Epilepsy and neurocysticercosis in Latin America: a systematic review and meta-analysis

Abstract

Background: The difference in epilepsy burden existing among populations in tropical regions has been attributed to many factors, including the distribution of infectious diseases with neurologic sequels. To define the burden of epilepsy in Latin American Countries (LAC) and to investigate the strength of association with neurocysticercosis (NCC), considered one of the leading causes of epilepsy, we performed a systematic review and meta-analysis of the literature.

Methodology: Studies published until 2012 were selected applying predefined inclusion criteria. Lifetime epilepsy (LTE) prevalence, active epilepsy (AE) prevalence, incidence, mortality, treatment gap (TG) and NCC proportion among people with epilepsy (PWE) were extracted. Median values were obtained for each estimate using random effects meta-analysis. The impact of NCC prevalence on epilepsy estimates was determined using meta-regression models. To assess the association between NCC and epilepsy, a further meta-analysis was performed on case-control studies.

Principal findings: The median LTE prevalence was 15.8/1,000 (95% CI 13.5-18.3), the median AE prevalence was 10.7/1,000 (95% CI 8.4-13.2), the median incidence was 138.2/100,000 (95% CI 83.6-206.4), the overall standardized mortality ratio was 1.4 (95% CI 0.01-6.1) and the overall estimated TG was 60.6% (95% CI 45.3-74.9). The median NCC proportion among PWE was 32.3% (95% CI 26.0-39.0). Higher TG and NCC estimates were associated with higher epilepsy prevalence. The association between NCC and epilepsy was significant (p<0.001) with a common odds ratio of 2.8 (95% CI 1.9-4.0).

Significance: A high burden of epilepsy and of NCC in LAC and a consistent association between these two diseases were pointed out. Furthermore, NCC prevalence and TG were identified as important factors influencing epilepsy prevalence to be considered in prevention and intervention strategies.

Figure 1. Pooled life-time (LTE), active epilepsy (AE) prevalence (/1,000), NCC prevalence (by CT scan) and 95% confidence intervals in Latin American countries.

*estimates obtained from only one study.

Figure 2. Forest plots for life-time epilepsy prevalence/1,000 (A) and active epilepsy prevalence/1,000 (B) and 95% CI.

Pooled LTE prevalence for all studies (N = 37) was 15.8/1,000 (95% CI 13.5–18.3). Pooled AE prevalence for all studies (N = 21) was 10.7/1,000 (95% CI 8.4–13.2).

Figure 3. Association between cysticercosis and epilepsy in Latin American Countries.

A. Random-effects meta-analysis restricted to studies using EITB (N = 8): common odds ratio (OR) 2.7 (p<0.001). B. Random-effects meta-analysis restricted to studies using brain CT scan (N = 4): common OR 5.6 (p<0.001). C. Random-effects meta-analysis of all the studies (N = 9): common OR (2.8; p<0.001).