A Systematic Literature Review of Predictors of Erythropoiesis-Stimulating Agent Failure in Lower-Risk Myelodysplastic Syndromes.

Erythropoiesis-stimulating agents (ESAs) are the first-line treatment option for anemia in patients with lower-risk myelodysplastic syndromes (LR-MDS). A systematic literature review was conducted to identify evidence of the association between prognostic factors and ESA response/failure in LR-MDS. MEDLINE, Embase, and relevant conferences were searched systematically for studies assessing the association between prognostic factors and ESA response/failure in adult patients. Of 1566 citations identified, 38 were included. Patient risk status in studies published from 2000 onwards was commonly assessed using the International Prognostic Scoring System (IPSS) or revised IPSS. ESA response was generally assessed using the International Working Group MDS criteria. Among the included studies, statistically significant relationships were found, in both univariate and multivariate analyses, between ESA response and the following prognostic factors: higher hemoglobin levels, lower serum erythropoietin levels, and transfusion independence. Furthermore, other prognostic factors such as age, bone marrow blasts, serum ferritin level, IPSS risk status, and karyotype status did not demonstrate statistically significant relationships with ESA response. This systematic literature review has confirmed prognostic factors of ESA response/failure. Guidance to correctly identify patients with these characteristics could be helpful for clinicians to provide optimal treatment.

A Systematic Literature Review of the Relationship between Serum Ferritin and Outcomes in Myelodysplastic Syndromes.

Anemia is the most common form of cytopenia in patients with myelodysplastic syndromes (MDS), who require chronic red blood cell transfusions and may present high serum ferritin (SF) levels as a result of iron overload. To better understand the potential effects of high SF levels, we conducted a systematic literature review (SLR) to identify evidence on the relationship between SF levels and clinical, economic, or humanistic outcomes in adult patients with MDS. Of 267 references identified, 21 were included. No studies assessing SF levels and their relationship with humanistic or economic outcomes were identified. Increased SF levels were an indicator of worse overall survival and other worsened outcomes; however, the association was not consistently significant. SF levels were a significant prognostic factor for relapse incidence of MDS and showed a significant positive correlation with number of blood units transfused but were not associated with progression to acute myeloid leukemia or the time to transformation. Higher SF levels were also an indicator of a lower likelihood of leukemia-free survival, relapse-free survival, and event-free survival. The SLR suggests that SF levels are associated with clinical outcomes in MDS, with higher levels correlated with number of blood units transfused, frequently indicating worse outcomes.

Clinical evidence for the first-line treatment of advanced urothelial carcinoma: Current paradigms and emerging treatment options.

BACKGROUND: Patients with advanced urothelial carcinoma (UC) have poor outcomes, with 5-year survival rates of <5% for those with metastatic, stage IV disease. We have reviewed current treatment paradigms and emerging treatment options for these patients. METHODS: The websites of seven national or international organizations were searched for metastatic UC treatment guidelines. Systematic literature reviews were conducted to identify evidence from randomized controlled trials (RCTs) of chemotherapy for patients with previously untreated, unresectable, stage IV UC. Searches included congress databases and articles published between 1990 and 2018. In order to align with the latest treatment paradigms in first-line advanced UC, a focused literature search was conducted to identify evidence supporting immuno-oncology (IO) agents. RESULTS: For advanced UC, guidelines universally recommend cisplatin-based chemotherapy as first-line treatment for eligible patients and carboplatin-based regimens for those unfit to receive cisplatin. Despite the evaluation of a number of different cytotoxic regimens over the years, including triplet combinations, survival outcomes have not improved markedly with chemotherapy. Median overall survival with standard of care chemotherapy is ~13 months. Based on the results of single-arm, phase II studies, recent treatment guidelines have included atezolizumab (anti-PD-L1) and pembrolizumab (anti-PD-1) as first-line options for cisplatin-ineligible patients whose tumors express high levels of PD-L1. However, emerging evidence from RCTs of IO agents, including both cisplatin-eligible and cisplatin-ineligible patients, suggest that survival times exceeding 20 months are possible. CONCLUSIONS: After having reached a plateau with chemotherapy, the treatment landscape for advanced UC is evolving. Survival outcomes for patients with advanced UC are improving with treatment modalities involving IO agents.

