Infectious Disease
Investigating heterogeneity of effect of albendazole treatment on neurocysticercosis parasite death by host sex, age and immune function indicators Zachary Zuchowski* Zachary Zuchowski Zuchowski Zuchowski Zuchowski Zuchowski Department of Epidemiology & Biostatistics, CUNY Graduate School of Public Health and Health Policy, City University of New York, New York, NY, USA
Albendazole treatment for neurocysticercosis (NC) resolves all active cysts in only 31% of patients. Host immune response appears to vary by patient characteristics, including sex and age, and it impacts parasite lifespan, but whether it modifies the impact of albendazole treatment is unclear. We used data on 99 participants of a randomized controlled trial (RCT) of albendazole treatment for NC to investigate if the effect of albendazole treatment on active cysts was modified by patient sex, age and pretreatment immunological lab measures (white blood cell, basophil, lymphocyte, eosinophil and monocyte counts). We used log-binomial models to look at resolution of all active cysts and linear regression to look at change in the number of active cysts by one month post treatment, adding interaction terms between treatment and each hypothesized effect modifier. We also ran stratified models to look at the direction of effect modification. We found that the impact of albendazole in resolving all active cysts was higher among males than females (RR=12.19 versus 2.74), younger than older patients (RR=8.69 versus 4.32), those with lower basophile count (RR=8.36 versus RR=1.5) and lower eosinophil count (RR=7.27 versus RR=3.82), but none of the interaction terms were statistically significant. When looking at change in the number of active cysts, the interaction between treatment and eosinophil count was significant and there was a reduction in the number of active cysts associated with treatment among those with low eosinophil counts but not those with high counts (β=-4.69 versus β=0.38). The impact of albendazole on NC parasites appears to be stronger among those with a weaker immune response, although most of the associations were not statistically significant, perhaps due to low power given the small sample size. Understanding how the host-immune system impacts the effectiveness of albendazole is key to developing improved treatment.