Characteristics of pediatric transplant patients during COVID-19
Patient characteristics in three time periods (“Early” Jan 1 – Mar 15 2020, “Middle” Mar 16 – Apr 30 2020, and “Late” May 1 – Jun 30 2020) were examined (Table 1). Patients who received a kidney transplant during the first COVID-19 peak in the United States, Middle period, had similar waitlist time, cPRA and blood type compared to Early and Late periods (p > 0.1). Higher proportion of Black patients received a transplant in the Middle (30.6%) compared to Early (13.1%) and Late (20.7%), (p=0.28). Living donor transplants made up a smaller proportion of total transplants during the Middle period 13.9%, compared to 29.5% and 36.4% in Early and Late, respectively (p=0.035). Median cold ischemia time (CIT) was longer in the Middle period 10.2 hours (IQR 6.5-17.4), compared to the Early 9.0 hours (IQR 4.0-13.2) and Late 7.6 hours (IQR 2.4-10.7) periods, (p=0.02).
Weekly count of waitlist changes
National weekly pediatric KT waitlist additions ranged from 7 - 41 cases per week between February 2 and June 30, 2020. There was a trend of decreasing new pediatric DDKT registrations, following the national rise of COVID-19 cases mid-March. Since April, none of the weekly pediatric KTs exceeded 21, the 2017- 2019 average counts for the same period (Figure 1A). The numbers of registrants who changed to inactive status also increased in March, with 77.2% of registrants who changed to inactive status in the third and fourth week of March indicating COVID-19 as reason of inactivation (Figure 1C). COVID-19 was added as a refusal code or cause for change in status in UNET on March 25, 2020; however, this classification does not differentiate new COVID-19 infection in the patient vs precaution secondary to the pandemic.
Percentage of inactive waitlist registrants rose from 72% to 77% between March 1 and April 15, and remained elevated above previous baseline thereafter (Figure 1D). We observed an increasing trend in waitlist removal due to death or deteriorating condition since March, followed by a trend that returned to previous benchmarks by late-April (Figure 1B).
Weekly count of transplant events
The national weekly pediatric DDKT volume ranged from 0-16 cases per week between February 1 and June 30, 2020. On average, the weekly DDKT volume in 2017-2019 was 9.6 cases. Between mid-March and the end of June 2020, DDKT volume remained lower than 9.6 except for 4 weeks out of the 15 during observation. There was a trend of decreasing DDKT and LDKT volume seen since March, followed by increase from mid-April to end of June (Figure 2A, 2B). For LDKT, the weekly volumes were never above the 2017-2019 average between mid-March and May 31, but consistently surpassed this volume in June 2020 (Figure 2B).
Regional and National Imports
Overall numbers of regional and national imports were extremely low (0-4 per week), with average <1 import per week in 2017-2019 (Figure 2C). During the early period of COVID-19 disease activity in the United States, imports were more common than in previous years. As the pandemic progressed, there was a decline in imports, however the average number of imports continue to remain higher than previous years.
Comparing the observed and predicted waitlist changes
The overall observed national volume of waitlist registration was lower (-13.3%, p=0.021) and change to inactive waitlist status was higher (57.2%, p<0.001) compared to the expected volume during March 15 – June 30, 2020 (Table 2). When stratified into the earlier (March 15 – April 30, 2020) and the latter (May 1– June 30, 2020) periods, 6 candidates were removed from the waitlist during the earlier period due to death or deteriorated condition, which was 189% more than the expected 2.1 cases (p=0.005). Similarly, 83 candidates had changed to inactive status during the earlier period, which was 152% more than the expected 32.9 cases (p<0.001). In both cases, the significance was not achieved in the latter period (11.3%, p=0.3 and -11.1%, p=0.5, respectively). Contrarily, the observed counts of new waitlist registration was 23.8% lower compared to the expected during the latter period (p=0.002), though not significantly different in the earlier period (0.4%, p=1.0).
Comparing the observed and predicted transplant events
There were 157 pediatric KTs performed during March 15-June 30, 2020 (108 DDKT, 49 LDKT), which was 22.8% fewer than the expected 203.3 cases (p=0.001). The 108 DDKT performed during the same period was 29.2% fewer than the expected 103.1 cases (p=0.03), whereas the 49 LDKTs was not significantly different from the expected 64.2 cases (p=0.058). When stratified to the earlier and the latter COVID-19 eras, the observed DDKT, LDKT, and combined total transplant were all significantly less than expected in the earlier era (total: 36 vs. 88.5, -59.3%, p<0.001; LDKT: 5 vs. 27.9, -82.1%, p<0.001; DDKT: 31 vs. 59.1%, -47.6%, p<0.001) but not during the latter period.
Regional differences in transplant practice and waitlist death by COVID-19 burden
Centers situated in states with high COVID-19 burden (NY, NJ, RI, MA, DC, CT,LA, DE, IL, MD, AZ, NE, IA, NS) between March 15 and June 30 had significantly fewer new waitlist registrations (incidence rate ratio (IRR): 0.49 0.65 0.85) and LDKT (IRR: 0.17 0.38 0.84) compared to centers in states with low burden (IRR: 0.82 0.94 1.08) (Table 3). There were no differences in the proportion of expected DDKT and waitlist death between centers in states with high and low COVID-19 burden.