Does deep neuromuscular blockade during laparoscopy procedures change patient, surgical, and healthcare resource outcomes? A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Deep neuromuscular blockade may facilitate the use of reduced insufflation pressure without compromising the surgical field of vision. The current evidence, which suggests improved surgical conditions compared with other levels of block during laparoscopic surgery, features significant heterogeneity. We examined surgical patient- and healthcare resource use-related outcomes of deep neuromuscular blockade compared with moderate neuromuscular blockade in adults undergoing laparoscopic surgery. METHODS: We conducted a systematic literature review according to the quality standards recommended by the Cochrane Handbook for Systematic Reviews. Randomized controlled trials comparing outcomes of deep neuromuscular blockade and moderate neuromuscular blockade among adults undergoing laparoscopic surgeries were included. A random-effects model was used to conduct pair-wise meta-analyses. RESULTS: The systematic literature review included 15 studies-only 13 were analyzable in the meta-analysis and none were judged to be at high risk of bias. Compared with moderate neuromuscular blockade, deep neuromuscular blockade was associated with improved surgical field of vision and higher vision quality scores. Also, deep neuromuscular blockade was associated with a reduction in the post-operative pain scores in the post-anesthesia care unit compared with moderate neuromuscular blockade, and there was no need for an increase in intra-abdominal pressure during the surgical procedures. There were minor savings on resource utilization, but no differences were seen in recovery in the post-anesthesia care unit or overall length of hospital stay with deep neuromuscular blockade. CONCLUSIONS: Deep neuromuscular blockade may aid the patient and physician surgical experience by improving certain patient outcomes, such as post-operative pain and improved surgical ratings, compared with moderate neuromuscular blockade. Heterogeneity in the pooled estimates suggests the need for better designed randomized controlled trials.

The impact of intra-abdominal pressure on perioperative outcomes in laparoscopic cholecystectomy: a systematic review and network meta-analysis of randomized controlled trials.

BACKGROUND: Laparoscopic cholecystectomy involves using intra-abdominal pressure (IAP) to facilitate adequate surgical conditions. However, there is no consensus on optimal IAP levels to improve surgical outcomes. Therefore, we conducted a systematic literature review (SLR) to examine outcomes of low, standard, and high IAP among adults undergoing laparoscopic cholecystectomy. METHODS: An electronic database search was performed to identify randomized controlled trials (RCTs) that compared outcomes of low, standard, and high IAP among adults undergoing laparoscopic cholecystectomy. A Bayesian network meta-analysis (NMA) was used to conduct pairwise meta-analyses and indirect treatment comparisons of the levels of IAP assessed across trials. RESULTS: The SLR and NMA included 22 studies. Compared with standard IAP, on a scale of 0 (no pain at all) to 10 (worst imaginable pain), low IAP was associated with significantly lower overall pain scores at 24 h (mean difference [MD]: - 0.70; 95% credible interval [CrI]: - 1.26, - 0.13) and reduced risk of shoulder pain 24 h (odds ratio [OR] 0.24; 95% CrI 0.12, 0.48) and 72 h post-surgery (OR 0.22; 95% CrI 0.07, 0.65). Hospital stay was shorter with low IAP (MD: - 0.14 days; 95% CrI - 0.30, - 0.01). High IAP was not associated with a significant difference for these outcomes when compared with standard or low IAP. No significant differences were found between the IAP levels regarding need for conversion to open surgery; post-operative acute bleeding, pain at 72 h, nausea, and vomiting; and duration of surgery. CONCLUSIONS: Our study of published trials indicates that using low, as opposed to standard, IAP during laparoscopic cholecystectomy may reduce patients' post-operative pain, including shoulder pain, and length of hospital stay. Heterogeneity in the pooled estimates and high risk of bias of the included trials suggest the need for high-quality, adequately powered RCTs to confirm these findings.

Clinically inappropriate post hoc exclusion of study participants from test accuracy calculations: the ROMA score, an example from a recent NICE diagnostic assessment.

