The ongoing coronavirus disease 2019 (COVID‐19) pandemic requires significant mitigation efforts including large‐scale testing programmes to detect new cases and to keep infection rates under control. Despite the presence of asymptomatic transmission, passive and random testing of unselected asymptomatic individuals may be inefficient. 1 In contrast, sentinel surveillance, whereby a pre‐selected set of healthcare facilities routinely conducts testing of a defined patient population, may offer a way to efficiently measure infection rates to allow the prevalence in the community at large to be estimated, as well as to predict outbreaks. 1 Sentinel surveillance of those at high risk for infection, transmission or complications, such as the elderly or hospital patients, may support infection control efforts. 2
Elective surgeries present a risk of nosocomial severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) transmission amongst patients and healthcare workers, warranting screening of incoming surgical patients—particularly amongst high‐risk elderly patients undergoing common elective surgeries such as orthopaedic or ophthalmic procedures. Therefore, we propose cataract surgery patients as good sentinel surveillance candidates because: (a) they may have higher susceptibility to SARS‐CoV‐2 infection 3 as well as complications from COVID‐19 due to their older age and high rates of comorbidities 4 ; (b) cataract surgery is one of the most common elective surgical procedures worldwide, permitting monitoring of a large and representative high‐risk population; and (c) the ophthalmic setting is a potentially a high‐risk environment as phacoemulsification has been shown to generate aerosols. 5
We investigated data from two epidemiological studies conducted in Australia to understand whether people undergoing cataract surgery might have a greater burden of risk factors that portend worse COVID‐19 outcomes and thus may constitute an appropriate sentinel population. We used multivariable logistic regression to compare the rates of known risk factors for COVID‐19 complications between participants in the National Eye Health Survey (NEHS, 2015‐2016) who had undergone cataract surgery and those who had not undergone cataract surgery within the year preceding the survey. Similar comparisons were made for participants in the Melbourne Collaborative Cohort Study (MCCS) who reported diagnosis with cataract within the year preceding follow‐up study wave 1 (1995‐2002) and those who had not.
In total, 4806 NEHS participants (aged 40‐98 years) were included. Of these, 167 (3.5%) reported having undergone cataract surgery within the past year and were more likely than those who had not to have diabetes (odds ratio [OR]: 1.66, 95% confidence interval [CI]: 1.16‐2.38 adjusted for age and Indigenous status), a history of stroke (adjusted OR: 1.74, 95% CI: 1.06‐2.85) and to be ≥65 years old (adjusted OR: 4.91, 95% CI: 3.32‐7.27) (Table 1).
TABLE 1.
Comparison of risk factors for severe COVID‐19 disease between NEHS participants who reported having cataract surgery within the previous year vs those who did not, and between Melbourne Collaborative Cohort Study participants who reported receiving a cataract diagnosis within the previous year vs those who did not
| NEHS self‐reported cataract surgery in last year | ||||
|---|---|---|---|---|
| No (n = 4639) | Yes (n = 167) | OR a (95% CI) | P‐value | |
| Age ≥ 65 years, n (%) | 1869 (40.3%) | 130 (77.8%) | 4.91 (3.32‐7.27) | <.001 |
| Male sex, n (%) | 2053 (44.3%) | 84 (50.3%) | 1.22 (0.90‐1.67) | .204 |
| Self‐reported diabetes, n (%) | 1021 (22.0%) | 50 (29.9%) | 1.66 (1.16‐2.38) | .006 |
| Self‐reported stroke, n (%) | 288 (6.2%) | 20 (12.0%) | 1.74 (1.06‐2.85) | .029 |
