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Day-Night Pattern of Sudden Death in Obstructive Sleep Apnea
Arrhythmias
Results: The ICD was estimated to prolong life by a mean of 1.8 years, at an incremental cost of $90,829. The costeffectiveness of the ICD was $50,500 per life-year gained and was dependent on time horizon. Over a 3-year time horizon, cost-effectiveness was $367,200 per life-year gained, compared to $67,800 per life-year saved over a 15-year time horizon. Conclusions: In a population of patients with prior infarction and an EF ⱕ0.30, the ICD prolongs survival by 1.8 years at an incremental cost of approximately $50,000 per life-year saved. Perspective: Therapies associated with an incremental cost of ⱕ$50,000 per life-year saved are considered to have favorable cost-effectiveness, and ICDs used for primary prevention in a MADIT-II population fall into this category. Nevertheless, cost-effectiveness of the ICD in these types of patients could be substantially improved with more effective techniques for risk stratification. FM
Abstracts Day-Night Pattern of Sudden Death in Obstructive Sleep Apnea Gami AS, Howard DE, Olson EJ, Somers VK. N Engl J Med 2005;352:1206 –14. Study Question: Are patients with obstructive sleep apnea (OSA) at increased risk of nocturnal sudden cardiac death (SCD)? Methods: This was a retrospective review of 112 patients (mean age 69 years) with SCD who had undergone prior polysomnography. The frequencies of SCD at various times of day in 78 patients with OSA were compared to the corresponding frequencies in the 34 patients without OSA and in a historical control population of 19,390 individuals with SCD. Results: A significantly higher proportion of SCDs occurred between midnight and 6 a.m. in patients with OSA (46%) than in patients without OSA (21%) or in the control group (16%). The relative risk (RR) of SCD between midnight and 6 a.m. was related to the severity of the OSA (RR 1.9 for mild–moderate OSA and 2.6 for severe OSA). Conclusions: SCD is most likely to occur during sleep in patients with OSA. Perspective: OSA is associated with hypoxemia, hypercapnia, increased adrenergic tone, blood pressure surges, hypercoagulability and endothelial dysfunction. Some or all of these factors may account for the increased risk of nocturnal SCD in patients with OSA. However, because only patients with SCD were included in the study, the question of whether OSA increases the overall risk of SCD (as opposed to only affecting the time distribution of SCDs) is unanswered. Another important issue that requires clarification is the impact of treatment with continuous positive airway pressure on the risk of nocturnal SCD in patients with OSA. FM
Conventional and Atypical Antipsychotics and the Risk of Hospitalization for Ventricular Arrhythmias or Cardiac Arrest Liperoti R, Gambassi G, Lapane KL, et al. Arch Intern Med 2005;165:696 –701. Study Question: Does the use of antipsychotic medication increase the risk of cardiac arrest or ventricular tachycardia/ ventricular fibrillation (VT/VF)? Methods: This retrospective case-control study was based on review of a standardized database of nursing home residents and Medicare inpatient claim files. Cases (n⫽649) were identified by an admission diagnosis of cardiac arrest or VT/VF, and controls (n⫽2962) were identified by nonarrhythmia-related admission diagnoses. A geriatric drug database was used to identify exposure to conventional (most commonly haloperidol) and atypical (most commonly risperidone) antipsychotics. Results: The use of a conventional antipsychotic agent was independently associated with an 86% increase in the risk of hospitalization for cardiac arrest or VT/VF. Atypical antipsychotics were not associated with hospitalizations for cardiac arrest or VT/VF. Among patients with structural heart disease, conventional antipsychotics were associated with a 3.3-fold increase in the risk of hospitalization for cardiac arrest or VT/VF. Conclusions: Conventional, but not atypical, antipsychotic medications increase the risk of cardiac arrest and VT/VF. Perspective: Conventional antipsychotic agents such as haloperidol and thioridazine precipitate VT/VF by prolonging the QT interval. Bradycardia markedly increases the risk of torsades de pointes when there is QT-interval prolongation. Therefore, it is advisable to avoid the use of any QT-prolonging agent in the setting of bradycardia or sick sinus syndrome, both of which are fairly common in geriatric patients. FM
Clinical and Economic Implications of the Multicenter Automatic Defibrillator Implantation Trial–II. Al-Khatib SM, Anstrom KJ, Eisenstein EL, et al. Ann Intern Med 2005;142:593– 600. Study Question: What is the cost-effectiveness of the implantable cardioverter-defibrillator (ICD) when used for primary prevention in patients with prior infarction and an ejection fraction (EF) ⱕ0.30? Methods: A cost-effectiveness analysis of the ICD versus conventional medical therapy in patients with prior infarction and an EF ⱕ0.30 was performed based on the Duke University database, Medicare data and published literature.