OBJECTIVE: To explore how the definition of the target condition and post hoc exclusion of participants can limit the usefulness of diagnostic accuracy studies. METHODS: We used data from a systematic review, conducted for a NICE diagnostic assessment of risk scores to inform secondary care decisions about specialist referral for women with suspected ovarian cancer, to explore how the definition of the target condition and post hoc exclusion of participants can limit the usefulness of diagnostic accuracy studies to inform clinical practice. RESULTS: Fourteen of the studies evaluated the ROMA score, nine used Abbott ARCHITECT tumour marker assays, five used Roche Elecsys. The summary sensitivity estimate (Abbott ARCHITECT) was highest, 95.1% (95% CI: 92.4 to 97.1%), where analyses excluded participants with borderline tumours or malignancies other than epithelial ovarian cancer and lowest, 75.0% (95% CI: 60.4 to 86.4%), where all participants were included. Results were similar for Roche Elecsys tumour marker assays. Although the number of patients involved was small, data from studies that reported diagnostic accuracy for both the whole study population and with post hoc exclusion of those with borderline or non-epithelial malignancies suggested that patients with borderline or malignancies other than epithelial ovarian cancer accounts for between 50 and 85% of false-negative ROMA scores. CONCLUSIONS: Our results illustrate the potential consequences of inappropriate population selection in diagnostic studies; women with non-epithelial ovarian cancers or non-ovarian primaries, and those borderline tumours may be disproportionately represented among those with false negative, 'low risk' ROMA scores. These observations highlight the importance of giving careful consideration to how the target condition has been defined when assessing whether the diagnostic accuracy estimates reported in clinical studies will translate into clinical utility in real-world settings.

Arsenic Trioxide for Treating Acute Promyelocytic Leukaemia: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

The National Institute for Health and Care Excellence (NICE) invited Teva, the company manufacturing arsenic trioxide (ATO; tradename Trisenox®), to submit evidence for the clinical and cost effectiveness of ATO for untreated and relapsed or refractory acute promyelocytic leukaemia (APL). Kleijnen Systematic Reviews Ltd (KSR), in collaboration with Maastricht University Medical Center, was commissioned as the independent Evidence Review Group (ERG). This paper presents a summary of the company submission (CS), the ERG's critical review of the clinical and cost effectiveness evidence in the CS, key methodological considerations and the development of the NICE guidance by the Appraisal Committee (AC). The CS presented three randomized controlled trials (RCTs). Two of these were trials in newly diagnosed APL (APL0406 and AML17) and the third trial was in patients with relapsed APL. Results from APL0406 showed that more people having AATO [ATO plus all-trans retinoic acid (ATRA)] were alive at 50 months compared with people having AIDA (ATRA in combination with idarubicin) (99% vs. 93%; p = 0.007). There was also a statistically significant lower cumulative incidence of relapse with AATO compared with AIDA at 50 months (2% vs. 14%; p = 0.001). At 4 years, results from AML17 showed a significant difference in event-free survival (91% vs. 70%; p = 0.002) favouring AATO but not in overall survival (93% vs. 89%; p = 0.250). The only trial presented for relapsed/refractory patients compared AATO with ATO, which was not a relevant comparison according to the NICE scope. The AC concluded that AATO was effective for untreated APL while for relapsed or refractory APL the effectiveness of ATO was considered uncertain and the long-term safety remains unexplored. In the CS base-case, AATO was less expensive (£31,088 saved) and more effective (2.546 quality-adjusted life-years (QALYs) gained) than AIDA and thus the dominating strategy for newly diagnosed low- to intermediate-risk APL. However, the ERG's critical assessment highlighted a number of concerns, including deviations from the NICE reference case and a lack of detailed description and justification of parameters and assumptions related to (the extrapolation of) treatment effectiveness. However, it was reassuring that AATO for untreated APL remained dominant in the ERG base-case, and that the worst-case scenario produced by the ERG resulted in an incremental cost-effectiveness ratio (ICER) of £21,622. The AC concluded that although there was uncertainty in the model, it could recommend ATO for both untreated and relapsed or refractory APL.

Risk scores to guide referral decisions for people with suspected ovarian cancer in secondary care: a systematic review and cost-effectiveness analysis.

