the effect of missed hemodialysis sessions on the occurrence of short-term cardiovascular events in patients with end-stage renal disease receiving maintenance hemodialysis.

End-stage renal disease (ESRD) represents a major and growing global health burden, with a steadily increasing prevalence worldwide. Patients receiving maintenance hemodialysis (HD) experience markedly elevated rates of cardiovascular morbidity and mortality compared with the general population (1).

Cardiovascular disease accounts for nearly half of all deaths among HD patients, reflecting the combined effects of traditional cardiovascular risk factors and dialysis-specific stressors, including large volume shifts, electrolyte disturbances, chronic inflammation, and autonomic dysfunction (2).

Maintenance HD is designed to preserve physiological homeostasis through regular removal of excess fluid, electrolytes, and uremic toxins. Adherence to the prescribed dialysis schedule is therefore essential for maintaining cardiovascular stability (3).

Despite its life-sustaining role, HD is an inherently complex and time-consuming therapy, typically delivered three times weekly for several hours per session. This demanding regimen imposes substantial physical, psychological, and socioeconomic burdens on patients and contributes to persistently high rates of hospitalization and mortality (4).

Missed HD sessions or delays in treatment represent a common and clinically significant challenge in routine dialysis care, with observational studies indicating that 515% of patients miss at least one scheduled session annually. Disruption of the regular dialysis schedule results in prolonged interdialytic intervals and loss of metabolic and volume control (5).

Importantly, missed treatments are not solely attributable to patient nonadherence. A wide range of contributing factors has been identified, including logistical barriers such as unreliable transportation, long travel times to dialysis units, adverse weather conditions, and scheduling of sessions on weekends or holidays. Medical factors such as gastrointestinal symptoms, vascular access dysfunction, chronic pain, depression, and substance use further contribute to treatment nonattendance. Additionally, demographic and psychosocial factors, including older age, limited health literacy, race or ethnicity, and lack of social or marital support, play an important role (6).

The consequences of missed HD sessions extend beyond inadequate solute clearance. Prolonged interdialytic intervals lead to acute physiological derangements, including progressive fluid overload, worsening hypertension, hyperkalemia, metabolic acidosis, and accumulation of uremic toxins. These abnormalities impose significant myocardial stress and increase electrical instability (7).

The cardiovascular system of HD patients is particularly vulnerable to abrupt changes in preload and afterload. Excess interdialytic weight gain following missed sessions increases cardiac workload and predisposes patients to acute heart failure decompensation. Concurrently, electrolyte disturbances particularly hyperkalemia may precipitate malignant arrhythmias, while autonomic imbalance and heightened sympathetic activity further amplify the risk of sudden cardiac events (8).

Consistent with these pathophysiological mechanisms, studies comparing scheduled dialysis days have demonstrated higher rates of cardiovascular events following longer interdialytic gaps. Moreover, skipped treatments have been associated with sharply increased short-term risks of hospitalization and mortality, particularly within 4872 hours the missed session (9).

Additionally, Missed HD sessions have also been linked to unfavorable anemia-related outcomes, including lower hemoglobin levels and increased requirements for erythropoiesafteris-stimulating agents, further reflecting compromised dialysis adequacy

Inclusion Criteria:

• Adult patients aged ≥18 years.
• Patients diagnosed with end-stage renal disease (ESRD).
• Patients receiving maintenance hemodialysis on a regular schedule (three sessions per week).
• Patients on maintenance hemodialysis for at least 3 months prior to enrolment.

Exclusion Criteria:

• Patients receiving peritoneal dialysis or other forms of renal replacement therapy.
• Patients with acute kidney injury requiring temporary dialysis.
• Patients with documented acute cardiovascular events within 30 days prior to study enrolment.
• Patients who undergo renal transplantation during the study period.

Hemodialysis Unit of Internal Medicine Department