在没有明显临床指征的患者和常见合并症患者亚组中，在择期手术前常规检测全血细胞计数、电解质和尿素以及肺功能测试的价值：对临床和成本效益文献的系统评价。

Leeds Institute of Health Sciences, University of Leeds, Leeds, UK.

Health Technol Assess. 2012 Dec;16(50):i-xvi, 1-159. doi: 10.3310/hta16500.

BACKGROUND

The evidence base which supported the National Institute for Health and Clinical Excellence (NICE) published Clinical Guideline 3 was limited and 50% was graded as amber. However, the use of tests as part of pre-operative work-up remains a low-cost but high-volume activity within the NHS, with substantial resource implications. The objective of this study was to identify, evaluate and synthesise the published evidence on the clinical effectiveness and cost-effectiveness of the routine use of three tests, full blood counts (FBCs), urea and electrolytes tests (U&Es) and pulmonary function tests, in the pre-operative work-up of otherwise healthy patients undergoing minor or intermediate surgery in the NHS.

OBJECTIVE

The aims of this study were to estimate the clinical effectiveness and cost-effectiveness of routine pre-operative testing of FBC, electrolytes and renal function and pulmonary function in adult patients classified as American Society of Anaesthesiologists (ASA) grades 1 and 2 undergoing elective minor (grade 1) or intermediate (grade 2) surgical procedures; to compare NICE recommendations with current practice; to evaluate the cost-effectiveness of mandating or withdrawing each of these tests in this patient group; and to identify the expected value of information and whether or not it has value to the NHS in commissioning further primary research into the use of these tests in this group of patients.

DATA SOURCES

The following electronic bibliographic databases were searched: (1) BIOSIS; (2) Cumulative Index to Nursing and Allied Health Literature; (3) Cochrane Database of Systematic Reviews; (4) Cochrane Central Register of Controlled Trials; (5) EMBASE; (6) MEDLINE; (7) MEDLINE In-Process & Other Non-Indexed Citations; (8) NHS Database of Abstracts of Reviews of Effects; (9) NBS Health Technology Assessment Database; and (10) Science Citation Index. To identify grey and unpublished literature, the Cochrane Register of Controlled Trials, National Research Register Archive, National Institute for Health Research Clinical Research Network Portfolio database and the Copernic Meta-search Engine were searched. A large routine data set which recorded the results of tests was obtained from Leeds Teaching Hospitals Trust.

REVIEW METHODS

A systematic review of the literature was carried out. The searches were undertaken in March to April 2008 and June 2009. Searches were designed to retrieve studies that evaluated the clinical effectiveness and cost-effectiveness of routine pre-operative testing of FBC, electrolytes and renal function and pulmonary function in the above group of patients. A postal survey of current practice in testing patients in this group pre-operatively was undertaken in 2008. An exemplar cost-effectiveness model was constructed to demonstrate what form this would have taken had there been sufficient data. A large routine data set that recorded the results of tests was obtained from Leeds Teaching Hospitals Trust. This was linked to individual patient data with surgical outcomes, and regression models were estimated.

RESULTS

A comprehensive and systematic search of both the clinical effectiveness and cost-effectiveness literature identified a large number of potentially relevant studies. However, when these studies were subjected to detailed review and quality assessment, it became clear that the literature provides no evidence on the clinical effectiveness and cost-effectiveness of these specific tests in the specific patient groups. The postal survey had a 17% response rate. Results reported that in ASA grade 1, patients aged < 40 years with no comorbidities undergoing minor surgery did not have routine tests for FBC, electrolytes and renal function and pulmonary function. The results from the regression model showed that the frequency of test use was not consistent with the hypothesis of their routine use. FBC tests were performed in only 58% of patients in the data set and U&E testing was carried out in only 57%.

LIMITATIONS

Systematic searches of the clinical effectiveness and cost-effectiveness literature found that there is no evidence on the clinical effectiveness or cost-effectiveness of these tests in this specific clinical context for the NHS. A survey of NHS hospitals found that respondent trusts were implementing current NICE guidance in relation to pre-operative testing generally, and a de novo analysis of routine data on test utilisation and post-operative outcome found that the tests were not be used in routine practice; rather, use was related to an expectation of a more complex clinical case. The paucity of published evidence is a limitation of this study. The studies included relied on non-UK health-care systems data, which may not be transferable. The inclusion of non-randomised studies is associated with an increased risk of bias and confounding. Scoping work to establish the likely mechanism of action by which tests would impact upon outcomes and resource utilisation established that the cause of an abnormal test result is likely to be a pivotal determinant of the cost-effectiveness of a pre-operative test and therefore evaluations would need to consider tests in the context of the underlying risk of specific clinical problems (i.e. risk guided rather than routine use).

