Cystatin C or creatinine for pre-operative assessment of kidney function and risk of post-operative acute kidney injury: a secondary analysis of the METS cohort study.

Background: Post-operative acute kidney injury (PO-AKI) is a common surgical complication consistently associated with subsequent morbidity and mortality. Prior kidney dysfunction is a major risk factor for PO-AKI, however it is unclear whether serum creatinine, the conventional kidney function marker, is optimal in this population. Serum cystatin C is a kidney function marker less affected by body composition and might provide better prognostic information in surgical patients. Methods: This was a pre-defined, secondary analysis of a multi-centre prospective cohort study of pre-operative functional capacity. Participants were aged ≥40 years, undergoing non-cardiac surgery. We assessed the association of pre-operative estimated glomerular filtration rate (eGFR) calculated using both serum creatinine and serum cystatin C with PO-AKI within 3 days after surgery, defined by KDIGO creatinine changes. The adjusted analysis accounted for established AKI risk factors. Results: A total of 1347 participants were included (median age 65 years, interquartile range 56-71), of whom 775 (58%) were male. A total of 82/1347 (6%) patients developed PO-AKI. These patients were older, had higher prevalence of cardiovascular disease and related medication, were more likely to have intra-abdominal procedures, had more intraoperative transfusion, and were more likely to be dead at 1 year after surgery 6/82 (7.3%) vs 33/1265 (2.7%) (P = .038). Pre-operative eGFR was lower in AKI than non-AKI patients using both creatinine and cystatin C. When both measurements were considered in a single age- and sex-adjusted model, eGFR-Cysc was strongly associated with PO-AKI, with increasing risk of AKI as eGFR-Cysc decreased below 90, while eGFR-Cr was no longer significantly associated. Conclusions: Data from over 1000 prospectively recruited surgical patients confirms pre-operative kidney function as major risk factor for PO-AKI. Of the kidney function markers available, compared with creatinine, cystatin C had greater strength of association with PO-AKI and merits further assessment in pre-operative assessment of surgical risk.

Effectiveness of conservative management versus laparoscopic cholecystectomy in the prevention of recurrent symptoms and complications in adults with uncomplicated symptomatic gallstone disease (C-GALL trial): pragmatic, multicentre randomised controlled trial.

OBJECTIVE: To assess the clinical and cost effectiveness of conservative management compared with laparoscopic cholecystectomy for the prevention of symptoms and complications in adults with uncomplicated symptomatic gallstone disease. DESIGN: Parallel group, pragmatic randomised, superiority trial. SETTING: 20 secondary care centres in the UK. PARTICIPANTS: 434 adults (>18 years) with uncomplicated symptomatic gallstone disease referred to secondary care, assessed for eligibility between August 2016 and November 2019, and randomly assigned (1:1) to receive conservative management or laparoscopic cholecystectomy. INTERVENTIONS: Conservative management or surgical removal of the gallbladder. MAIN OUTCOME MEASURES: The primary patient outcome was quality of life, measured by area under the curve, over 18 months using the short form 36 (SF-36) bodily pain domain, with higher scores (range 0-100) indicating better quality of life. Other outcomes included costs to the NHS, quality adjusted life years (QALYs), and incremental cost effectiveness ratio. RESULTS: Of 2667 patients assessed for eligibility, 434 were randomised: 217 to the conservative management group and 217 to the laparoscopic cholecystectomy group. By 18 months, 54 (25%) participants in the conservative management arm and 146 (67%) in the cholecystectomy arm had received surgery. The mean SF-36 norm based bodily pain score was 49.4 (standard deviation 11.7) in the conservative management arm and 50.4 (11.6) in the cholecystectomy arm. The SF-36 bodily pain area under the curve up to 18 months did not differ (mean difference 0.0, 95% confidence interval -1.7 to 1.7; P=1.00). Conservative management was less costly (mean difference -£1033, (-$1334; -€1205), 95% credible interval -£1413 to -£632) and QALYs did not differ (mean difference -0.019, 95% credible interval -0.06 to 0.02). CONCLUSIONS: In the short term (≤18 months), laparoscopic surgery is no more effective than conservative management for adults with uncomplicated symptomatic gallstone disease, and as such conservative management should be considered as an alternative to surgery. From an NHS perspective, conservative management may be cost effective for uncomplicated symptomatic gallstone disease. As costs, complications, and benefits will continue to be incurred in both groups beyond 18 months, future research should focus on longer term follow-up to establish effectiveness and lifetime cost effectiveness and to identify the cohort of patients who should be routinely offered surgery. TRIAL REGISTRATION: ISRCTN registry ISRCTN55215960.

Protocol for a randomised controlled trial comparing laparoscopic cholecystectomy with observation/conservative management for preventing recurrent symptoms and complications in adults with uncomplicated symptomatic gallstones (C-Gall trial).

