Effects of deferment of clinic visit on cardiovascular outcomes during COVID-19 outbreak: a prospective cohort study

Abstract Background Current guidelines recommend 3-6 months interval outpatient follow-up for patients with cardiovascular (CV) diseases and risk factors such as hypertension, diabetes mellitus (DM) and dyslipidemia. The impact of longer follow-up intervals is unclear. From 2020 to 2022, due to the infection control measures for COVID-19 pandemic, many patients voluntarily deferred their scheduled clinic visits. This provided us with an opportunity to study the impact of prolonged visit intervals on management CV risk factors. Purpose We aimed to investigate the impact of prolonged clinic visit intervals on CV outcomes and CV risk factor management among patients with CV diseases. Methods Patients with at least 1 CV risk factor (DM, hypertension, dyslipidemia, or a history of CV disease) were recruited from cardiology outpatient clinics from a tertiary teaching hospital from 2020-2022. Patients who opted to defer their appointment (Deferred group) were compared to those who attended their scheduled appointment (Normal group). The primary outcomes were composite major adverse cardiovascular events (MACE) of myocardial infarction, stroke, or CV-related death. The secondary outcomes were any unscheduled hospitalizations, suboptimal DM control (haemoglobin A1C >7%) or hyperlipidemia (LDL > 1.4 mmol/L). Results Out of the 455 patients recruited from outpatient clinics, 162 patients (35.6%) opted to defer their scheduled clinic visit (mean age 64.7 ± 12, 37.7% female), and 293 patients (mean age 64.5 ± 10, 36.2% female) continued to attend their appointments. The mean appointment interval was 226 days for the normal group and 582 days for the deferred group (p< 0.001). There was no significant difference in the primary outcome of MACE between the ‘Normal’ group and the ‘Deferred’ group (2.5% vs 0.6%, p=NS). The number of patients with suboptimal DM control (11.4% vs 21.9%, p = 0.029) was higher in the deferred group, whereas suboptimal hyperlipidemia (73.1% vs 77.1%, p=NS) was not statistically different. There were a total of 27 of unscheduled hospitalizations, among which the majority was for CV-related events (63.0%). Patients in the ‘Deferred’ group had higher rates of unscheduled hospitalization (12.3% vs 2.4%, p < 0.001) and higher rate of CV-related hospitalization compared to the ‘Normal’ group (6.2% vs 2.4%, p=0.041). Conclusion Our prospective data demonstrates that a prolonged clinic visit interval of more than 365 days was not associated with significant increase in adverse CV event or worsening of lipid control. However, prolonged clinic visit interval was associated with worse DM control and more frequent unscheduled hospitalization. More frequent medical contact might allow timely management of medical emergency at the outpatient setting and contribute to the lower rate of hospitalization in the routine follow-up group.