Demographic Factors Associated with Presenting for Eye Evaluation in the Partnership for Research on Vaccines and Infectious Diseases in Liberia III Natural History Study of Ebola Virus Disease

Abstract:

PURPOSE:

Survivors of Ebola virus disease (EVD) are at risk for ocular complications after infection. We sought to identify demographic factors associated with the likelihood to present for eye examination among Ebola survivors enrolled in a longitudinal natural history study of EVD.

METHODS:

The Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III Ebola natural history study is a 5-year study that seeks to identify long-term sequelae of EVD, including ocular sequelae. All survivors enrolled in the PREVAIL parent study from June 2015 to March 2016 were asked to return for comprehensive eye examination through June 2016. Logistic regression was conducted using self-reported survivor status, age, gender, and distance from the hospital as covariates.

RESULTS:

A total of 1448 subjects enrolled in the parent PREVAIL III longitudinal cohort during the defined window, of which 1375 (95.0%) followed up for baseline eye examination. Ebola survivors (635/661, 96.1%) and adult close contacts (727/767, 94.8%) demonstrated a comparable likelihood for presenting for eye examination (odds ratio [OR] 0.68, 95% confidence interval [CI] 0.36–1.28). In an adjusted model, age over 50 (OR 10.2, 95% CI 1.35–77.3) and living outside Montserrado County (OR 0.18, 95% CI 0.10–0.33) were associated with the likelihood of presenting for a baseline comprehensive eye examination.

CONCLUSION:

Most EVD survivors and their close contacts who enrolled during the study window presented for eye examinations. Older participants and those who lived closer to clinical facilities were most likely to present. Focused strategies accounting for these factors may assist with organizations planning survivor care in the setting of EVD.

Introduction

The West Africa outbreak of Ebola virus disease (EVD) was the largest Ebola outbreak in history, resulting in 28,616 total cases and 11,310 deaths.[1,2] Survivors of EVD experience social isolation and physical morbidity: stigma, unemployment, and postebola syndrome including joint pain, neurocognitive deficits, depression, and ocular problems.[3,4,5] Data are needed to inform outreach efforts to address the needs of survivors.

In response to the clinical needs of survivors, multiple initiatives have been established in Ebola-affected countries to provide clinical care through government and nongovernmental organizations. Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III is a 5-year observational cohort study conducted by the PREVAIL, a clinical research partnership between the Liberian Ministry of Health and Social Welfare and the National Institutes of Health of the United States of America. It is the largest study of EVD and its long-term effects and includes an ophthalmology sub-study. All Ebola survivors and their close contacts enrolled in PREVAIL III at JFK Medical Center during the window of this study were asked to return for comprehensive eye examination, including imaging and dilated fundus examination with an ophthalmologist. In this study, we assess what factors affected the likelihood that participants in the parent PREVAIL III study presented for baseline ophthalmic evaluation.

Methods

Participants

Inclusion criteria for the PREVAIL III longitudinal eye study included enrollment in the PREVAIL III (P3) parent study from June 2015 to March 31, 2016, and receiving a baseline eye examination by June 30, 2016. Self-reported survivors with documentation of infection or hospitalization were invited to participate along with close contacts. After the initial clinical visit, which included blood draw for routine laboratory studies, Ebola antibody levels, and general physical examination, participants were invited to return for counseling and eye examination. Both EVD survivors and close contacts from the main site at John F. Kennedy Hospital in Monrovia, Montserrado County, Liberia, were eligible for longitudinal eye sub-study enrollment. For all participants, both the initial visit and eye examination were conducted free of charge. Travel allowance and a meal were provided.

Statistical analysis

All self-reported survivors who enrolled during the time period were invited to receive ophthalmic evaluation regardless of whether antibodies to Ebola virus would subsequently be identified. Therefore, classification as a survivor for this analysis is based on self-report rather than serology, which is used in PREVAIL III to confirm the status of survivors and controls,[6] with slightly smaller groups.

Logistic regression was performed using SAS software (version 9.4, SAS Institute, Inc., Cary, NC, USA) with variables: age, gender, group classification (survivor, contact, or birth cohort), time of year (to determine the effect of rainy season), and location of residence used as covariates. Odds ratios (ORs) described in the results have been adjusted for these variables. P <0.05 was considered statistically significant.

Results

A total of 1448 participants enrolled in the longitudinal eye sub-study, including 661 survivors, 767 close contacts, and 20 infant close contacts. Overall, a high proportion of participants followed up for eye examination (n = 1375, 95%). Factors associated with follow-up are included in Table 1. Follow-up was high among both survivors (n = 635, 96%) and close contacts (n = 727, 94.8%), but less among the birth cohort (n = 13, 65.0%). The OR of presentation among contacts relative to survivors suggests no difference between these two groups (OR 0.68, 95% confidence interval [CI] 0.36–1.28).

