SARS-CoV-2 pandemic effect on pediatric asthma health care utilization in an urban hospital

Abstract

Background

The “September epidemic” is a well-described phenomenon of increased pediatric asthma-related health care utilization from August to September each year. The coronavirus disease 2019 (COVID-19) pandemic has brought about significant changes in health care utilization, warranting an investigation into its impact on the September epidemic.

Objective

Our aim was to identify the impact of COVID-19 in asthma-related health care utilization, specifically in the September epidemic.

Methods

Our study involved a retrospective analysis of data from a Children's Hospital in New York City. We compared the change in asthma-related health care utilization during August and September 2020 with the average change in utilization during the same period in 2017-2019 and 2021-2022. Stratified analyses based on age and sex were conducted by using chi-square tests to determine variations in health care utilization.

Results

During September 2020, there was a marked reduction in emergency department (ED) visits related to asthma, with only a 6% rise from the preceding month. This stands in contrast to the observed increases from 89% to 193% in the other years studied (P < .05 for all). This pattern was seen in both sexes and in children under 13 years old (P < .05). No significant variation was found for those older than 13 years (P > .05).

Conclusions

Despite an overall reduction in health care utilization over the first year of the COVID-19 pandemic, the decline in ED visits related to asthma during the September epidemic was significantly more pronounced. These results suggest that there may be remediable risk factors contributing to the September epidemic that can be used to guide future interventions for managing pediatric asthma.

Introduction

The asthma September epidemic refers to the increase in asthma-related health care utilization, such as hospitalizations and emergency department (ED) visits, at the start of the academic school year.¹ In general, during the summer months, there is a decline in asthma-related health care utilization; however, this activity increases in September owing to higher prevalence of viral infections, associated with the congregation of children in connection with the return to school.² In certain parts of the country, the fall allergy season increases these changes.

During 2020, the response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus included lockdowns and school closures beginning in March 2020 and in some areas, continuing through 2021. During September 2020, many schools remained closed to in-person learning, and many extracurricular activities did not resume.³ In addition to this disruption, public health messaging urged social distancing and mask wearing to mitigate the spread of the virus. The combination of these measures largely meant that children were no longer congregating in September 2020. Although these measures were designed to decrease the spread of SARS-CoV-2, they also seemed to be effective against other viral infections that may be common triggers of asthma.⁴ For example, a significant decrease in pediatric influenza–related hospitalizations was observed during the 2020-2021 flu season as compared with in prior seasons.⁵

We hypothesized that during the height of the coronavirus disease 2019 (COVID-19) pandemic (2020-2021), the sharp increase in asthma-related ED visits and hospitalizations from August to September would be blunted. With fewer respiratory infections triggering asthma exacerbations owing to school closures, social distancing, and mask wearing, children would experience fewer ED visits and hospitalizations than observed during the typical September epidemic.

Results and discussion

We defined the “September epidemic” as the difference between the number of asthma visits from August to September. We averaged the September epidemic for the years 2017, 2018, and 2019 and used this average as our baseline. The September epidemic each subsequent year until 2022 was calculated and then individually compared to the 2017-2019 “baseline” by using a chi-square test. Stratified analyses based on age and sex were conducted using chi-square tests to determine variations in health care utilization.

Table I compares the number of ED encounters (all-cause and asthma-related) during the months of August and September from 2017 to 2022. Every year, there was an increase in all-cause ED encounters (from 7% to 23%), except in 2020, during which there was a 5% decrease. Similarly, every year, there was a much higher increase in asthma encounters (from 89% to 193%), except in 2020, during which there was only a 6% increase. The disproportionate increase in the asthma visits that occur in the month of September versus in the month of August each year (ie, the September epidemic) was blunted during the first year of the pandemic (in 2020 [Fig 1]). Table II focuses on the percentage of ED visits that were due to asthma. For 2020, there was no change in the percentage of ED visits due to asthma from August to September; however, there were increases in absolute percentage (2%-6%) during the same months for all of the other years in the data set. We did not see a similar change for asthma-related hospitalizations (data not shown).

Table I.

Comparison of all-cause and asthma-related ED encounters during August and September of each observed year

Year	No. of all-cause encounters		Difference (Δ)		No. of asthma-related encounters		Difference (Δ)
	August	September	Total	%	August	September	Total	%
2017	3584	3832	248	7%	161	393	232	144%
2018	3498	3878	380	11%	171	429	258	150%
2019	3408	3960	552	16%	156	403	247	158%
2020	2070	1970	–100	–5%	62	66	4	6%∗
2021	3051	3537	486	16%	116	220	104	89%
2022	3202	3945	743	23%	148	435	287	193%

^∗The number and percentage of encounters in 2020 were significantly lower than in the other years observed.

Fig 1.

ED asthma visit count by year and month from 2017 to 2022.

Table II.

Comparison of the proportion of asthma-related visits with that of all-cause visits in August and September of the observed years

Year	August			September
	No. of all-cause visits	No. of asthma-related visits	% of visits due to asthma	No. of all-cause visits	No. of asthma-related visits	% of visits due to asthma
2017	3584	161	4%	3832	393	10%
2018	3498	171	5%	3878	429	11%
2019	3408	156	5%	3960	403	10%
2020∗	2070	62	3%	1970	66	3%
2021	3051	116	4%	3537	220	6%
2022	3202	148	5%	3945	435	11%

^∗According to the chi-square test, the number and percentage of visits due to asthma in September of 2020 were significantly lower (P < .05) than in the 2017-2019 baseline.

