Post-COVID Syndrome in Patients With Comorbid Hypertension or Diabetes: A Narrative Review of Long-Term Outcomes

Post-COVID syndrome (PCS), or long COVID, refers to a cluster of enduring symptoms that extend beyond the acute phase of the initial SARS-CoV-2 infection. Acute infection predominantly impacts the respiratory tract, but there is growing evidence for the multisystem involvement, such as cardiovascular, metabolic, and neurological, to be responsible for the prolonged presentation in PCS. Underlying cardiometabolic vulnerability may contribute to a high degree of susceptibility in patients with comorbidities like hypertension (HTN) and diabetes mellitus (DM). This narrative review summarizes current literature regarding PCS in patients with HTN and/or DM, focusing on proposed pathophysiological mechanisms, clinical manifestations, and reported long-term outcomes. In these populations, PCS has been linked across studies to processes including endothelial dysfunction, chronic low-grade inflammation, autonomic imbalance, and potential dysregulation of the renin-angiotensin-aldosterone system (RAAS). Persistent cardiovascular, metabolic, and neurocognitive symptoms are reported, but the magnitude and patterns of risk vary across studies, while comparative findings across HTN and DM remain heterogeneous. Symptoms reported frequently include fatigue, cognitive impairment ("brain fog"), and psychological distress, supporting the multisystem complexity of PCS. Although, previous work has indicated that cardiometabolic comorbidities could interact and moderate PCS severity and persistence, there is an important shortfall of both causality and prognosis, as well as the management of PCS. Longitudinal studies are needed for future research regarding risk stratification, disease course, and targeted interventions in individuals with PCS with comorbid high blood pressure and diabetes.