Table 1.

Predictors of attending baseline eye exam by June 30, 2016 among

Prevail-3 participants enrolled at JFK through March 31, 2016[1]
	Participants	Attended exam, n (%)	Unadjusted*		Adjusted*
			OR	95% CI	OR	95% CI
Overall	1448	1375 (95)
Group	1448
Survivor	661	635 (96.1)	Reference		Reference
Close contact	767	727 (94.8)	0.74	0.45–1.23	0.68	0.36–1.28
Infants <1 year old	20	13 (65)	0.08	0.03–0.21	0.08	0.02–0.26
P			<0.001		<0.001
Age	1448
<18	426	390 (91.5)	Reference		Reference
18–50	889	853 (96)	2.19	1.36–3.52	1.6	0.93–2.75
>50	133	132 (99.2)	12.2	1.65–89.7	10.2	1.35–77.3
P			<0.001		0.03
Gender	1448
Male	642	614 (95.6)	Reference		Reference
Female	806	761 (94.4)	0.77	0.48–1.25	0.72	0.44–1.19
P			0.29		0.21
Enrolment month	1448
June, 2015–October, 2015	792	762 (96.2)	Reference		Reference
November, 2015–March, 2016	656	613 (93.4)	0.56	0.35–0.91	1.01	0.54–1.91
P			0.02		0.97
Montserrado county	1448
Montserrado	1342	1286 (95.8)	Reference		Reference
Outside Montserrado	106	89 (84)	0.23	0.13–0.41	0.18	0.10–0.33
P			<0.001		<0.001

JFK: John F. Kennedy, OR: Odds ratio, CI: Confidence interval

Odds of presentation were comparable between women and men (OR 0.72, 95% CI 0.44–1.19). However, compared to participants <18 years of age (390/426, 91%), the odds of follow-up among those over 50 years of age were significantly higher (OR 10.2, 95% CI 1.35–77.3). Notably, 132 of 133 (99.2%) survivors in this latter category presented for examination.

After adjustment, the odds of presentation between the rainy season (June to October) and dry season (November to March) were comparable (OR 1.01, 95% CI 0.54–1.91).

The bottom of Table 1 highlights the impact of geographical distance comparing participants within Montserrado County (Greater Monrovia, Liberia) and those in counties outside Montserrado. While a large proportion of participants who lived both within (1286/1342, 95.8%) and outside (89/106, 84.0%) Montserrado County presented for follow-up, the higher rate among participants more proximal to the examination facility was significant after adjusting for other factors (OR 0.18, 0.10–0.33).

Discussion

This study explored factors associated with presenting for eye examinations in the setting of an emerging infectious disease. Although access to eye care is an essential approach to combating global blindness, multiple factors have been shown to impede access to eye care including age and educational level,[7] gender,[8] awareness and attitudes to eye care,[8] transportation,[9] direct and indirect cost of eye care,[9,10,11] and severity of vision loss.

In this study, a large proportion of participants presented for eye examinations. Age and geographical location of residence were significantly associated with odds of follow-up, while gender was not a significant contributor to participation rates. Infants born to Ebola survivors were significantly less likely to present for eye examination, which highlights the need for education regarding preventative eye examinations after birth in this cohort, and dedicated efforts to facilitate access. High rates of presentation have been important for optimizing the quality of comparison of survivors and close contacts,[12] and especially for follow-up after surgery in this cohort, which is time-sensitive.[13]

The high attendance rate of survivors and contacts highlights the close involvement of trackers as part of social mobilization. Social mobilization facilitates exposure to a wide sector of the community through mass media public health awareness messages, meetings with EVD survivors and close contacts, discussions with community leaders, radio promotional messages, flyers, and radio talk shows interpreted in 16 tribal vernacular languages across Liberia. Our eye clinic provided a reminder phone call 1 day before each participant’s clinical visit.

The effect of age on presentation may be multifactorial. Younger participants depend on guardians for transportation, and in our interactions with younger participants, some have cited school conflicts as a cause for failure to follow up. We were encouraged by almost complete participation among the oldest participants, as numerous comorbidities are associated with age. Our study showed similar rates of presentation among men and women, suggesting that efforts to ensure access were equally effective across genders.

Given that mobility in Liberia is affected by the rainy season, we analyzed seasonal variation. After adjustment, no significant difference was found in the odds of follow-up across times of year.

Conclusion

In summary, in this large study of Ebola survivors and their close contacts, both groups presented at high rates for comprehensive eye examination. Higher age and shorter distance from the examination site were associated with an increased likelihood of presentation. Further study may assist to identify additional factors affecting presentation.

Financial support and sponsorship

This research was supported by the National Institutes of Health, United States, and the Ministry of Health of Liberia. Allen Eghrari was supported by NIH Grant L30 EY024746.

Conflicts of interest

There are no conflicts of interest.