Discussion
By use of a large multihospital database, we examined the impact of the first year of the covid-19 pandemic on acute care of AIS and AMI in the US. Our study documents an important reduction in all measured metrics for AIS and AMI care, including the change in numbers of admissions for AIS (−13.59%) and AMI (−17.20%) during the pandemic versus before the pandemic. We also noted significant decreases in volumes for intravenous thrombolysis (−9.47%) as well as any percutaneous coronary intervention (−17.89%) and percutaneous coronary intervention for AMI only (−14.36%). Although the comparative mechanical thrombectomy changes in relation to the prior year were presumably masked by the temporal increases in mechanical thrombectomy volumes observed over the recent years (as suggested by the March 2019 to March 2020 trends in figure 2),23 24 comparison of the first three pandemic months with three months immediately preceding the pandemic showed a 11.26% reduction in mechanical thrombectomy procedures. This mirrors the decline described across the same three month periods in a recent large multicenter global analysis.25 Notably, the extent of the changes in AIS and AMI care had a distinct temporal correlation with spikes in deaths related to covid-19 (figures 1 and 2). Additionally, adjusted rates of mortality in hospital increased for both AIS and AMI while length of stay was shorter for AMI but not AIS.
Our results are in alignment with several previous studies that showed significant reductions in the care for AIS and AMI during the first wave of covid-19 pandemic worldwide.25–31 However, prior studies were largely focused on the first few months of the pandemic and, until now, whether these effects would be limited to the early phases or would continue to occur throughout the pandemic was unclear. In this context, a few recent studies have suggested a potential recovery in the volumes of AIS and AMI care over the subsequent months of the pandemic.26–29 Although our study showed similar trends over these same periods, our findings show that, in the longer term, the collateral effects of the pandemic over the care of AIS and AMI seem to reliably recur with any new upsurges in covid-19, suggesting that systems of care and populational behaviors did not readapt over time.
Among patients being admitted with a diagnosis of AIS or AMI during the covid-19 period, we observed an increase in treatment rates as compared with those for patients admitted before covid-19 emergence. The observed relative increase in the reperfusion treatment rates suggests a shift towards greater clinical severity for patients in hospital during the pandemic. AIS studies have reported a greater reduction in the admissions for transient ischemic attack and mild strokes compared with more severe stroke presentations.3 8 Similarly, acute coronary syndromes studies showed greater reductions in volumes for unstable angina and non-ST-elevation myocardial infarction than for ST-elevation myocardial infarction.13 17 32 Notably, the outbreak appears to have not only impacted AIS and AMI treatment volumes but also their workflow leading to increases in times from symptom onset to first medical contact and door to reperfusion for both conditions.8 10 12 33–35
A particularly important novel finding of our study is the significantly higher mortality in hospital for AIS and AMI over the first year of the pandemic. Although we could not find a convincing explanation for the reported increase in mortality, the aforementioned workflow delays combined with the relative increase in disease severity were presumably main contributors to the increased mortality in hospital. Additionally, despite their overall low frequency, patients presenting with concomitant diagnosis of covid-19 and AIS or AMI are known to have much poorer outcomes.36 37 Such combined presentations might have contributed to observed increases in mortality. The observed length of stay changes in AMI were possibly a reflection of pressures on healthcare systems to improve efficiencies of hospital resources, such as accelerated treatment and discharge, to reduce risks of viral exposure and optimize bed capacity during the pandemic.
Our study is limited by the design of any retrospective analysis, such as the availability of data for relevant clinical outcomes. Although we could assess patient comorbidity status, clinical metrics such as modified Rankin scale scores were not available. We also tried to be comprehensive as much as we could by including hospitals with a minimum criterion of admissions of ‘one’ during the study period. This criterion could have created some noise in the data and would limit hospitals that have some minimum threshold enough to get stable estimates. Additionally, sampling could be a possible limitation that could affect generalizability given that Premier Healthcare Database collects data from voluntary participating hospitals with possible selection bias. Furthermore, some of the absolute differences observed were small and might not be clinically relevant. We only had missing data for race and marital status. The rate of missing data for patients with AIS in precovid-19 period sample was 2.98% and for postcovid-19 period was 3.49%. The rate of missing data for AMI patients in precovid-19 period sample was 2.33% and for post-covid-19 period was 2.90%. Given the small proportion of missing information, we do not expect our results to have been affected by removal of patients with missing data. Moreover, billing and coding errors, especially as hospitals face logistical and administrative stress during the pandemic, could have influenced the accuracy of study results.
Conclusions
This large multihospital database analysis adds to the increasing evidence evaluating the side effects of the covid-19 pandemic in the treatment and outcomes for acute care conditions across US hospitals. Although improved efficiencies in hospital length of stay were observed in AMI during the covid-19 era, inpatient mortality for AIS and AMI was higher and the number of hospital admissions was lower than expected. The persistence of these deleterious effects one year into the pandemic is particularly troublesome. Many factors could be considered including reduced capacity at hospitals, changes in service organisation and how to access care, and delays due to health services and intensive care facilities being overwhelmed. From a public policy perspective, public health interventions (eg, awareness media campaigns and relevant health education) should be used to engage and inform the public about the effects of untreated acute conditions and to prevent these observed decreases in patient admissions to hospital in future pandemics.