Risk Factors of Microbial Keratitis in Uganda: A Case Control Study

Simon Arunga,Guyguy M Kintoki,Stephen Gichuhi,John Onyango,Bosco Ayebazibwe,Rob Newton,Astrid Leck,David Macleod,Victor H Hu,Matthew J Burton

doi:10.1080/09286586.2019.1682619

Abstract

ABSTRACTPurpose: Microbial keratitis (MK), is a frequent cause of sight loss worldwide, particularly in low and middle-income countries. This study aimed to investigate the risk factors of MK in Uganda.Methods: Using a nested case control, we recruited healthy community controls for patients presenting with MK at the two main eye units in Southern Uganda between December 2016 and March 2018. Controls were individually matched for age, gender and village of the cases on a 1:1 ratio. We collected information on demographics, occupation, HIV and Diabetes Mellitus status. In STATA version 14.1, multivariable conditional logistic regression was used to generate odds ratios for risk factors of MK and a likelihood ratio test used to assess statistical significance of associations.Results: Two hundred and fifteen case-control pairs were enrolled. The HIV positive patients among the cases was 9% versus 1% among the controls, p = .0003. Diabetes 7% among the cases versus 1.4% among the controls, p = .012. Eye trauma was 29% versus 0% among the cases and controls. In the multivariable model adjusted for age, sex and village, HIV (OR 83.5, 95%CI 2.01–3456, p = .020), Diabetes (OR 9.38, 95% CI 1.48–59.3, p = .017) and a farming occupation (OR 2.60, 95%CI 1.21–5.57, p = .014) were associated with MK. Compared to a low socio-economic status, a middle status was less likely to be associated with MK (OR 0.29, 95%CI 0.09–0.89, p < .0001).Conclusion: MK was associated with HIV, Diabetes, being poor and farming as the main occupation. More studies are needed to explore how these factors predispose to MK.

Highlights

Microbial keratitis (MK), or infection of the cornea, can be caused by a range of pathogens
MK in low and middle-income countries (LMIC) has been described as a “silent epidemic”, which leads to substantial morbidity, related to blindness and other consequences such as pain and stigma.[2]
The cases without controls were dropped from the matched risk factor analysis

Summary

Introduction

Microbial keratitis (MK), or infection of the cornea, can be caused by a range of pathogens. The causative organisms include bacteria, viruses, protozoa (e.g. acanthamoeba), and fungi (yeasts, moulds and microsporidia). It is characterised by acute or sub-acute onset of pain, conjunctival hyperemia and corneal ulceration with a stromal inflammatory cell infiltrate. MK in low and middle-income countries (LMIC) has been described as a “silent epidemic”, which leads to substantial morbidity, related to blindness and other consequences such as pain and stigma.[2] It is the leading cause of unilateral blindness after cataract in Tropical regions and is responsible for about 2 million cases of monocular blindness per year.[3] The World Health

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