As is evident in Table III, when stratified by age, the difference in the August to September change was significant (P < .05) in the younger age groups (aged <5 years and aged 5-13 years), whereas no statistically significant difference (P > .05) was seen in the older age group (aged >13 years). We used insurance type as a proxy for socioeconomic status and observed no significant difference, based on chi-square tests, when patients were stratified by Medicaid, non-Medicaid (private insurance), and self-pay, as seen in Table IV. There was no significant difference in the August to September change when data were analyzed with stratification by sex, as seen in Table E1 (available in the Online Repository at www.jaci-global.org).

Table III.

Comparison of asthma-related ED encounters during August and September of each observed year, stratified by age group

Age group	Year	August	September	Difference (Δ)
<5 y	2017	86	206	139%
	2018	88	229	160%
	2019	71	196	176%
	2020	20	21	5%
	2021	70	146	108%
	2022	99	253	155%
5-13 y	2017	40	140	250%
	2018	48	143	197%
	2019	54	145	168%
	2020	28	21	-25%
	2021	30	58	93%
	2022	40	136	240%
>13 y	2017	35	47	34%
	2018	35	57	62%
	2019	31	62	100%
	2020	14	24	71%
	2021	16	16	0%
	2022	9	46	411%

Table IV.

Asthma-related ED encounters during the months of August and September of each observed year, stratified by insurance type

Year	Month	Medicaid	Non-Medicaid	Self-pay	Total
2017	August	110 (68%)	38 (24%)	13 (8%)	161
	September	289 (74%)	87 (22%)	17 (4%)	393
2018	August	127 (74%)	38 (22%)	6 (4%)	171
	September	292 (68%)	119 (28%)	18 (4%)	429
2019	August	112 (68%)	37 (28%)	7 (4%)	156
	September	289 (71%)	98 (24%)	16 (4%)	403
2020	August	51 (82%)	10 (16%)	1 (2%)	62
	September	48 (73%)	18 (27%)	0 (0%)	66
2021	August	89 (76%)	24 (21%)	3 (3%)	116
	September	178 (81%)	37 (17%)	5 (2%)	220
2022	August	102 (67%)	46 (31%)	0 (0%)	148
	September	343 (79%)	89 (20%)	3 (1%)	435

We observed a clear decrease in the number of patients who presented to our ED for asthma evaluation and treatment in 2020. Even after controlling for the decrease in total health care utilization during the months following March 2020, the number of asthma-related ED visits decreased disproportionately during the month of September. We did not observe this trend for asthma-related hospitalizations, probably because we were underpowered to detect a difference in a 1-year period, as there are fewer asthma-related hospitalizations than asthma-related ED visits.

The yearly rise in asthma-related visits from August to September has been attributed to a combination of multiple factors, mainly, the uptick in weed pollen counts and the increased exposure to viral pathogens, especially rhinoviruses, that school aged children experience when returning to school from summer vacation.²

The 2020 school closures, as well as other measures to decrease the spread of COVID-19, halted the spread of other common respiratory viruses. This phenomenon drove most viral-induced asthma quiescent, thus blunting the September epidemic. Our observations suggest that viral exposures are an important factor for this peak in asthma exacerbations. This knowledge would suggest that strategies to either decrease viral exposures or decrease the impact of viral exposures on the airway would be important areas for future research to decrease the peak in asthma exacerbation seen in September. The often-described rebound phenomena after the pandemic or “immunity debt” is seen when there is lack of immune stimulation resulting from the reduced circulation of microbial agents. The longer these periods of “viral or bacterial low exposure,” the greater the likelihood of future epidemics,⁶ and thus, prevention of viral exposure might not be a sustainable measure. However, if the timing of the exposure is predictable, it may be possible to prevent the sequelae of the exposure (eg, bronchial hyperreactivity; asthma symptom days; and missed days of activity, school, or work).

Several interventions to decrease the impact of the September epidemic have been evaluated. One study assessing the efficacy of montelukast, a leukotriene receptor antagonist, in preventing virally induced wheezing failed to demonstrate clinical significance.⁷ But studies evaluating omalizumab, a mAb against IgE, have been successful at demonstrating reduced viral shedding in patients with asthma exacerbations and reduced the frequency of viral illnesses.⁸ Other similar medications, such as mAbs with higher affinity to IgE, have the potential to affect the September epidemic. On the basis of our observations, these interventions could be targeted to those children younger than 13 years who are at greatest risk for increases in ED use.

One limitation to our observations is the possibility that the numbers of ED visits were exaggerated in the years before 2020 and the decrease in volume observed in 2020 is thus more typical of the number of patients that truly require emergency care for their asthma.

Several large cohort studies found that patients with asthma were at reduced risk of COVID-19 hospitalization and severity,⁹ and this interaction between the virus and the patients being analyzed could have played a part in the decrease in ED visits that we observed.

Our report is limited as it is a single-center experience; however, our institution is typical of many urban medical centers. Despite these limitations, our observation suggests that the influence of viral illnesses in the yearly peak of asthma exacerbations in children can be blunted, and it should encourage investigation of proactive interventions to decrease asthma-related health care utilization in the fall season. Large, well-designed clinical trials are needed to develop strategies to blunt the school absenteeism, missed parental work, and long-term health impacts associated with the September epidemic.

Clinical implications.

Our observation suggests that there may be remediable risk factors contributing to the “September epidemic” that can be used to guide future interventions for managing pediatric asthma.

Disclosure statement

Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest.