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PubMed2000

The HCV National Register: towards informing the natural history of hepatitis C infection in the UK.

The aim of this paper is to describe the development of a national hepatitis C register and the completeness of the data it contains. This is a descriptive report of the structure and function of the register, including case definitions, registration and follow-up procedures, and methods used to maximize data quality and to obtain comparative data sources. The register contains data on HCV-infected individuals who acquired their infections on a known date and by a known route; to date all are transfusion recipients identified during the UK lookback exercise, who tested positive or indeterminate for anti-HCV after receiving 'infected' blood issued before the introduction of routine testing of the blood supply for anti-HCV. By 31 December 1999, 871 (87%) of 996 eligible transfusion recipients had been registered, and 984 (99%) flagged in the NHS Central Registers. Registered patients had been infected for an average of 11.1 years (SEM 0.1); around half were being cared for by clinicians with a specialist interest in liver disease. Except for the information on tobacco use, current alcohol use, and hepatitis B status, data were more than 80% complete, and for most variables, more than 90% complete. The consistency of data abstraction was found to be 98% (SEM 0.5). In conclusion, the Register contains high quality anonymised data on one of the largest cohorts of individuals with HCV infections acquired on a known date and by a known route. It could serve as a model for other chronic disease registers; developers may find the structure, design, and methodological issues addressed useful.

Adolescent↗
PubMed1997

Policy and program analysis using administrative databases.

Administrative policies and programs play an important and growing role as determinants of the use of medical care. Although some policies and programs may be harmful or ineffectual, randomized, controlled trials or prospective evaluations are rarely done for political or logistic reasons. Most evaluations are retrospective and often use administrative databases. Major problems with such evaluations include poor data quality, lack of concurrent controls, inability to ascertain important study outcomes, and incomplete data on case mix. This article uses published evaluations to illustrate these problems and suggests strategies that can minimize their impact. Such strategies include thorough assessment of data quality, interrupted time-series or policy gradient analysis, restriction of studies to those clinical outcomes that reliably result in medical care, and use of data on medical encounters as surrogates for determining case mix. However, even when these strategies are used, adequate evaluation of the effects of many policies and programs may continue to be impossible. Prospective evaluations need to be used more frequently to ensure that changes are held to the same standard used for other therapeutic interventions.

Data Collection↗
PubMed1997

Improved R-factors for diffraction data analysis in macromolecular crystallography.

The quantity Rsym (also called Rmerge) is almost universally used for describing X-ray diffraction data quality. Here, we prove that Rsym is seriously flawed, because it has an implicit dependence on the redundance of the data. A corrected R-factor, Rmeas, is introduced as the equivalent robust indicator of data consistency. In addition, we introduce Rmrgd an R-factor that reflects the gain in accuracy upon averaging of equivalent reflections, as a useful indicator of the quality of reduced data. These new data quality indicators better reveal the benefits of highly redundant data and should stimulate improvements in data quality through increased merging of data from multiple crystals.

Crystallography, X-Ray↗
PubMed1999

Out-of-hospital violence injury surveillance: quality of data collection.

STUDY OBJECTIVE: The recognized need to improve data collection for violence prevention may be met, in part, by using out-of-hospital data for injury surveillance. The purpose of the Prehospital Violence Injury Surveillance project was to examine the extent to which paramedics can adequately collect information about injuries, particularly intentional injuries, at emergency scenes. METHODS: Paramedics in a large Midwestern metropolitan area were trained to assess violence-related events and collect relevant data using a modified ambulance run report form. Data collected from 8 violence-related training scenarios and from 13 ride-along observations were analyzed to estimate paramedic interrater reliability using the kappa statistic. Data from 7,363 run report forms, filed during a 3-month study period, were abstracted and analyzed for completeness and quality. RESULTS: Paramedics demonstrated fair to good, and sometimes excellent, interrater agreement when documenting the training scenarios. Paramedics revealed barriers to collecting violence-related out-of-hospital data. The paramedics and the observer disagreed in documenting 77% of the ride-along observations. Overall, 73% of abstracted run report forms showed documentation errors, with more than 99% of these reports containing errors of omission and 29% showing internal documentation inconsistencies. Despite the emphasis on violence-related data, documentation of domestic abuse screening was missing from more than 99% of run reports from female patients. CONCLUSION: Significant barriers to quality out-of-hospital data collection were identified during study implementation and in abstracted run reports. These barriers included the following: lack of organizational support; characteristics of the violence-related data elements; design of the ambulance run report form; and paramedic knowledge, attitudes, and behaviors regarding data collection.

Adult↗
PubMed1988

Assessing the quality of data entry in a computerized medical records system.

A primary care university clinic discovered major errors in its medical records after instituting a computerized medical records system. A quality assessment tool was devised to measure the error rate and provide clues to the sources of these errors. During the implementation of this tool a marked reduction in data entry errors occurred suggesting its use had a positive impact on our medical record quality.

Arizona↗
PubMed2005

Clearing the air: a model for investigating indoor air quality in Texas schools.

This pilot project focused on the assessment of indoor air quality at a local high school in Galveston, Texas, using methods based on guidelines for the U.S. Environmental Protection Agency's Indoor Air Quality Tools for Schools program. Tools for Schools, developed for evaluating and ensuring acceptable air quality for schools, takes a low-cost, minimal-involvement, primarily educational approach. The authors also compared the findings from this approach with the results of an air-sampling program. The overall goal was to determine if use of Tools for Schools was sufficient to identify conditions with the potential to cause adverse health effects. The primary objectives were to 1) establish an indoor air quality committee for the school to implement Tools for Schools assessments and management strategies, 2) collect air quality data in high-risk areas identified within the school by the indoor air quality committee, 3) collect outdoor air quality data at or in close proximity to the school, and 4) develop methods and instruments for assessing environmental risks associated with daily school attendance. Data were gathered on levels of formaldehyde and other volatile organic compounds (VOCs), ozone, particulate matter (PM10), mold, relative humidity, and temperature. Data values for each sampled pollutant were compared with federal standards, recommended values established by the American Conference of Governmental Industrial Hygienists for non-industrial populations, and effects screening levels developed by the Texas Commission on Environmental Quality. Levels of all VOCs except formaldehyde were found to be well within guidelines, as were ozone and particulate-matter levels. Mold, however, was widespread, including both common species and species associated with allergy and asthma, such as Aspergillus and Alternaria. In general, Tools for Schools provides an excellent foundation for a school indoor air quality program, although the authors did find it necessary to streamline data collection and did find that mold with the potential for adverse health effects was present, albeit not visible in some areas.

Air Pollutants↗
PubMed1995

A comparison of various methods of collecting self-reported health outcomes data among low-income and minority patients.

In a randomized trial of different data collection methods, we challenged the untested assumption that reliable data cannot be obtained from lower-income and/or minority patients by self-administered questionnaires. We tested three methods of data collection among a sample of lower-income and minority patients (n = 697) in Indianapolis at a site for the Type II Diabetes Patient Outcomes Research Team. The study included a questionnaire literacy screening instrument to assess patients' functional literacy. Based on their functional literacy, patients were randomized to one of three methods of data collection: mail-out/mail-back, hand-out/assisted, or the in-home interview. We constructed a tiered system for reassigning nonresponders to alternative methods of data collection, using the in-home interview as the fall-back strategy. We compared the response rates, item completion rates, and internal consistency reliabilities of self-reported health status measures between patients with and without literacy limitations and across the three methods of data collection. Patients with and without literacy limitations, across methods of data collection, provided high-quality data, as evidenced by high item completion rates (> 84%) and high reliability assessments (internal consistency reliability coefficients > .80) for each health status measure. As part of the tiered study design, nonresponders randomized to either the mail-out/mail-back or the hand-out/assisted method were interviewed. These patients were significantly older, had significantly lower education and income levels, and had significantly poorer self-reported visual function as compared with those who responded to the originally assigned method. We conclude that expensive, labor-intensive data collection methods, such as in-home interviews, are not necessary for many low-income, minority patients to generate high-quality, reliable health status data. Using appropriate screening instruments, those patient subgroups needing special help can be screening instruments, those patient subgroups needing special help can be identified and targeted for more expensive data collection methods. This tiered approach has policy implications for the cost, feasibility, and quality of data collection in health outcomes research.

Aged↗
PubMed1993

Verifying keyed medical research data.

Although diminished use of double keying for the verification of keyed medical research data has occurred, there are no published data that demonstrate the existence of equivalent or better replacement. The simple replacement of double keying with visual comparison is not recommended because visual comparison is too susceptible to the transient energy levels of the individual who makes the comparison. Some system design innovations applicable in specific situations allow elimination of verification by providing nearly equivalent or possibly even superior data quality assurance opportunities. These alternatives include designs where one replaces the transcription to data forms by direct keying from original source documents coupled with extensive quality reviews, and designs with direct data base input of data subjected to intense automated consistency checking and immediate analytic use. In both cases, the absence of keyed data verification places a greater burden for data quality assurance on other subsystems, such as quality review, and ultimately the analytic process. Data entry systems based on new technologies, such as tablet computers, electronic image processing, and voice input, will require similar considerations for assuring data quality.