| Cataract diagnosis in last year | ||||
|---|---|---|---|---|
| No (n = 30 236) | Yes (n = 719) | OR b (95% CI) | P‐value | |
| Age ≥ 65 years, n (%) | 9260 (30.6%) | 521 (72.5%) | 5.96 (5.05‐7.03) | <.001 |
| Male, n (%) | 12 579 (41.6%) | 216 (30.0%) | 0.54 (0.46‐0.64) | <.001 |
| Self‐reported asthma, n (%) | 3420 (11.3%) | 100 (13.9%) | 1.28 (1.03‐1.59) | .026 |
| Self‐reported liver disease, n (%) | 609 (2.0%) | 11 (1.5%) | 0.77 (0.42‐1.41) | .402 |
| Self‐reported hypertension, n (%) | 7290 (24.1%) | 272 (37.8%) | 1.38 (1.18‐1.61) | <.001 |
| Self‐reported diabetes, n (%) | 1264 (4.2%) | 72 (10.0%) | 1.91 (1.48‐2.46) | <.001 |
| Self‐reported history of cancer, n (%) | 2706 (8.9%) | 88 (12.2%) | 1.08 (0.86‐1.36) | .503 |
| Self‐reported history of stroke, n (%) | 454 (1.5%) | 21 (2.9%) | 1.19 (0.76‐1.86) | .450 |
| Body mass index ≥ 30, n (%) | 5350 (17.7%) | 142 (19.7%) | 1.17 (0.97‐1.41) | .101 |
| Self‐reported heart disease, n (%) | 2084 (6.9%) | 88 (12.2%) | 1.13 (0.89‐1.42) | .315 |
Abbreviations: CI, confidence interval; COVID‐19, coronavirus disease 2019; NEHS, National Eye Health Survey; OR, odds ratio.
Estimated via multivariable logistic regression adjusting for age and Indigenous status.
Estimated via multivariable logistic regression adjusting for age.
Of the 30 236 MCCS participants (aged 40‐80 years), 719 (2.4%) reported a cataract diagnosis within the previous year. Compared to those reporting no cataract diagnosis, they had higher odds of reporting a history of asthma (age adjusted OR: 1.28, 95% CI: 1.03‐1.59), hypertension (adjusted OR: 1.38, 95% CI: 1.18‐1.61) and diabetes (adjusted OR: 1.91, 95% CI: 1.48‐2.46), and of being ≥65 years old (OR: 5.96, 95% CI: 5.05‐7.03) but not of having liver disease, cancer, stroke, obesity or heart disease (Table 1).
One limitation of this study is that self‐report for cataract diagnosis and comorbidities may have underestimated their true prevalence, thereby attenuating estimates of association. Furthermore, these findings are based on Australian data, and although similar associations have been reported in other high‐income countries, their relevance to countries requires consideration of local contexts. Nonetheless, these findings indicate that people undergoing cataract surgery are a group with risk factors for transmission, infection, complications and death from COVID‐19. Sentinel surveillance of this high‐risk group using preoperative screening questionnaires and perioperative testing may yield dual benefits of protecting patients and healthcare workers whilst supporting infection control amongst a high‐risk segment of the population.
FINANCIAL DISCLOSURE
CERA receives Operational Infrastructure Support from the Victorian Government.
CONFLICT OF INTEREST
None declared.
ETHICS STATEMENT
Ethics approval for the NEHS was granted by the Royal Victorian Eye and Ear Hospital Human Research Ethics Committee. Ethics approval for MCCS was granted by the Human Research Ethics Committee of the Cancer Council Victoria.
ACKNOWLEDGEMENTS
The authors are grateful to the Principal Investigator of the NEHS, Associate Professor Mohamed Dirani, for contributions to this letter and for use of NEHS data and to the current Principal Investigator of the MCCS, Dr Allison Hodge, and the Cancer Council Victoria for kindly providing data from the MCCS.
Funding information Australian Government Department of Health; Novartis Australia; Peggy and Leslie Cranbourne Foundation; VicHealth; Cancer Council Victoria; National Health & Medical Research Council of Australia (NHMRC), Grant/Award Numbers: Program Grant 209057, Capacity Building Grant 251533, Enabling Grant 396414
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