BACKGROUND: Gallstone disease (cholelithiasis) is common. In most people it is asymptomatic and does not require treatment, but in about 20% it can become symptomatic, causing pain and other complications requiring medical attention and/or surgery. A proportion of symptomatic people with uncomplicated gallstone disease do not experience further episodes of pain and, therefore, could be treated conservatively. Moreover, surgery carries risks of perioperative and postoperative complications. METHODS AND ANALYSIS: C-Gall is a pragmatic, multicentre, randomised controlled trial and economic evaluation to assess whether cholecystectomy is cost-effective compared with observation/ conservative management (here after referred to as medical management) at 18 months post-randomisation (with internal pilot). PRIMARY OUTCOME MEASURE: Patient-reported quality of life (QoL) (36-Item Short Form Survey (SF-36) bodily pain domain) up to 18 months after randomisation.The primary economic outcome is incremental cost per quality-adjusted life year gained at 18 months. SECONDARY OUTCOME MEASURES: Secondary outcome measures include condition-specific QoL, SF-36 domains, complications, further treatment, persistent symptoms, healthcare resource use, and costs assessed at 18 and 24 months after randomisation. The bodily pain domain of the SF-36 will also be assessed at 24 months after randomisation.A sample size of 430 participants was calculated. Computer-generated 1:1 randomisation was used.The C-Gall Study is currently in follow-up in 20 UK research centres. The first patient was randomised on 1 August 2016, with follow-up to be completed by 30 November 2021. STATISTICAL ANALYSIS: Statistical analysis of the primary outcome will be intention-to-treat and a per-protocol analysis. The primary outcome, area under the curve (AUC) for the SF-36 bodily pain up to 18 months, will be generated using the Trapezium rule and analysed using linear regression with adjustment for the minimisation variables (recruitment site, sex and age). For the secondary outcome, SF-36 bodily pain, AUC up to 24 months will be analysed in a similar way. Other secondary outcomes will be analysed using generalised linear models with adjustment for minimisation and baseline variables, as appropriate. Statistical significance will be at the two-sided 5% level with corresponding CIs. ETHICS AND DISSEMINATION: The North of Scotland Research Ethics Committee approved this study (16/NS/0053). The dissemination plans include Health Technology Assessment monograph, international scientific meetings and publications in high-impact, open-access journals. TRIAL REGISTRATION NUMBER: ISRCTN55215960; pre-results.

Assessment of functional capacity before major non-cardiac surgery: an international, prospective cohort study.

BACKGROUND: Functional capacity is an important component of risk assessment for major surgery. Doctors' clinical subjective assessment of patients' functional capacity has uncertain accuracy. We did a study to compare preoperative subjective assessment with alternative markers of fitness (cardiopulmonary exercise testing [CPET], scores on the Duke Activity Status Index [DASI] questionnaire, and serum N-terminal pro-B-type natriuretic peptide [NT pro-BNP] concentrations) for predicting death or complications after major elective non-cardiac surgery. METHODS: We did a multicentre, international, prospective cohort study at 25 hospitals: five in Canada, seven in the UK, ten in Australia, and three in New Zealand. We recruited adults aged at least 40 years who were scheduled for major non-cardiac surgery and deemed to have one or more risk factors for cardiac complications (eg, a history of heart failure, stroke, or diabetes) or coronary artery disease. Functional capacity was subjectively assessed in units of metabolic equivalents of tasks by the responsible anaesthesiologists in the preoperative assessment clinic, graded as poor (<4), moderate (4-10), or good (>10). All participants also completed the DASI questionnaire, underwent CPET to measure peak oxygen consumption, and had blood tests for measurement of NT pro-BNP concentrations. After surgery, patients had daily electrocardiograms and blood tests to measure troponin and creatinine concentrations until the third postoperative day or hospital discharge. The primary outcome was death or myocardial infarction within 30 days after surgery, assessed in all participants who underwent both CPET and surgery. Prognostic accuracy was assessed using logistic regression, receiver-operating-characteristic curves, and net risk reclassification. FINDINGS: Between March 1, 2013, and March 25, 2016, we included 1401 patients in the study. 28 (2%) of 1401 patients died or had a myocardial infarction within 30 days of surgery. Subjective assessment had 19·2% sensitivity (95% CI 14·2-25) and 94·7% specificity (93·2-95·9) for identifying the inability to attain four metabolic equivalents during CPET. Only DASI scores were associated with predicting the primary outcome (adjusted odds ratio 0·96, 95% CI 0·83-0·99; p=0·03). INTERPRETATION: Subjectively assessed functional capacity should not be used for preoperative risk evaluation. Clinicians could instead consider a measure such as DASI for cardiac risk assessment. FUNDING: Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Ontario Ministry of Health and Long-Term Care, Ontario Ministry of Research, Innovation and Science, UK National Institute of Academic Anaesthesia, UK Clinical Research Collaboration, Australian and New Zealand College of Anaesthetists, and Monash University.