Clinical Trials as Topic↗
PubMed2002

Comparative evaluation of different modes of a national accident and emergency department-based injury surveillance system: Jamaican experience.

The objective was to conduct a comparative evaluation of two injury surveillance systems in operation in the Accident and Emergency departments of public hospitals in Jamaica. The evaluation was conducted at 12 hospitals across Jamaica offering varying levels of service delivery. It was designed in three phases: (1) a retrospective review of surveillance system data; (2) prospective process evaluation; (3) system environment evaluation. These data were analysed to determine the sensitivity and specificity of the manual Accident & Emergency Statistical Report (A&ESR) versus the computer-based Patient administration system/Jamaica injury surveillance system (PAS/JISS), and to determine an injury registration rate. Results showed a variation from 8% to 27% in injury registration rates at the hospitals reviewed. The sensitivity of the computer-based PAS ranged from 29.7% to 97.1% while the sensitivity of the manual system ranged from 22.1% to 100%. The computer-based system generally detected a greater percentage of injuries. Problems were identified with missing data fields in the computer-based system, while problems of recording and transcription were identified in the manually-based system. Recommendations were made to improve data quality in both data collection systems. Although shortcomings were identified with the A&ESR, the system is performing the function for which it was designed, that of tracking A&E workload. The PAS/JISS is more user-friendly and a truer reflection of the injury situation.

Emergency Service, Hospital↗
PubMed2006

Improved plausibility bounds about the 2005 HIV and AIDS estimates.

BACKGROUND: Since 1998 the Joint United Nations Programme on HIV/AIDS and the World Health Organization has provided estimates on the magnitude of the HIV epidemic for individual countries. Starting with the 2003 estimates, plausibility bounds about the estimates were also reported. The bounds are intended to serve as a guide as to what reasonable or plausible ranges are for the uncertainty in HIV incidence, prevalence, and mortality. METHODS: Plausibility bounds were developed for three situations: for countries with generalised epidemics, for countries with low level or concentrated epidemics (LLC), and for regions. The techniques used build on those developed for the previous reporting round. However the current bounds are based on the available surveillance and survey data from each individual country rather than on data from a few prototypical countries. RESULTS: The uncertainty around the HIV estimates depends on the quality of the surveillance system in the country. Countries with population based HIV seroprevalence surveys have the tightest plausibility bounds (average relative range about the adult HIV prevalence (ARR) of -18% to +19%.) Generalised epidemic countries without a survey have the next tightest ranges (average ARR of -46% to +59%). Those LLC countries which have conducted multiple surveys over time for HIV among the populations most at risk have the bounds similar to those in generalised epidemic countries (ARR -40% to +67%). As the number and quality of the studies in LLC countries goes down, the plausibility bounds increase (ARR of -38% to +102% for countries with medium quality data and ARR of -53% to +183% for countries with poor quality data). The plausibility bounds for regions directly reflect the bounds for the countries in those regions. CONCLUSIONS: Although scientific, the plausibility bounds do not represent and should not be interpreted as formal statistical confidence intervals. However in order to make the bounds as meaningful as possible the authors have tried to apply reasonable statistical approaches and assumptions to their derivation. An understanding of the uncertainty in the HIV estimates may help policy makers take better informed decisions to address the epidemic in their respective countries.

Adolescent↗
PubMed1999

Atomic resolution structures of the core domain of avian sarcoma virus integrase and its D64N mutant.

Six crystal structures of the core domain of integrase (IN) from avian sarcoma virus (ASV) and its active-site derivative containing an Asp64 --> Asn substitution have been solved at atomic resolution ranging 1.02-1.42 A. The high-quality data provide new structural information about the active site of the enzyme and clarify previous inconsistencies in the description of this fragment. The very high resolution of the data and excellent quality of the refined models explain the dynamic properties of IN and the multiple conformations of its disordered residues. They also allow an accurate description of the solvent structure and help to locate other molecules bound to the enzyme. A detailed analysis of the flexible active-site region, in particular the loop formed by residues 144-154, suggests conformational changes which may be associated with substrate binding and enzymatic activity. The pH-dependent conformational changes of the active-site loop correlates with the pH vs activity profile observed for ASV IN.

