirmed pneumococcal and tuberculous meningitis, and all patients with culture-negative meningitis with CSF white cell count (WCC) above 20 cells per μL were included in our analyses, in addition to a random selection of patients with culture-negative CSF and CSF WCC of up to 20 cells per μL. We used patient national identification numbers to link CSF laboratory records from the national meningitis survey to patient vital registry and HIV databases. Univariable and multivariable Cox proportional hazards models were used to evaluate clinical and laboratory predictors of mortality.

FINDINGS

We included data from 238 patients with culture-confirmed pneumococcal meningitis, 48 with culture-confirmed tuberculous meningitis, and 2900 with culture-negative CSF (including 1691 with CSF WCC of up to 20 cells per μL and 1209 with CSF WCC above 20 cells per μL). Median age was 37 years (IQR 31-46), 1605 (50%) of 3184 patients were male, 2188 (72%) of 3023 patients with registry linkage had documentation of HIV infection, and median CD4 count was 139 cells per μL (IQR 63-271). 10-week and 1-year mortality was 47% (112 of 238) and 49% (117 of 238) for pneumococcal meningitis, 46% (22 of 48) and 56% (27 of 48) for tuberculous meningitis, and 41% (1181 of 2900) and 49% (1408 of 2900) for culture-negative patients. When the analysis of patients with culture-negative CSF was restricted to those with known HIV infection, WCC (0-20 cells per μL vs >20 cells per μL) was not predictive of mortality (average hazard ratio 0·93, 95% CI 0·80-1·09).

INTERPRETATION

Mortality from pneumococcal, tuberculous, and culture-negative meningitis was high in this setting of high HIV prevalence. There is an urgent need for improved access to diagnostics, to better define aetiologies and develop novel diagnostic tools and treatment algorithms.

FUNDING

National Institutes of Health, President's Emergency Plan for AIDS Relief, National Institute for Health Research.

Advanced Human Immunodeficiency Virus Disease in Botswana Following Successful Antiretroviral Therapy Rollout: Incidence of and Temporal Trends in Cryptococcal Meningitis

Background

Botswana has a well-developed antiretroviral therapy (ART) program that serves as a regional model. With wide ART availability, the burden of advanced human immunodeficiency virus (HIV) and associated opportunistic infections would be expected to decline. We performed a nationwide surveillance study to determine the national incidence of cryptococcal meningitis (CM), and describe characteristics of cases during 2000-2014 and temporal trends at 2 national referral hospitals.

Methods

Cerebrospinal fluid data from all 37 laboratories performing meningitis diagnostics in Botswana were collected from the period 2000-2014 to identify cases of CM. Basic demographic and laboratory data were recorded. Complete national data from 2013-2014 were used to calculate national incidence using UNAIDS population estimates. Temporal trends in cases were derived from national referral centers in the period 2004-2014.

Results

A total of 5296 episodes of CM were observed in 4702 individuals; 60.6% were male, and median age was 36 years. Overall 2013-2014 incidence was 17.8 (95% confidence interval [CI], 16.6-19.2) cases per 100000 person-years. In the HIV-infected population, incidence was 96.8 (95% CI, 90.0-104.0) cases per 100000 person-years; male predominance was seen across CD4 strata. At national referral hospitals, cases decreased during 2007-2009 but stabilized during 2010-2014.

Conclusions

Despite excellent ART coverage in Botswana, there is still a substantial burden of advanced HIV, with 2013-2014 incidence of CM comparable to pre-ART era rates in South Africa. Our findings suggest that a key population of individuals, often men, is developing advanced disease and associated opportunistic infections due to a failure to effectively engage in care, highlighting the need for differentiated care models.