The Centers for Medicare and Medicaid Services (CMS) have partnered with the Agency for Healthcare Research and Quality (AHRQ) to commission a review of NPWT devices as required by the MIPPA legislation. AHRQ contracted with one of its Evidence-based Practice Centers (EPCs), the ECRI Institute EPC, to perform the review. The purpose of this review is to provide information to CMS to consider along with other inputs in evaluating HCPCS coding for NPWT devices. CMS will use this review in its assessment of whether existing HCPCS codes adequately reflect the range of NPWT devices on the market today.
The process of systematic review as practiced by the EPC Program follows specific prescribed steps:
1. The investigators start with formulated key questions. These questions test hypotheses and are structured using the following framework: patients, intervention of interest, comparator, and outcomes. EPC are encouraged to focus on outcomes that are relevant and important to patients (patient-oriented outcomes). The framework is depicted visually in the “analytic framework” that the EPC program uses to show the relationship between the key questions and the outcomes used to address these questions.
2. Inclusion and exclusion criteria for studies to be used in the review are determined based on the specific questions to be addressed. Criteria may vary for each question in the review.
3. Next, an objective and comprehensive search of the medical literature and “gray literature,” (i.e., reports, monographs and studies produced by government agencies, educational facilities and corporations that do not appear in the peer-reviewed literature) is conducted. The reference lists of included studies are examined for any studies not identified by electronic searches.
4. Studies are compared to the inclusion criteria developed prior to examining the evidence, and those included in the review are then critically appraised, noting features of the design and conduct of the studies that create potential for bias. Bias, in this context, is a study feature that could impact whether the treatment being studied is responsible for the outcomes observed. Studies with a low potential for bias are typically described as being of “high quality,” whereas those with high potential for bias are described as being of “low” or “poor” quality, and those of moderate quality as having intermediate potential for bias. The degree to which a study protects against bias is referred to as “internal validity.” Following this appraisal, data are extracted from the included studies and analyzed or summarized as appropriate.
After receiving the work assignment for this review in December, 2008, AHRQ developed the following Key Questions:
1. Does any single NPWT system have a significant therapeutic distinction in terms of wound healing outcomes compared to any other NPWT system for the treatment of acute or chronic wounds?
2. Does any component of a NPWT system have a significant therapeutic distinction in terms of wound healing outcomes compared to any other similar component of a NPWT system for the treatment of acute or chronic wounds?
3. What are the reported occurrences of pain, bleeding, infection, other complications, and
mortality for NPWT systems?
4. Do patients being treated with one NPWT system have a significant therapeutic
distinction in terms of less pain, bleeding, infection, other complications, or mortality
than other NPWT systems?
For the purpose of addressing these Key Questions, AHRQ considered any NPWT system or component commercially marketed within the past 20 years. Next, an assessment of the potential for bias of the included studies was performed using a quality assessment instrument developed by ECRI Institute for comparative studies and the Assessment of Multiple Systematic Reviews (AMSTAR) measurement tool for systematic reviews of the literature.
Evidence for Negative Pressure Wound Therapy
Key Question 1: No studies directly comparing one NPWT system to another NPWT system that addressed this Key Question were identified by our searches or in the materials submitted by interested parties.
Key Question 2: No studies directly comparing one NPWT component to another NPWT component that addressed this Key Question were identified by our searches or in the materials submitted by interested parties.
Key Question 3: Adverse events were reported in 37 of 40 studies comparing NPWT to other treatments. Of the 37 studies reporting events, seven (19%) studies described NPWT as a safe treatment. Fewer complications were reported in the NPWT-treated patients than in those receiving other wound therapies in 19 (51%) studies and similar complications were reported in 8 (22%) studies. Adverse events reported in 103 case series included pain (k = 12), bleeding (k = 7), infection/bacterial colonization (k = 15), mortality (k = 4), and other complications (k = 18).
Key Question 4: No studies comparing one NPWT system to another NPWT system were identified by our
searches, and none were submitted by interested parties. Consequently, AHRQ were not able to
answer this Key Question. Adverse events described in the studies comparing NPWT to some
other form of wound care and in case series are described under Key Question 3.
Based on AHRQ’s defined search strategies and submissions from interested parties, no studies
directly comparing one NPWT system to another NPWT system were identified that addressed Key Questions 1, 2 or 4. Thus, AHRQ were not able to identify a significant therapeutic distinction of one NPWT system or component over another through the use of head-to-head comparisons.
This report is based on research conducted by the ECRI Institute under contract to the Agency for Healthcare Research and Quality (AHRQ), Rockville, MD (Contract No. 290-2007-10063). It may be used, in whole or in part, as the basis for development of clinical practice guidelines and other quality enhancement tools, or as a basis for reimbursement and coverage policies.