The clinical effectiveness and cost-effectiveness of point-of-care tests (CoaguChek system, INRatio2 PT/INR monitor and ProTime Microcoagulation system) for the self-monitoring of the coagulation status of people receiving long-term vitamin K antagonist therapy, compared with standard UK practice: systematic review and economic evaluation.

BACKGROUND: Self-monitoring (self-testing and self-management) could be a valid option for oral anticoagulation therapy monitoring in the NHS, but current evidence on its clinical effectiveness or cost-effectiveness is limited. OBJECTIVES: We investigated the clinical effectiveness and cost-effectiveness of point-of-care coagulometers for the self-monitoring of coagulation status in people receiving long-term vitamin K antagonist therapy, compared with standard clinic monitoring. DATA SOURCES: We searched major electronic databases (e.g. MEDLINE, MEDLINE In Process & Other Non-Indexed Citations, EMBASE, Bioscience Information Service, Science Citation Index and Cochrane Central Register of Controlled Trials) from 2007 to May 2013. Reports published before 2007 were identified from the existing Cochrane review (major databases searched from inception to 2007). The economic model parameters were derived from the clinical effectiveness review, other relevant reviews, routine sources of cost data and clinical experts' advice. REVIEW METHODS: We assessed randomised controlled trials (RCTs) evaluating self-monitoring in people with atrial fibrillation or heart valve disease requiring long-term anticoagulation therapy. CoaguChek(®) XS and S models (Roche Diagnostics, Basel, Switzerland), INRatio2(®) PT/INR monitor (Alere Inc., San Diego, CA USA), and ProTime Microcoagulation system(®) (International Technidyne Corporation, Nexus Dx, Edison, NJ, USA) coagulometers were compared with standard monitoring. Where possible, we combined data from included trials using standard inverse variance methods. Risk of bias assessment was performed using the Cochrane risk of bias tool. A de novo economic model was developed to assess the cost-effectiveness over a 10-year period. RESULTS: We identified 26 RCTs (published in 45 papers) with a total of 8763 participants. CoaguChek was used in 85% of the trials. Primary analyses were based on data from 21 out of 26 trials. Only four trials were at low risk of bias. Major clinical events: self-monitoring was significantly better than standard monitoring in preventing thromboembolic events [relative risk (RR) 0.58, 95% confidence interval (CI) 0.40 to 0.84; p = 0.004]. In people with artificial heart valves (AHVs), self-monitoring almost halved the risk of thromboembolic events (RR 0.56, 95% CI 0.38 to 0.82; p = 0.003) and all-cause mortality (RR 0.54, 95% CI 0.32 to 0.92; p = 0.02). There was greater reduction in thromboembolic events and all-cause mortality through self-management but not through self-testing. Intermediate outcomes: self-testing, but not self-management, showed a modest but significantly higher percentage of time in therapeutic range, compared with standard care (weighted mean difference 4.44, 95% CI 1.71 to 7.18; p = 0.02). Patient-reported outcomes: improvements in patients' quality of life related to self-monitoring were observed in six out of nine trials. High preference rates were reported for self-monitoring (77% to 98% in four trials). Net health and social care costs over 10 years were £7295 (self-monitoring with INRatio2); £7324 (standard care monitoring); £7333 (self-monitoring with CoaguChek XS) and £8609 (self-monitoring with ProTime). The estimated quality-adjusted life-year (QALY) gain associated with self-monitoring was 0.03. Self-monitoring with INRatio2 or CoaguChek XS was found to have ≈ 80% chance of being cost-effective, compared with standard monitoring at a willingness-to-pay threshold of £20,000 per QALY gained. CONCLUSIONS: Compared with standard monitoring, self-monitoring appears to be safe and effective, especially for people with AHVs. Self-monitoring, and in particular self-management, of anticoagulation status appeared cost-effective when pooled estimates of clinical effectiveness were applied. However, if self-monitoring does not result in significant reductions in thromboembolic events, it is unlikely to be cost-effective, based on a comparison of annual monitoring costs alone. Trials investigating the longer-term outcomes of self-management are needed, as well as direct comparisons of the various point-of-care coagulometers. STUDY REGISTRATION: This study is registered as PROSPERO CRD42013004944. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Is self-monitoring an effective option for people receiving long-term vitamin K antagonist therapy? A systematic review and economic evaluation.