BACKGROUND: Ovarian cancer is the sixth most common cancer in UK women and can be difficult to diagnose, particularly in the early stages. Risk-scoring can help to guide referral to specialist centres. OBJECTIVES: To assess the clinical and cost-effectiveness of risk scores to guide referral decisions for women with suspected ovarian cancer in secondary care. METHODS: Twenty-one databases, including MEDLINE and EMBASE, were searched from inception to November 2016. Review methods followed published guidelines. The meta-analysis using weighted averages and random-effects modelling was used to estimate summary sensitivity and specificity with 95% confidence intervals (CIs). The cost-effectiveness analysis considered the long-term costs and quality-adjusted life-years (QALYs) associated with different risk-scoring methods, and subsequent care pathways. Modelling comprised a decision tree and a Markov model. The decision tree was used to model short-term outcomes and the Markov model was used to estimate the long-term costs and QALYs associated with treatment and progression. RESULTS: Fifty-one diagnostic cohort studies were included in the systematic review. The Risk of Ovarian Malignancy Algorithm (ROMA) score did not offer any advantage over the Risk of Malignancy Index 1 (RMI 1). Patients with borderline tumours or non-ovarian primaries appeared to account for disproportionately high numbers of false-negative, low-risk ROMA scores. (Confidential information has been removed.) To achieve similar levels of sensitivity to the Assessment of Different NEoplasias in the adneXa (ADNEX) model and the International Ovarian Tumour Analysis (IOTA) group's simple ultrasound rules, a very low RMI 1 decision threshold (25) would be needed; the summary sensitivity and specificity estimates for the RMI 1 at this threshold were 94.9% (95% CI 91.5% to 97.2%) and 51.1% (95% CI 47.0% to 55.2%), respectively. In the base-case analysis, RMI 1 (threshold of 250) was the least effective [16.926 life-years (LYs), 13.820 QALYs] and the second cheapest (£5669). The IOTA group's simple ultrasound rules (inconclusive, assumed to be malignant) were the cheapest (£5667) and the second most effective [16.954 LYs, 13.841 QALYs], dominating RMI 1. The ADNEX model (threshold of 10%), costing £5699, was the most effective (16.957 LYs, 13.843 QALYs), and compared with the IOTA group's simple ultrasound rules, resulted in an incremental cost-effectiveness ratio of £15,304 per QALY gained. At thresholds of up to £15,304 per QALY gained, the IOTA group's simple ultrasound rules are cost-effective; the ADNEX model (threshold of 10%) is cost-effective for higher thresholds. LIMITATIONS: Information on the downstream clinical consequences of risk-scoring was limited. CONCLUSIONS: Both the ADNEX model and the IOTA group's simple ultrasound rules may offer increased sensitivity relative to current practice (RMI 1); that is, more women with malignant tumours would be referred to a specialist multidisciplinary team, although more women with benign tumours would also be referred. The cost-effectiveness model supports prioritisation of sensitivity over specificity. Further research is needed on the clinical consequences of risk-scoring. STUDY REGISTRATION: This study is registered as PROSPERO CRD42016053326. FUNDING DETAILS: The National Institute for Health Research Health Technology Assessment programme.

A systematic literature review comparing methods for the measurement of patient persistence and adherence.

OBJECTIVES: A systematic literature review was conducted comparing different approaches estimating persistence and adherence in chronic diseases with polypharmacy of oral and subcutaneous treatments. METHODS: This work followed published guidance on performing systematic reviews. Twelve electronic databases and grey literature sources were used to identify studies and guidelines for persistence and adherence of oral and subcutaneous therapies in hypercholesterolemia, type 2 diabetes, hypertension, osteoporosis and rheumatoid arthritis. Outcomes of interest of each persistence and adherence data collection and calculation method included pros: accurate, easy to use, inexpensive; and cons: inaccurate, difficult to use, expensive. RESULTS: A total of 4158 records were retrieved up to March 2017. We included 16 observational studies, 5 systematic reviews and 7 guidelines, in patients with hypercholesterolemia (n = 8), type 2 diabetes (n = 4), hypertension (n = 2), rheumatoid arthritis (n = 1) and mixed patient populations (n = 13). Pharmacy and medical records offer an accurate, easy and inexpensive data collection method. Pill count, medication event monitoring systems (MEMs), self-report questionnaires and observer report are easy to use. MEMS and biochemical monitoring tests can be expensive. Proportion of days covered (PDC) was recommended as a gold standard calculation method for long-term treatments. PDC avoids use of days' supply in calculation, hence is more accurate compared to medication possession ratio (MPR) to assess adherence to treatments in chronic diseases. CONCLUSIONS: Decisions on what method to use should be based on considerations of the route of medication administration, the resources available, setting and aim of the assessment. Combining different methods may provide wider insights into adherence and persistence, including patient behavior.

Abiraterone Acetate for the Treatment of Chemotherapy-Naïve Metastatic Castration-Resistant Prostate Cancer: An Evidence Review Group Perspective of an NICE Single Technology Appraisal.

