Impact of lockdown on cardiovascular disease hospitalizations in a Zero-COVID-19 country

Abstract

Objectives: There are concerns about the potential effect of social distancing used to control COVID-19 on the incidence of cardiovascular diseases (CVD).

Study design: Retrospective cohort study.

Methods: We examined the association between lockdown and CVD incidence in a Zero-COVID country, New Caledonia. Inclusion criteria were defined by a positive troponin sample during hospitalization. The study period lasted for 2 months, starting March 20, 2020 (strict lockdown: first month; loose lockdown: second month) compared with the same period of the three previous years to calculate incidence ratio (IR). Demographic characteristics and main CVD diagnoses were collected. The primary endpoint was the change in incidence of hospital admission with CVD during lockdown compared with the historical counterpart. The secondary endpoint included influence of strict lockdown, change in incidence of the primary endpoint by disease, and outcome incidences (intubation or death) analyzed with inverse probability weighting method.

Results: A total of 1215 patients were included: 264 in 2020 vs 317 (average of the historical period). CVD hospitalizations were reduced during strict lockdown (IR 0.71 [0.58-0.88]), but not during loose lockdown (IR 0.94 [0.78-1.12]). The incidence of acute coronary syndromes was similar in both periods. The incidence of acute decompensated heart failure was reduced during strict lockdown (IR 0.42 [0.24-0.73]), followed by a rebound (IR 1.42 [1-1.98]). There was no association between lockdown and short-term outcomes.

Conclusions: Our study showed that lockdown was associated with a striking reduction in CVD hospitalizations, independently from viral spread, and a rebound of acute decompensated heart failure hospitalizations during looser lockdown.

Keywords: Acute coronary syndrome; COVID-19; Epidemiology; Heart failure; Hospitalization; Lockdown; Myocardial infarction; SARS-CoV-2.

Fig. 1

Number of hospital admissions in Centre-Hospitalier-Territorial according to the study period and the historical cohort. (A) Emergency department admissions. (B) The number of hospital admissions. (C) Intensive care unit (ICU) admissions. (D) The number of patients with a positive troponin sample included in the study. Data were collected from the March 20 till May 20, 2020, and were compared with the same period of the three previous years (i.e. historical period).

Fig. 2

Incidence of hospitalizations with a positive troponin sample and associate diagnosis during the strict lockdown month of the study period in 2020 (blue line) and during the looser lockdown (yellow line) compared with their historical counterpart of the three previous years. The results are expressed as incidence ratios (IRs) and 95% confidence interval. A P-value of interaction between the strict lockdown and the loose lockdown period was considered as significant when <0.05. ICU, intensive care unit; IR, incidence ratio; NSTEMI, non-ST-segment elevation myocardial infarction; STEMI, ST-segment elevation myocardial infarction; 95% CI, 95% confidence interval. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)