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Results: The ICD was estimated to prolong life by a mean of 1.8 years, at an incremental cost of $90,829. The costeffectiveness of the ICD was $50,500 per life-year gained and was dependent on time horizon. Over a 3-year time horizon, cost-effectiveness was $367,200 per life-year gained, compared to $67,800 per life-year saved over a 15-year time horizon. Conclusions: In a population of patients with prior infarction and an EF ⱕ0.30, the ICD prolongs survival by 1.8 years at an incremental cost of approximately $50,000 per life-year saved. Perspective: Therapies associated with an incremental cost of ⱕ$50,000 per life-year saved are considered to have favorable cost-effectiveness, and ICDs used for primary prevention in a MADIT-II population fall into this category. Nevertheless, cost-effectiveness of the ICD in these types of patients could be substantially improved with more effective techniques for risk stratification. FM
Abstracts Day-Night Pattern of Sudden Death in Obstructive Sleep Apnea Gami AS, Howard DE, Olson EJ, Somers VK. N Engl J Med 2005;352:1206 –14. Study Question: Are patients with obstructive sleep apnea (OSA) at increased risk of nocturnal sudden cardiac death (SCD)? Methods: This was a retrospective review of 112 patients (mean age 69 years) with SCD who had undergone prior polysomnography. The frequencies of SCD at various times of day in 78 patients with OSA were compared to the corresponding frequencies in the 34 patients without OSA and in a historical control population of 19,390 individuals with SCD. Results: A significantly higher proportion of SCDs occurred between midnight and 6 a.m. in patients with OSA (46%) than in patients without OSA (21%) or in the control group (16%). The relative risk (RR) of SCD between midnight and 6 a.m. was related to the severity of the OSA (RR 1.9 for mild–moderate OSA and 2.6 for severe OSA). Conclusions: SCD is most likely to occur during sleep in patients with OSA. Perspective: OSA is associated with hypoxemia, hypercapnia, increased adrenergic tone, blood pressure surges, hypercoagulability and endothelial dysfunction. Some or all of these factors may account for the increased risk of nocturnal SCD in patients with OSA. However, because only patients with SCD were included in the study, the question of whether OSA increases the overall risk of SCD (as opposed to only affecting the time distribution of SCDs) is unanswered. Another important issue that requires clarification is the impact of treatment with continuous positive airway pressure on the risk of nocturnal SCD in patients with OSA. FM
Conventional and Atypical Antipsychotics and the Risk of Hospitalization for Ventricular Arrhythmias or Cardiac Arrest Liperoti R, Gambassi G, Lapane KL, et al. Arch Intern Med 2005;165:696 –701. Study Question: Does the use of antipsychotic medication increase the risk of cardiac arrest or ventricular tachycardia/ ventricular fibrillation (VT/VF)? Methods: This retrospective case-control study was based on review of a standardized database of nursing home residents and Medicare inpatient claim files. Cases (n⫽649) were identified by an admission diagnosis of cardiac arrest or VT/VF, and controls (n⫽2962) were identified by nonarrhythmia-related admission diagnoses. A geriatric drug database was used to identify exposure to conventional (most commonly haloperidol) and atypical (most commonly risperidone) antipsychotics. Results: The use of a conventional antipsychotic agent was independently associated with an 86% increase in the risk of hospitalization for cardiac arrest or VT/VF. Atypical antipsychotics were not associated with hospitalizations for cardiac arrest or VT/VF. Among patients with structural heart disease, conventional antipsychotics were associated with a 3.3-fold increase in the risk of hospitalization for cardiac arrest or VT/VF. Conclusions: Conventional, but not atypical, antipsychotic medications increase the risk of cardiac arrest and VT/VF. Perspective: Conventional antipsychotic agents such as haloperidol and thioridazine precipitate VT/VF by prolonging the QT interval. Bradycardia markedly increases the risk of torsades de pointes when there is QT-interval prolongation. Therefore, it is advisable to avoid the use of any QT-prolonging agent in the setting of bradycardia or sick sinus syndrome, both of which are fairly common in geriatric patients. FM
Clinical and Economic Implications of the Multicenter Automatic Defibrillator Implantation Trial–II. Al-Khatib SM, Anstrom KJ, Eisenstein EL, et al. Ann Intern Med 2005;142:593– 600. Study Question: What is the cost-effectiveness of the implantable cardioverter-defibrillator (ICD) when used for primary prevention in patients with prior infarction and an ejection fraction (EF) ⱕ0.30? Methods: A cost-effectiveness analysis of the ICD versus conventional medical therapy in patients with prior infarction and an EF ⱕ0.30 was performed based on the Duke University database, Medicare data and published literature.
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