ABSTRACT
As of 2018, cryptococcal antigen (CrAg) screening in patients with advanced human immunodeficiency virus (HIV) disease (AHD) was not routinely implemented in Nigeria despite being recommended in the national HIV treatment guidelines. Our aim was to determine the prevalence and risk factors for asymptomatic cryptococcal antigenemia in adult people living with HIV (PLHIV) in Nigeria to advocate for the implementation of routine CrAg screening. A descriptive cross-sectional study and CrAg screening of consecutive adult PLHIV with CD4 counts ≤200 cells/µL was conducted from April 2018 to April 2019 at HIV clinics in eleven tertiary hospitals spread across Nigeria's six geopolitical regions. Prevalence of asymptomatic cryptococcal antigenemia was estimated by facility and geopolitical zone. Logistic regression was conducted to identify risk factors for cryptococcal antigenemia. In total, 1,114 patients with AHD were screened. The overall prevalence of asymptomatic cryptococcal antigenemia was 3.9% with wide variation across facilities (range: 0/75 [0%]- 15/122 [12.3%]) and geopolitical zones (range: 0/75 [0%]-19/279 [6.8%]). Prevalence of antigenemia was highest in the South-West (19/279 [6.8%]) and lowest in the North-East (0/75 [0%]). Prevalence was 5.2% (26/512) and 3.2% (18/561) in patients with CD4<100 and CD4 of 101-200, respectively. Of all patients with antigenemia, 50% were on antiretroviral therapy (ART) at the time of having a positive CrAg test. In adjusted analysis, cryptococcal antigenemia was significantly less in patients on ART and patients who had completed any formal education. The survey showed a high overall burden of cryptococcal antigenemia in Nigeria, with variable prevalence across geopolitical regions. We provided valuable evidence for implementing routine CrAg screening of AHD patients in Nigeria which has commenced in selected centres.
ABSTRACT
BACKGROUND AND OBJECTIVES: Commercial Aspergillus IgG antibody assays have become pivotal in the current diagnosis of chronic pulmonary aspergillosis (CPA). However, diagnostic cutoffs have been found to vary from manufactures' recommendations in different settings. This study aimed to establish the Aspergillus IgG reference range among Nigerians and determine a diagnostic cutoff for CPA. METHODS: Sera from 519 prospectively recruited healthy blood donors and 39 previously confirmed cases of CPA were analysed for Aspergillus IgG levels using the Bordier test kit (Bordier Affinity Products SA, Crissier, Switzerland). Accuracy versus cutoff profile and receiver operating characteristics (ROC) curve were analysed for both CPA cases and controls using the R-Studio (2020), (Window desktop, version 4.0.2 software with R packages "nnet" and "ROCR"). RESULTS: Among healthy blood donors, 141 (27.2%) were aged 16-25 years with median (interquartile range, IQR) of 22 (20-24) years; 304 (58.6%) were aged 26-40 years with median (IQR) of 32 (29-36) years; while 74 (14.2%) were aged 41-60 years with median (IQR) of 46 (44-49.75). Median IgG level in respective age groups were 0.069 (0.009-0.181), 0.044 (0.014-0.202) and 0.056 (0.01-0.265) with no significant difference found in the three age categories (p = 0.69). The overall diagnostic cutoff for the diagnosis of CPA was 0.821 with an accuracy of 97.1% and area under the curve (AUC) = 0.986. CONCLUSION: The optimal diagnostic cutoff for diagnosing CPA in Nigerians using the Bordier kit was 0.821 which is lower than the manufacturer's recommended cutoff of 1.0. The determination of this cutoff among Nigerians will significantly enhance accurate identification of CPA and assessment of its true burden in Nigeria.