Amino Acid Substitution↗
PubMed1986

The incorporation of red blood cell index mean data into quality control programs.

Patient red blood cell (RBC) index means, when used in quality control, form an independent standard that is as accurate and precise as preserved blood controls. If such patient data are routinely incorporated in intralaboratory and interlaboratory quality control programs, a substantial improvement in the present state-of-the-art is possible. Within the laboratory, each method serves to confirm the adequacy of the other. In interlaboratory control trials the combination makes it possible to specify the cause of most misanalyses. For similar reasons, the combination of both methods enables the manufacturer of quality control material to assess the adequacy of the manufacturing and value assignation process.

Blood Preservation↗
PubMed2003

Mutual acceptance of data: harmonised test methods and quality assurance of data--the process explained.

An essential aspect of the OECD is that it should not be considered a supranational organisation, but rather a center for discussion where governments express their points of view, share their experiences and search for common ground. This implies that decisions are made by consensus instead of majority. Once the Council, which is the highest authority of the OECD, adopts a formal Decision, such a decision is binding on all Member countries. The OECD Guidelines for the Testing of Chemicals, which are considered the leading international standard for safety testing, form an integrated part of such a binding Council Decision. An even more important part of that same Council Decision is that on Mutual Acceptance of Data, where it states that: 'Data generated in the testing of chemicals in an OECD Member country in accordance with OECD Test Guidelines and OECD Principles of Good Laboratory Practice (GLP) shall be accepted in other Member countries for purposes of assessment and other use relating to the protection of man and the environment.' In the various steps of the process of Test Guideline development, the National Co-ordinators of the Test Guideline Programme play an important role. The initiative to start the development of a particular guideline can be taken by the OECD Secretariat, by one or more Member countries or, most importantly, by the scientific community itself. Proposals, received by the Secretariat are discussed at the yearly Meeting of the National Co-ordinators. During these meetings, priorities for future activities are set and the approach that should be followed in dealing with the selected activities is discussed. Quite often, so-called Detailed Review Papers (DRP's) form the basis of a new or updated Guideline. These DRP's, which are either prepared by a Member country or by a consultant appointed by the Secretariat, describe the current 'state of the art' in scientific progress and technical possibilities of a well-defined area of research. After completion, either an expert meeting or a commenting round will be organised. All Member countries will have sufficient possibilities to express their views. When the DRP is acceptable to the experts of all Member countries, the next step is to actually develop a Test Guideline. Similar to the procedure followed for the DRP, the Test Guideline proposal will be circulated for comment to all Member countries and should reach the desks of relevant experts, nominated by their National Co-ordinator. Frequently, in addition to the commenting rounds, Test Guideline proposals are discussed in special expert meetings. Once the experts reach consensus on a particular Test Guideline, the proposal is put forward to the Meeting of the National Co-ordinators for approval. Since each guideline will form an integrated part of the earlier mentioned Council Decision, each new guideline also needs formal adoption by the Council before it becomes effective.

Animals↗
PubMed1982

Glucose stability in lyophilized chemistry quality control serum. A study of data from the quality assurance service (QAS) program of the College of American Pathologists.

Data from 2.5 million glucose analyses on pools of lyophilized human quality control serum were used to evaluate analyte stability in the prereconstitution phase. Input information was from laboratories in Regional Quality Control Programs that use CAP Quality Assurance Service (QAS) data processing. Of 31 pools in use between 1977 and 1981, decreasing glucose concentration was detected by, at least, one method in 26 pools, and by two or more methods in 21 pools. Method-associated average decrease in concentration varied from 0.13 mg/dL/month (glucose oxidase-electrode) to 0.19 mg/dL/month (automated glucose oxidase-colorimetric). Bidirectional instability as a function of analytic method, i.e., increase with "mild" methods, decrease with "rigorous" methods that was noticed previously with pools analyzed between 1973 and 1977, was no longer seen. Dominant directional changes in the later pools were downward by all methods, when statistically significant trends were demonstrated.

Blood Glucose↗
PubMed2005

Psychometric evaluation of the multiple sclerosis impact scale (MSIS-29) for proxy use.

