Occurrence of cryptococcal antigenaemia among HIV- uninfected patients with stroke in Nigeria: a pilot case-control study


Background: Infections have been associated with stroke occasionally, but are not considered to be a direct cause. We aimed to compare the prevalence of cryptococcal antigenaemia in stroke patients compared to stroke-free controls.

Methods: Through the Stroke Investigative Research and Education Network (SIREN) project, adults (aged >18 years) with stroke confirmed by computed tomography (CT) scan or magnetic resonance imaging (MRI) (cases) and age-matched and gender-matched stroke-free controls were recruited from the communities in catchment areas of the cases. A simple random sampling was used to select blood samples of stroke patients and controls in a 1:1 ratio. Serum cryptococcal antigen (CrAg) tests were performed using CrAg Lateral Flow Assays (BIOSYNEXR Crypto PS).

Results: Of the 100 HIV-uninfected patients (50 cases and 50 controls), majority 70 (70%) were males with a median age of 57 (range: 33-86) years. Thirty-six (72%) cases and 23 (46%) controls were hypertensive (p<0.001), while 6 (12%) cases and 14 (28%) controls were diabetic (p=0.059). Overall, CrAg was positive in 16% (n=16) of the participants; 10 (20%) among cases and 6 (12%) among controls (Odds ratio: 1.83; 95% confidence interval: 0.61-5.5; p=0.275). Overall, 13 deaths occurred, all among cases; death rates were similar between CrAg positive (2/10, 20%) and CrAg negative (11/40, 27.5%) stroke patients (p=0.628). Diabetes mellitus had a trend towards predicting a positive CrAg among cases (Odds ratios, 1.52 (95% CI: 0.97-2.4); p=0.069).

Conclusions: Cryptococcal antigenaemia appears to be more common in stroke patients compared to controls. Adequately powered studies are required to explore this observation.

Keywords: Fungal infections, Cryptococcal antigenaemia, Stroke, Diabetes, Nigeria.

Contexte: Des infections ont été associées à des accidents vasculaires cérébraux occasionnellement, mais ne sont pas considérées comme une cause directe. Nous visions à comparer la prévalence de l’antigénémie cryptococcique chez les patients victimes d’un AVC par rapport aux témoins sans AVC.

Méthodes: Dans le cadre du projet Stroke Investigative Research and Education Network (SIREN), des adultes (âgés de 18 ans ou plus) avec un AVC confirmé par tomodensitométrie (TDM) ou imagerie par résonance magnétique (IRM) (cas) et appariés selon l’âge et le sexe Des témoins sans AVC ont été recrutés dans les communautés des zones de desserte des cas. Un simple échantillonnage aléatoire a été utilisé pour sélectionner des échantillons sanguins de patients et de témoins d’AVC dans un rapport 1: 1. Des tests d’antigène cryptococcique sérique (CrAg) ont été réalisés à l’aide de tests CrAg à flux latéral (BIOSYNEXR Crypto PS).

Résultats: Sur les 100 patients non infectés par le VIH (50 cas et 50 témoins), la majorité 70 (70%) étaient des hommes avec un âge médian de 57 ans (intervalle: 33-86). Trente-six (72%) cas et 23 (46%) témoins étaient hypertendus (p <0,001), tandis que 6 (12%) cas et 14 (28%) témoins étaient diabétiques (p = 0,059). Dans l’ensemble, la CrAg était positive chez 16% (n = 16) des participants; 10 (20%) parmi les cas et 6 (12%) parmi les témoins (rapport de cotes: 1,83; intervalle de confiance à 95%: 0,61-5,5; p = 0,275). Dans l’ensemble, 13 décès sont survenus, tous parmi les cas; les taux de mortalité étaient similaires entre les patients ayant subi un AVC CrAg positif (2/10, 20%) et CrAg négatif (11/40, 27,5%) (p = 0,628). Le diabète sucré avait tendance à prédire un CrAg positif parmi les cas (odds ratios, 1,52 (IC à 95%: 0,97-2,4); p = 0,069).

Conclusions: L’antigénémie cryptococcique semble être plus fréquente chez les patients victimes d’un AVC que chez les témoins. Des études suffisamment puissantes sont nécessaires pour explorer cette observation.

Mots clés: Infections fongiques, antigénémie cryptococcique, accident vasculaire cérébral, diabète, Nigéria.

Correspondence: Dr. S. A. Fayemiwo, Department of Medical Microbiology and Parasitology, College of Medicine, University of Ibadan, Ibadan, Nigeria. E-mail address: dayteet@yahoo.co



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