The National Institute for Health and Care Excellence (NICE) invited Janssen, the company manufacturing abiraterone acetate (AA; tradename Zytiga®), to submit evidence for the clinical and cost effectiveness of AA in combination with prednisone/prednisolone (AAP) compared with watchful waiting (i.e. best supportive care [BSC]) for chemotherapy-naïve patients with metastatic castration-resistant prostate cancer (mCRPC). Kleijnen Systematic Reviews Ltd (KSR), in collaboration with Maastricht University Medical Center, was commissioned as the Evidence Review Group (ERG). This paper presents a summary of the company submission (CS), the ERG report, subsequent addenda, and the development of the NICE guidance for the use of this drug in England and Wales by the Appraisal Committee (AC). The ERG produced a critical review of the clinical and cost effectiveness of AAP based on the CS. An important question in this appraisal was, according to the ERG, whether AAP followed by docetaxel is more effective than BSC followed by docetaxel. In the COU-AA-302 trial, 239 of 546 (43.8 %) AAP patients and 304 of 542 (56.1 %) BSC patients received docetaxel as subsequent therapy, following AA or placebo. The results for this specific group of patients were not presented in the CS; therefore, the ERG asked the company to provide these data in the clarification letter; however, these data were presented as commercial-in-confidence and cannot therefore be reported here. The ERG's critical assessment of the company's economic evaluation highlighted a number of concerns, including (a) not using the intention-to-treat (ITT) population; (b) inconsistencies in estimating prediction equations; (c) not fully incorporating the impact of adverse events; (d) incorrectly incorporating the new patient access scheme (PAS); and (e) the assumption that AA non-compliance leads to recoverable drug costs. Although some of these issues were adjusted in the ERG base case, the ERG could not estimate the impact of all of these issues, and thus acknowledges that there are still uncertainties concerning the cost-effectiveness evidence. With the exception of the ERG's preference for using the ITT population, the AC agreed with the approach taken in the ERG base case. The original company and ERG base-case incremental cost-effectiveness ratios (ICERs) were £46,722 and £57,688 per QALY gained, respectively; these changed to £28,563 and £38,061 per QALY gained, respectively, in the revised base cases applying a new PAS. Regarding the end-of-life criteria, after 24 months approximately 63 % of patients in the control group of the COU-AA-302 trial were still alive, and the median survival was 30.1 months (95 % CI 27.3-34.1). Therefore, it is unlikely that life expectancy would be less than 24 months. The AC stated that the most plausible ICER is likely between £28,600 and £32,800 per QALY gained, and concluded that AAP at this stage in the treatment pathway did not meet the end-of-life criterion for short life expectancy. Moreover, in March 2016, the AC produced the final guidance, stating that AAP is recommended, within its marketing authorisation, as an option for treating mCRPC.

Lenalidomide for the Treatment of Low- or Intermediate-1-Risk Myelodysplastic Syndromes Associated with Deletion 5q Cytogenetic Abnormality: An Evidence Review of the NICE Submission from Celgene.

The National Institute for Health and Care Excellence (NICE) invited the manufacturer of lenalidomide (Celgene) to submit evidence of the clinical and cost effectiveness of the drug for treating adults with myelodysplastic syndromes (MDS) associated with deletion 5q cytogenetic abnormality, as part of the Institute's single technology appraisal (STA) process. Kleijnen Systematic Reviews Ltd (KSR), in collaboration with Erasmus University Rotterdam, was commissioned to act as the Evidence Review Group (ERG). This paper describes the company's submission, the ERG review, and the NICE's subsequent decisions. The ERG reviewed the evidence for clinical and cost effectiveness of the technology, as submitted by the manufacturer to the NICE. The ERG searched for relevant additional evidence and validated the manufacturer's decision analytic model to examine the robustness of the cost-effectiveness results. Clinical effectiveness was obtained from a three-arm, European, randomized, phase III trial among red blood cell (RBC) transfusion-dependent patients with low-/intermediate-1-risk del5q31 MDS. The primary endpoint was RBC independence for ≥26 weeks, and was reached by a higher proportion of patients in the lenalidomide 10 and 5 mg groups compared with placebo (56.1 and 42.6 vs 5.9 %, respectively; both p < 0.001). The option of dose adjustments after 16 weeks due to dose-limiting toxicities or lack of response made long-term effectiveness estimates unreliable, e.g. overall survival (OS). The de novo model of the manufacturer included a Markov state-transition cost-utility model implemented in Microsoft Excel. The base-case incremental cost-effectiveness ratio (ICER) of the manufacturer was £56,965. The ERG assessment indicated that the modeling structure represented the course of the disease; however, a few errors were identified and some of the input parameters were challenged. In response to the appraisal documentation, the company revised the economic model, which increased the ICER to £68,125 per quality-adjusted life-year. The NICE Appraisal Committee (AC) did not recommend lenalidomide as a cost-effective treatment. Subsequently, the manufacturer submitted a Patient Access Scheme (PAS) that provided lenalidomide free of charge for patients who remained on treatment after 26 cycles. This PAS improved the ICER to £25,300, although the AC considered the proportion of patients who received treatment beyond 26 cycles, and hence the ICER, to be uncertain. Nevertheless, the AC accepted a commitment from the manufacturer to publish, once available, data on the proportion of patients eligible for the PAS, and believed this provided reassurance that lenalidomide was a cost-effective treatment for low- or intermediate-1-risk MDS patients.