BACKGROUND: There may be difficulties in the use of self report measurements in patients with cognitive impairment or serious mood disturbances which interfere with reliable self assessment, as may be the case in multiple sclerosis (MS). In such cases proxies may provide valuable information. However, before using any questionnaires in a proxy sample, the questionnaire should be evaluated for proxy use. OBJECTIVE: To evaluate the psychometric properties of the 29 item Multiple Sclerosis Impact Scale (MSIS-29) when used by proxies of MS patients. METHODS: A sample of 62 partners of MS patients completed the MSIS-29. The data were evaluated for the psychometric criteria of the MSIS-29, including data quality, scaling assumptions, acceptability, reliability, validity, and responsiveness. RESULTS: Psychometric evaluation was satisfactory; data quality was high, and scaling assumptions and acceptability were good. Reliability was high (alpha>0.80). Findings were consistent with results of a psychometric evaluation in a patient sample. CONCLUSIONS: The MSIS-29 can be used reliably in proxies of patients with MS. As a next step the relation between data obtained from patients and proxies needs to be studied, focusing on factors that may affect agreement and discrepancies.

Adult↗
PubMed2002

Cleavage stage versus blastocyst stage embryo transfer in assisted conception.

BACKGROUND: Despite numerous advances in the field of in vitro fertilisation (IVF), many of the widely applied embryo culture techniques and resulting implantation rates have remained relatively unchanged since the first treatment was performed in the mid 1970's. Recent advances in the understanding of nutrient requirements of embryos, have led to a renaissance of extending their culture from the standard procedure of 2-3 days (early cleavage embryo transfer) to 5-6 days (blastocyst culture). The rationale for blastocyst culture is to improve the synchronicity of uterine and embryonic development and provide a mechanism for self-selection of viable embryos. Numerous reports on the clinical benefits of blastocyst culture have led to the worldwide introduction of this technique, despite a deficiency of conclusive evidence to do so. OBJECTIVES: Primary: To determine if blastocyst stage embryo transfers (ET's) result in higher success rates, than cleavage stage embryo transfers. Secondary: To assess the overall embryo utilisation rate of both techniques. SEARCH STRATEGY: Electronic searches of the Cochrane Menstrual Disorders and Subfertility Group specialised register of controlled trials, CCTR, MEDLINE, EMBASE, and Bio extracts were performed to identify relevant randomised controlled trials (RCTs). Attempts were also made to identify trials from the National Research Register, the Clinical Trial Register and the citation lists of review articles and included trials. The first or corresponding author of each included trial was also contacted for additional information. SELECTION CRITERIA: Trials were included if they were randomised and compared the effectiveness of early cleavage versus blastocyst stage transfers. DATA COLLECTION AND ANALYSIS: Of the 29 trials that were identified, ten trials met the inclusion criteria and were reviewed. Primary outcomes were rates of; live birth, clinical pregnancy and implantation per woman. Secondary outcomes were rates of; miscarriage, monozygotic twinning, embryo freezing, embryo utilisation, cancellation, multiple pregnancy and high order pregnancy and per cycle data. Quality assessment and data extraction were performed independently by two reviewers. Meta analysis was performed using odds ratios for dichotomous outcomes and weighted mean differences for continuous outcomes. MAIN RESULTS: There was no significant difference between the two treatment groups in live birth rate, although this was reported by only one quasi-random trial (Peto OR 1.59, 95% CI 0.80, 3.15). There was also no evidence of a difference in pregnancy rate (both overall and subgroups) between the two groups for pregnancy rate per couple randomised (4 RCTs: Peto OR 0.86, 95% CI 0.57, 1.29). There was also no suggestion of an overall difference in implantation rates per embryo's transferred although it was impossible to calculate valid confidence intervals from published data (Day 2/3 17.1% vs Day 5/6 18.9%). The subgroup of sequential media trials suggested higher implantation rate for blastocyst transfer (Day 2/3 22.6% vs Day 5/6 32%). The miscarriage rate was no different between the two groups (1 RCT, Peto OR 1.66, 95% CI 0.41, 6.81). The RCTs reporting embryo freezing showed no difference (Peto OR 1.71, 95% CI 1.00, 2.94), however the two quasi-random trials showed a significant difference in favour of the Day 2/3 group (Peto OR 2.99, 95% CI 1.88, 4.75). Embryo transfer cancellation rates were significantly higher in the Day 5/6 group (5 RCTs: Peto OR 0.57, 95% CI 0.40, 0.83). There was no significant difference in the rate of multiple pregnancies or the rate of high order pregnancies (3 RCTs, Peto OR 0.58, 95% CI 0.30, 1.12)(2 RCTs, Peto OR 7.88, 95% CI 0.49, 126.30 respectively). REVIEWER'S CONCLUSIONS: Overall this review of the best available evidence based on data from randomised controlled trials, suggests that to date little difference in the major outcome parameters has been demonstrated between early embryo transfer and blastocyst culture. Collectively, the increase in cancellation and the possible decrease in cryopreservation rates suggest that the routine practice of blastocyst culture should be offered to patients with caution. The subgroup of trials employing sequential media, did however demonstrate a substantial improvement in implantation rates and similar pregnancy rates, despite the transfer of less embryos. Whether this trend will culminate in convincing higher live birth rates per woman, has yet to be validated.