OBJECTIVES: To investigate the clinical and cost-effectiveness of self-monitoring of coagulation status in people receiving long-term vitamin K antagonist therapy compared with standard clinic care. DESIGN: Systematic review of current evidence and economic modelling. DATA SOURCES: Major electronic databases were searched up to May 2013. The economic model parameters were derived from the clinical effectiveness review, routine sources of cost data and advice from clinical experts. STUDY ELIGIBILITY CRITERIA: Randomised controlled trials (RCTs) comparing self-monitoring versus standard clinical care in people with different clinical conditions. Self-monitoring included both self-management (patients conducted the tests and adjusted their treatment according to an algorithm) and self-testing (patients conducted the tests, but received treatment recommendations from a clinician). Various point-of-care coagulometers were considered. RESULTS: 26 RCTs (8763 participants) were included. Both self-management and self-testing were as safe as standard care in terms of major bleeding events (RR 1.08, 95% CI 0.81 to 1.45, p=0.690, and RR 0.99, 95% CI 0.80 to 1.23, p=0.92, respectively). Self-management was associated with fewer thromboembolic events (RR 0.51, 95% CI 0.37 to 0.69, p ≤ 0.001) and with a borderline significant reduction in all-cause mortality (RR 0.68, 95% CI 0.46 to 1.01, p=0.06) than standard care. Self-testing resulted in a modest increase in time in therapeutic range compared with standard care (weighted mean difference, WMD 4.4%, 95% CI 1.71 to 7.18, p=0.02). Total health and social care costs over 10 years were £7324 with standard care and £7326 with self-monitoring (estimated quality adjusted life year, QALY gain was 0.028). Self-monitoring was found to have ∼ 80% probability of being cost-effective compared with standard care applying a ceiling willingness-to-pay threshold of £20,000 per QALY gained. Within the base case model, applying the pooled relative effect of thromboembolic events, self-management alone was highly cost-effective while self-testing was not. CONCLUSIONS: Self-monitoring appears to be a safe and cost-effective option. TRIAL REGISTRATION NUMBER: PROSPERO CRD42013004944.

A practical assessment of the short-term in vitro stability of troponin I at the 99 th percentile.

BACKGROUND: Serial troponin measurement is important for the diagnosis of myocardial infarction. As troponin concentrations approach the cut-off for detectable myocardial necrosis, smaller changes in troponin as a result of decreased in vitro stability may be sufficient to generate changes of apparent clinical significance. This is particularly relevant regarding retrospective 'add-on' testing on samples several hours after venepuncture. We investigated the stability of troponin I (cTnI) at values close to the 99th percentile limit. METHODS: Serum samples with baseline cTnI concentrations in the range 0.04-0.15 µg/L were analysed routinely using the Siemens TnI-Ultra assay. Follow-up analysis was carried out at 6, 9, 12, 24 and 48 h post-venepuncture after storage at room temperature and in the cold room. RESULTS: There was a significant decrease in cTnI concentration after 6 h post-venepuncture compared with baseline levels (P < 0.001). The maximum percentage change was -17.1% observed after 48 h storage at room temperature. Of samples with baseline cTnI concentration 0.040 µg/L, 80% had a cTnI concentration below 0.040 µg/L on re-analysis after 6 h. CONCLUSIONS: Requests for retrospective addition of troponin measurement on samples several hours after venepuncture is commonplace in many laboratories. Analysis of samples drawn >6 h previously may produce values below the cut-off for myocardial necrosis (0.040 µg/L) that would have been detectable if measured earlier as a result of decreased in vitro stability. Significant percentage decreases in cTnI concentration following storage may also have implications in lowering the threshold for an apparently clinically significant change to occur.

Noninvasive assessment of left ventricular filling pressure after acute myocardial infarction: a prospective study of the relative prognostic utility of clinical assessment, echocardiography, and B-type natriuretic peptide.

BACKGROUND: Elevated left ventricular filling pressure after acute myocardial infarction (AMI) may be identified using clinical assessment, echocardiography, and B-type natriuretic peptide (BNP) levels. All of these predict outcome in this setting. There are, however, no data assessing their relative prognostic value. The current study addresses this. METHODS: Four hundred patients underwent detailed echocardiography and measurement of BNP levels after AMI (median 1 day). The study end points were (1) a composite of death, recurrent AMI, and/or admission to hospital with heart failure within 1 year and (2) all-cause mortality during medium-term follow-up (median 2.9 years). RESULTS: Both an elevated ratio of early transmitral flow to early mitral annulus velocity (E/e') and higher BNP levels were associated with an increased risk of an adverse event within the first year (odds ratio 6.14 for E/e' >15, P < .001; odds ratio 1.19 per 50-pg/mL increase in BNP, P < .001) and medium-term mortality (hazard ratio 4.67 for E/e' >15, P < .001; hazard ratio 1.10 per 50-pg/mL increase in BNP, P < .001). Among patients with BNP levels higher than the median or in the upper quartile, an E/e' ratio >15 identified a subgroup at greatest risk of mortality (P < .001 for both). CONCLUSIONS: The E/e' ratio and BNP levels play important and complementary roles in the risk stratification of patients after AMI.