The use of fenestrated and branched endovascular aneurysm repair for juxtarenal and thoracoabdominal aneurysms: a systematic review and cost-effectiveness analysis.

BACKGROUND: Patients with large abdominal aortic aneurysms (AAAs) are usually offered reparative treatment given the high mortality risk. There is uncertainty about how to treat juxtarenal AAAs (JRAAAs) or thoracoabdominal aortic aneurysms (TAAAs). Endovascular repair of an abdominal aortic aneurysm (EVAR) is often seen as safer and easier than open surgical repair (OSR). However, endovascular treatment of JRAAAs or TAAAs requires specially manufactured stent grafts, with openings to allow blood to reach branches of the aorta. Commissioners are receiving increasing requests for fenestrated EVAR (fEVAR) and branched EVAR (bEVAR), but it is unclear whether or not the extra cost of fEVAR or bEVAR is justified by advantages for patients. OBJECTIVE(S): To assess the clinical effectiveness, safety and cost-effectiveness of fEVAR and bEVAR in comparison with conventional treatment (i.e. no surgery) or OSR for two populations: JRAAAs and TAAAs. DATA SOURCES: Resources were searched from inception to October 2013, including MEDLINE (OvidSP), EMBASE (OvidSP) and the Cochrane Central Register of Controlled Trials (Wiley) and, additionally, for cost-effectiveness, NHS Economic Evaluation Database (NHS EED; Wiley) and EconLit (EBSCOhost). Conference abstracts were also searched. REVIEW METHODS: Studies were included based on an intervention of either fEVAR or bEVAR and a comparator of either OSR or no surgery. For clinical effectiveness, observational studies were excluded only if they were not comparative, i.e. explicitly selected on the basis of prognosis. RESULTS: For clinical effectiveness, searches retrieved 5253 records before deduplication. Owing to overlap between the databases, 1985 duplicate records were removed. Of the remaining 3268 records, based on titles and abstracts, 3244 records were excluded, leaving 24 publications to be ordered. All 24 studies were excluded as none of them satisfied the inclusion criteria. Sixteen studies were excluded on study design, six on intervention and two on comparator. Five out of 16 studies excluded on study design reported a comparison. However, all of the studies acknowledged that they had groups that were not comparable at baseline given that they had selectively assigned younger, fitter patients to OSR. Therefore, these studies were considered 'non-comparative'. For cost-effectiveness, searches identified 104 references before deduplication. Owing to overlap between the databases, 34 duplicate records were removed. Of the remaining 70 records, seven were included for the full assessment based on initial screening. After a full-text review, no studies were included. Because of the lack of clinical effectiveness evidence and difficulty in estimating costs given the rapidly changing and variable technology, a cost-effectiveness analysis (CEA) was not performed. Instead a detailed description of modelling methods was provided. CONCLUSIONS: Despite a thorough search, no studies could be found that met the inclusion criteria. All studies that compared either fEVAR or bEVAR with either OSR or no surgery explicitly selected patients based on prognosis, i.e. essentially the populations for each comparator were not the same. Despite not being able to conduct a CEA, we have provided detailed methods for the conduct if data becomes available. FUTURE WORK: We recommend at least one clinical trial to provide an unbiased estimate of effect for fEVAR/bEVAR compared with OSR or no surgery. This trial should also collect data for a CEA. STUDY REGISTRATION: This study is registered as PROSPERO CRD42013006051. FUNDING: The National Institute for Health Research Health Technology Assessment programme.