Blastocyst↗
PubMed2005

Cleavage stage versus blastocyst stage embryo transfer in assisted conception.

BACKGROUND: In the past decade, advances in the understanding of nutrient requirements of embryos, has led to the evolution of culture media designed to support extended culture of embryos in vitro from the standard procedure of 2 to 3 days (for early cleavage embryo transfer) to 5 to 6 days (blastocyst culture). The rationale for blastocyst culture is to improve the synchronicity of uterine and embryonic development and provide a mechanism for self-selection of viable embryos. Since the initial widespread introduction of blastocyst culture in 1998, there has been conflicting reports about the clinical benefits of this technique. OBJECTIVES: To determine if blastocyst stage embryo transfers (ETs) affects success rates compared with cleavage stage ETs and investigate what factors may influence this. SEARCH STRATEGY: We searched the Cochrane Menstrual Disorders and Subfertility Group Specialised Register of controlled trials. We also searched the Cochrane Controlled Trials Register (CENTRAL) (The Cochrane Library), MEDLINE, EMBASE and Bio extracts. Attempts were made to identify trials from the National Research Register, the Clinical Trials Register and the citation lists of review articles and included trials. The last search date was May 2005. The first or corresponding author of each included trial was contacted for additional information. SELECTION CRITERIA: Trials were included if they were randomised and compared the effectiveness of early cleavage versus blastocyst stage transfers. DATA COLLECTION AND ANALYSIS: Of the 45 trials that were identified, 16 trials met the inclusion criteria and were reviewed. Primary outcomes were rates of live birth, clinical pregnancy and multiple-pregnancy rates per couple. Secondary outcomes were rates of miscarriage, failure to transfer embryos, freezing, implantation and high order pregnancy and per cycle data. Quality assessment and data extraction were performed independently by two review authors. Meta-analysis was performed using odds ratios (OR) for dichotomous outcomes and weighted mean differences for binary outcomes with 95% confidence intervals (CI). MAIN RESULTS: There was no evidence of a difference in live-birth rate per couple between the two treatment groups (7 RCTs; OR 1.16, 95% CI 0.74 to 1.44 [Day 2/3 34.3% vs. Day 5/6 35.4%]); in the clinical pregnancy rate per couple (15 RCTs; OR 1.05, 95% CI 0.88 to 1.26 [Day 2/3 38.8% vs. 40.3%]) even for good prognosis patients (6 RCTs: OR 96% 1.06 CI 0.83 to 1.34). There was also no difference in multiple-pregnancy rate per couple (12 RCTs; OR 0.85, 95% CI 0.63 to 1.13) particularly in trials where equal numbers of embryos were transferred in both groups (6 RCTs: OR 0.91, 95% CI 0.63 to 1.32). There was no evidence of a difference in high order multiple-pregnancy rates per couple (5 RCTs; OR 0.44, 95% CI 0.15 to 1.33) or miscarriage rate per couple between the two groups (9 RCTs; OR 1.33, 95% CI 0.89 to 2.01). Rates of embryo freezing per couple was significantly higher in Day 2 to 3 transfers (9 RCTs; OR 0.45, 95% CI 0.36 to 0.57). Failure to transfer any embryos per couple was significantly higher in the Day 5 to 6 group (10 RCTs: OR 3.21, 95% CI 2.15 to 4.81[Day 2/3 3.5% vs D 5/6 10.1%]), but was not significantly different for good prognosis patients (7RCTs, OR 1.58 95% CI 0.65 to 3.82). AUTHORS' CONCLUSIONS: There is no evidence of a difference in live birth or pregnancy outcomes between Day 2 to 3 and Day 5 to 6 transfer of embryos. Blastocyst transfer was associated with an increase in failure to transfer any embryos in a cycle and a decrease in embryo freezing rates. In the absence of data on cumulative live birth rates resulting from fresh and thawed cycles, it is not possible to determine if this represents an advantage or disadvantage.

Blastocyst↗