key: cord-0811753-9s1hjoo8
authors: Loza, Andrew J.; Doolittle, Benjamin R.
title: The Effect of COVID-19 Pandemic Restrictions on Lead Screening in a Primary Care Clinic
date: 2021-05-21
journal: J Pediatr Health Care
DOI: 10.1016/j.pedhc.2021.03.004
sha: 0cc2fdb23591e564ecfa0b859234be32dffae3a5
doc_id: 811753
cord_uid: 9s1hjoo8

INTRODUCTION: COVID-19 has disrupted outpatient pediatrics, postponing well child care to address immediate patient-safety concerns. Screening for lead toxicity is a critical component of this care. Furthermore, children may be at increased risk for lead exposure at home due to social restrictions. We present data on how COVID-19 restrictions have impacted lead screening in a primary care practice. METHOD: Lead testing data on 658 children in an outpatient primary care practice in Connecticut were analyzed to determine the effect of COVID-19 restrictions on lead screening rates, levels, and deficiencies. RESULTS: Lead screening significantly decreased during peak restrictions, leading to increased screening deficiencies. Despite this decreased volume, screening lead levels increased during peak restrictions. DISCUSSION: These data show how COVID-19 restrictions have disrupted routine care and highlight the importance of continued lead screening in at-risk populations. The EMR can be leveraged to identify deficiencies to be targeted by Quality Improvement initiatives.

COVID-19 has dramatically impacted outpatient pediatrics (Chanchlani, Buchanan, & Gill, 2020; Pediatrics, 2020) . Well Child Care (WCC) and sub-critical follow-up visits have been canceled or postponed for patient safety reasons, however, the age-appropriate WCC performed at these visits is critical for long term health outcomes (Hagan, Shaw, & Duncan, 2007; Melnyk et al., 2012) . Missed or delayed routine childhood vaccinations due to COIV-19 have received significant attention (Santoli, 2020; Saxena, Skirrow, & Bedford, 2020) , but an additional critical component of well child care is screening for lead exposure in at risk individuals(C. o. E. Health, 2016) .

Lead is a potent toxin with neurological, cardiac, gastroenterologic, hematologic, and other effects (Flora, Gupta, & Tiwari, 2012) . Recent statements from the Centers for Disease Control (CDC) and National Toxicology Program (NTP) highlight that while the severity of toxicity is dose dependent, even lead levels below the standard cutoff of 5 μg/dL can lead to behavior problems and impaired cognitive function (Control & Prevention, 2012; Lanphear, 2015; Lanphear et al., 2005) . To combat this, many states have passed legislation mandating testing that focuses on screening children. In Connecticut annual screening is mandatory from 9 months to 3 years of life and advised at provider discretion until 6 years of life (C. D. o. P. Health, 2013) .

Pediatric exposure to lead primarily comes from environmental sources. Major contributors are lead paint, drinking water, contaminated dust, and contaminated soil. Risk of exposure from these sources is linked to the age and setting of housing with higher risk for older housing in urban settings (Mielke & Reagan, 1998; O'Connor et al., 2018) . Federal legislation banned lead in residential paint and in the pipes and solder used for drinking water in 1978 and 1986 respectively, (Levin et al., 2008; O'Connor et al., 2018) though older houses may pose a risk if mitigation efforts have not been performed. Lead in soil arises from pulverized paint as well as deposition of lead compounds from industrial facilities and exhaust from combustion of leaded gasoline (Clarke, Jenerette, & Bain, 2015; Mielke & Reagan, 1998; O'Connor et al., 2018) .

Contaminated soil surrounding houses can then be tracked indoors and contribute to lead dust.

Collectively, older housing stock in areas of high vehicle traffic, as is often found in urban areas, is associated with increased risk of exposure (Levin et al., 2008) . Exposure to lead in the home environment raises unique concern in light of social changes introduced by restrictions during the COVID-19 pandemic. Quarantines and virtual schooling may have increased time spent at home where these exposures are most likely to occur.

We sought to quantify the degree to which COVID-19 restrictions impacted routing lead testing and determine if changes to social settings contributed to a change in lead exposure. In this paper, we provide an Electronic Medical Record (EMR) based retrospective analysis of lead screening data from a primary care practice in a resident clinic. We analyzed the volume of lead screening tests as well as ages of children screened during the COVID-19 pandemic as compared to matched control time periods. We also examined screening lead levels to assess for evidence of changes in exposure. Lastly, we quantify how this change in lead screening has affected the number of children with deficiencies based on state and national guidelines.

This study was performed at a community-hospital-based resident primary care clinic in Connecticut. Patients are seen by both attending physicians and resident physicians with an attending physician precepting. Point of Care (POC) lead screening is performed in office, and venous testing for confirmation or follow-up is available in-office or on the same campus.

Corporation, Verona, WI). Data were extracted using the Reporting Workbench which allows users to create queries to compile data on patients within their practice based on defined criteria.

