Systematic Review

Instructor: Cathleen Colon-Emeric, MD
Email: colon001@mc.duke.edu

 Learning goals:

  • Describe methods used by authors to ensure that all relevant studies were included.
  • Name several parameters for assessing the validity of various studies considered for inclusion in a systematic review.
  • Describe how consistency between studies is measured, both graphically and statistical

Case:

You are serving on an advisory panel for the Centers for Medicare and Medicaid Services (CMS), and your role is to make recommendations on whether or not Medicare should cover various procedures, devices, and drugs. Your group has been asked to review the evidence for the effectiveness of implantable cardioverter-defibrillators (ICDs) for the primary prevention of sudden cardiac death in Medicare beneficiaries with systolic congestive heart failure (CHF). With the aging population, CHF prevalence is rapidly increasing and is currently the leading cause for hospitalization in adults over age 65. Each device costs $25,000, and in 2006 CMS spent $4.6 billion on ICDs.

In 2008, the American College of Cardiology recommended ICDs for patients with class I-III ischemic or non-ischemic CHF and ejection fracture (EF) < 30-35%. The recommendation was class 1 (strongest endorsement), and was based on clinical trials graded A or B (best quality evidence). However, more than half of the patients enrolled in these trials were younger than 60 years, and in 2010, a systematic review and meta-analysis was published which questioned the efficacy of ICDs in patients over age 65 years; the population served by Medicare.

Your advisory panel is asked to answer the following questions:

  1. Among all the trials addressing this clinical question, what range of results were observed in the group over age 60-65 years?
  2. Were the results similar from study to study?
  3. What is your best estimate of the effectiveness of ICDs in the Medicare population with systolic CHF?
  4. How confident are you about that estimate?
  5. Do you recommend that CMS continue covering ICDs for this indication, or revoke coverage benefits?