Impact of Deferred Clinic Visits on Patients With Cardiovascular Comorbidities: A Prospective Cohort Study

Introduction Hypertension, diabetes and dyslipidaemia are key cardiovascular risk factors (CVRF) that contribute to adverse cardiovascular events and increase the risk of premature deaths from cardiovascular causes(1-3). Effective management of these risk factors is crucial in reducing the incidence of adverse vascular events such as stroke or myocardial infarction. Currently recommendations suggest follow-up intervals of 3 to 12 months for stable patients, but these recommendations are mostly arbitrary (1, 3-5). The association between more frequent follow-ups and improved cardiovascular risk factor control remains unclear, with conflicting data on its effectiveness (6-10). Notably, no prospective studies have examined the feasibility and safety of extended follow-up intervals beyond 6 months in patients with these CV risk factors. The COVID-19 pandemic introduced a unique challenge, as concerns about person-to-person transmission led many patients to voluntarily defer their scheduled clinic visits. This study aims to prospectively assess the impact of extended follow-up intervals on disease management and risk factors control in patients with CVRF.

Method This single-centre, prospective cohort study compared CVRF control between patients who deferred their physical clinic visit and those who attended as scheduled. The study protocol was approved by the Jointed Chinese University of Hong Kong and North Territory East Cluster Clinical Research Ethic Committee. All patients provided written informed consent data collection. This study followed The Strengthening the Reporting of Observational studies in Epidemiology (STROBE) guidelines for cohort studies reporting.

Setting This study was conducted at the Medical Specialist Outpatient Clinics of the Prince of Wales Hospital, a tertiary regional teaching hospital in Hong Kong, from April 2020 to January 2022. This timeframe was selected to coincide with the implementation of the Drug Refilling Clinic Scheme during the COVID-19 pandemic, which allowed patients to voluntarily defer their scheduled clinic visits while receiving medications from their last prescription for their chronic conditions via postal delivery. Data was collected from clinical notes and the electronic health records.

Participants Patients were recruited if they have at least one of three CVRF: diabetes, hypertension, or dyslipidaemia. Patient newly diagnosed with these conditions were excluded. Additionally, unstable patients defined as those with a history of hospitalization or emergency department visit within the preceding three months, those with complex medical problems indicated by a Charlson Comorbidity Index (CCI)(11) of equal or greater than five, or those whose primary medical issues were unrelated to cardiovascular disease - were excluded. Patients who defaulted their subsequent follow-up appointments with no recorded clinic visit by the end of the study period were also excluded. The study flow is summarized in figure 1.

Patients who deferred their appointment were categorized into the 'deferred' group, while those who attended their appointment as scheduled were placed in the 'control' group. Patients in the deferred group received a prescription refill by post along with a new appointment date. They were instructed to seek medical attention if they experienced any health concerns between follow-up intervals. Routine Blood test including lipid profile, HbA1c and other standard assessments, were conducted at the time of their next clinic visit. Additionally, they were instructed to monitor and record their blood pressure and glucose level at home with these records reviewed during the new follow-up appointments. Patients in the control group followed the standard local practice of clinic visits at intervals of 3 to 6 months. These patients were randomly selected from the list of clinic attendees and screened for eligibility at a 2:1 ratio to the 'deferred' group. A 2:1 ratio was used as more patients attended their scheduled visits than deferring. Similar blood test was performed during each clinic visit, as in the deferred group.