Lead testing data was obtained for all patients between 9 months and 6 years of age during the time period of January 1, 2019 to December 1, 2020. This allowed seasonal-matched comparison of testing during periods of COVID-19 restrictions to control for potential seasonal variations in lead levels or testing volume. Custom reports were created in the Epic Reporting Workbench which provided data on all children meeting the age criterion and lead testing performed during this time period.

This study was approved as a quality improvement project by [ name removed for manuscript review ], the sponsoring agency of the practice.

Each lead test was annotated by method and class. Testing methods were POC or venous testing.

Testing class refers to whether the test was used for screening, confirmation of an elevated screen, or follow-up of a known elevated venous level. Screening denotes a POC lead test with either no prior test or a normal prior test. Confirmation denotes a venous lead test following a screening test with a value ≥5 μg/dL. Follow-up denotes a venous lead test following a test with a venous lead level ≥5 μg/dL.

Deficiencies in testing were determined based on Connecticut state law and CDC recommendations. In Connecticut, annual screening is mandated between 9 months and 35 months of age. A screening deficiency was considered to be any screen performed at ≥ 13 months of age or ≥13 months from the prior screen or last venous lead sample with a value ≤5 μg/dL.

Time periods for analysis of the effect of COVID on lead screening were defined based on ordinances passed within Connecticut that limited activity. January 1 st through March 20 th was considered Pre-restrictions. On March 20 th , 2020 strict stay at home orders were passed and persisted until to June 6 th , 2020; this time period was labeled as Peak restrictions. The time period from June 6 th , 2020 to December 1 st , 2020 was used to mark the period with ongoing effects but fewer mandated restrictions; labeled as Relaxed restrictions. Due to potential seasonal variations in well child visit volume and known variation in lead levels (Yiin, Rhoads, & Lioy, 2000) , these same time periods from 2019 were used as controls.

To assess differences in test quantity, observations were binned by time period and statistical tests were performed between matched periods from 2019 and 2020. Statistical differences in counts were examined using the Rate Ratio test. Age difference in these bins was assessed using the non-parametric Mann Whitney U test due to non-normal distribution of data. Lead screening test values were discretized into 5 μg/dL ordinal bins for statistical comparison using the asymptotic linear-by-linear association test. This was due to the fact that the majority of screening test values fell below the limit of detection which limited the use of statistical tests which require continuous variables. Venous lead sample values for confirmatory tests were analyzed with the same discretized method. The number of outstanding confirmatory tests between time periods was assessed using the Fisher Exact test. Time period assignment confirmatory tests was based on the associated screening test date. Differences in testing deficiency prevalence between matched time-periods was assessed using two-sample proportional test. Differences in the rate of incidence for new or resolved deficiencies was assed using the Rate Ratio test. Statistical testing was performed in R (R Core Team, 2013).

During the study period, 658 children from 9 months to 6 years of age were evaluated in clinic, and a total of 1261 lead tests were performed on 561 unique children. Tests were classified as screening, confirmation, or follow-up as defined in Methods. Demographic data and testing type distribution are summarized in Table 1 .

To determine the effect of the COVID-19 pandemic on lead screening, time periods with differential social restriction mandates were created. January 1 st to March 19 th was defined as Pre restriction, March 20 th to June 6 th was defined as Peak restriction, and June 6 th to December 1 st was defined as Relaxed restrictions based on executive orders limiting activity. These intervals in 2020 were compared to the equivalent time periods during 2019 to control for seasonal variations in lead testing levels and quantity (Yiin et al., 2000) . Monthly screening test volume was reduced during Peak restriction to approximately half of the prior year value (RR = 0.48, p= 0.0002) but not during the pre or relaxed restriction time period (RR = 0.99, p-value 1.0 and RR = 1.03, p = 0.79 respectively) as shown in Figure 1 . We also observed a significant reduction in mean age at screening during Peak restriction (mean age 2.0 vs. 2.8 years, p = 0.002) but not during Pre or Relaxed restriction time periods as shown in Figure 2 . This indicated that while testing was preserved for youngest children, older children were screened less often during peak restriction.

During peak restrictions, normal daily activities of patients and families dramatically changed with school and daycare closures. This potentially led to more time spent at home where lead exposure is known to occur. We therefore examined screen lead levels to determine if there was evidence of increased exposure, Figure 3 . The frequency of tests with a lead value ≥5 μg/dL significantly increased during Peak restriction (p = 0.02). During the Relaxed restriction period there was a trend towards an increase, but this did not meet statistical significance (p = 0.1).

Blood lead levels from confirmatory tests for positive screens was analyzed by limited by the number of outstanding tests. We found no significant difference in the number of outstanding tests between time periods. With the caveat of significant numbers of outstanding tests, we did not observe significant differences in confirmatory samples with blood lead levels ≥5 μg/dL during any time period (Supplemental Figure 1) .

We additionally explored the effect of COVID-19 on meeting mandated screening requirements.

Definitions for deficiencies in each category are detailed in the Methods section. The proportion of children 9 months to 3 years of age with active screening deficiencies increased significantly during the COVID-19 pandemic, Figure 4 . The increase started, but was not significant, during Peak restrictions and became statistically significant during the Relaxed restriction period (0.46 vs 0.67, p < 0.0001). The total number of active deficiencies during a time period represents both new deficiencies that occurred during the time period and those carried over from a prior period without being resolved. To separate these scenarios, the rates of deficiency occurrence and resolution were compared between time periods. The rate of occurrence for new deficiencies during Peak restrictions neared significance (RR 1.87, p=0.07) and was significant during the Relaxed restrictions period (RR 2.27, p=0.0002). The rate of deficiency resolution actually increased during the Relaxed restrictions time period as well (RR 1.61, p = 0.04), representing a return to increased screening. Full Rate Ratios and significance levels are shown in Table 2 .

This study shows the effect of restrictions imposed during the COVID-19 pandemic on lead screening within a primary care clinic in an urban setting in Connecticut. We found that lead screening volume was dramatically reduced during the peak restrictions of the COVID-19

pandemic. This reduction primarily affected screening in older children as evidenced by a decrease in mean age of children being screened. This likely reflects prioritization of WCC visits from birth to 15 months old where the majority of critical vaccines are administered. Although screening volume has returned to baseline, the number of children not meeting screening recommendations has continued to increase, indicating that the backlog of missed tests is continuing to have an effect. We also find that even as screening volume has declined, the proportion of screening tests with elevated lead levels has increased. One mechanism of primary concern is whether the change in daily social structure that restriction put in place to address the spread of COVID-19 has created a potential for increased lead exposure. With fewer daycares and schools open, children from 9 months to 6 years of age may be spending more time at home. This may increase exposure in two related ways. First, increased time spent in an environment containing lead may directly increase exposure risk. Second, lead exposure is known to be seasonal and related to tracking of contaminated dust into the home (Yiin et al., 2000) . Changes to activities of older siblings and relatives during COVID-19 restrictions may have increased lead-contaminated dust loading. Furthermore, it is likely that home visits to identify lead exposure and subsequent mitigation efforts have also been affected by the same restrictions imposed by COVID-19 precautions.

There are weaknesses which may limit the generalizability of the findings. First, this study was conducted at a single site, so lead exposure risk as well as the magnitude and timeline of COVID-19 restrictions are specific to the study location. Second, this study was retrospective and used and EMR-based label of assigned Primary Care Physician (PCP) to determine patients that were included. Therefore, patients who transferred practices during this time period without a change to the PCP would appear as having testing deficiencies and any laboratory testing performed outside of the medical system would not appear. Third, due to smaller sample sizes, we are not able to confidently examine trends in confirmation or follow-up testing. Fourth, these data focus on screening tests and not data from confirmatory venous blood levels. Preliminary analyses (Supplemental Figure 1) show no significant difference in the venous blood levels for confirmatory tests during these time periods, however the number of positive screening tests is small and there are a significant number of outstanding confirmatory tests.

Despite these limitations, this study shows that COVID-19 has significantly delayed an important component of WCC during a time when social restrictions may have increased the amount of time in environments where exposure may occur or altered the exposure profile of these environments. We do not argue that patient safety should be compromised to maintain prepandemic lead screening but rather provide these data to increase awareness of the effect of pandemic related restrictions on WCC. The methodology employed serves as a model for how the EMR can be leveraged to direct panel management when the sequence of normal WCC is interrupted. Patients with deficiencies can easily be identified remotely and quality improvement structures can be created to resolve patients at highest risk.

Andrew Loza and Benjamin Doolittle are the only authors of the essay, which has not been previously published and is not under consideration at any other journal. This project received no external funding. We each contributed to the study design, data analysis, writing, and editing process. We have no conflicts of interest.

Dr. Loza and myself are the only authors of the essay, which has not been previously published and is not under consideration at any other journal. This project received no external funding. We each contributed to the study design, data analysis, writing, and editing process. We have no conflicts of interest. . Screening test lead levels by time period. POC screening values were discretized into ordinal categories, 0-5 μg/dL, 5-10 μg/dL, 10-15 μg/dL, and ≥15 μg/dL. The fraction of tests in each lead level category is shown for each COVID-19 restriction time period and year. There was no significant difference during the Pre time period (asymptotic linear-by-linear association test, p=0.61). During Peak restriction there was a significant increase the fraction of tests with higher lead levels (asymptotic linear-by-linear association test, p=0.03). During the relaxed restriction, a greater fraction of values were ≥5 μg/dL but this association was not significant (asymptotic linear-by-linear association test, p=0.17). 

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