CONCLUSIONS

The time of universal utilisation of pre-operative tests for all surgical patients is likely to have passed. The evidence we have identified, though weak, indicates that tests are increasingly utilised in patients in whom there is a reason to consider an underlying raised risk of a clinical abnormality that should be taken into account in their clinical management. It is likely that this strategy has led to substantial resource savings for the NHS, although there is not a published evidence base to establish that this is the case. The total expenditure on pre-operative tests across the NHS remains significant. Evidence on current practice indicates that clinical practice has changed to such a degree that the original research question is no longer relevant to UK practice. Future research on the value of these tests in pre-operative work-up should be couched in terms of the clinical effectiveness and cost-effectiveness in the identification of specific clinical abnormalities in patients with a known underlying risk. We suggest that undertaking a multicentre study making use of linked, routinely collected data sets would identify the extent and nature of pre-operative testing in this group of patients.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

背景

支持英国国家卫生与临床优化研究所（NICE）发布的临床指南 3 的证据基础有限，其中 50%被评为琥珀色。然而，这些测试作为术前检查的一部分，仍然是英国国家医疗服务体系（NHS）中一项低成本但高容量的活动，具有重大的资源影响。本研究的目的是确定、评估和综合发表的关于在 NHS 中对接受小手术或中等手术的健康状况良好的成年患者进行常规使用全血细胞计数（FBC）、尿素和电解质测试（U&E）以及肺功能测试的临床有效性和成本效益的证据。

目的

本研究的目的是估计对接受美国麻醉医师协会（ASA）分级 1 和 2 的择期小手术（1 级）或中等手术（2 级）的成年患者进行常规术前 FBC、电解质和肾功能及肺功能检查的临床有效性和成本效益；比较 NICE 建议与当前实践；评估在这个患者群体中强制或撤回这些测试的成本效益；并确定信息的预期价值，以及它是否对 NHS 有价值，以委托对这群患者使用这些测试进行进一步的初级研究。

数据来源

检索了以下电子书目数据库：（1）BIOSIS；（2）护理与联合健康文献累积索引；（3）Cochrane 系统评价数据库；（4）Cochrane 对照试验中心注册库；（5）EMBASE；（6）MEDLINE；（7）MEDLINE 正在处理的文献及其他非索引引文；（8）NHS 数据库中的评价摘要；（9）NBS 卫生技术评估数据库；（10）科学引文索引。为了确定灰色和未发表的文献，还检索了 Cochrane 对照试验注册库、国家研究登记档案、国家卫生研究院临床研究网络投资组合数据库和 Copernic Meta-search 引擎。从利兹教学医院信托基金获得了一个大型常规数据集，该数据集记录了测试结果。

审查方法

对文献进行了系统评价。检索于 2008 年 3 月至 4 月和 2009 年 6 月进行。检索旨在检索评估上述患者常规进行术前 FBC、电解质和肾功能及肺功能测试的临床有效性和成本效益的研究。2008 年对该组患者术前进行测试的当前实践进行了邮政调查。构建了一个范例成本效益模型，以展示如果有足够的数据，它将采用何种形式。从利兹教学医院信托基金获得了一个大型常规数据集，该数据集记录了测试结果。该数据集与个体患者数据和手术结果相关联，并估计了回归模型。

结果

对临床有效性和成本效益文献进行了全面和系统的搜索，确定了大量潜在相关的研究。然而，当对这些研究进行详细审查和质量评估时，很明显，文献中没有关于这些特定测试在特定患者群体中的临床有效性和成本效益的证据。邮政调查的回复率为 17%。结果表明，在 ASA 分级 1 中，年龄<40 岁且无合并症的患者进行小手术时，不进行 FBC、电解质和肾功能及肺功能的常规检查。回归模型的结果表明，测试的使用频率与常规使用的假设不一致。在数据集的患者中，仅进行了 58%的 FBC 测试，U&E 测试仅进行了 57%。

局限性

对临床有效性和成本效益文献进行的系统搜索发现，对于 NHS 来说，没有关于这些测试在这一特定临床背景下的临床有效性或成本效益的证据。对 NHS 医院的调查发现，回应的信托机构普遍遵循当前 NICE 的术前测试指导，对常规测试使用和术后结果的分析发现，这些测试并未在常规实践中使用；相反，使用是基于对更复杂临床病例的预期。发表的证据不足是本研究的一个局限性。纳入的研究依赖于非英国的医疗保健系统数据，这些数据可能无法转移。非随机研究的纳入与偏倚和混杂的风险增加有关。对确定测试如何影响结果和资源利用的潜在机制进行的范围界定工作表明，测试结果异常的原因很可能是术前测试成本效益的关键决定因素，因此评估需要根据特定临床问题的潜在风险来考虑测试（即风险指导而不是常规使用）。

结论

对所有手术患者进行术前检查的普遍使用时代可能已经过去。我们所确定的证据虽然薄弱，但表明这些测试在有理由考虑潜在风险升高的情况下，越来越多地用于患有特定临床异常的患者，这些异常应在其临床管理中加以考虑。这可能导致 NHS 节省了大量资源，尽管没有发表的证据来确定这种情况。在 NHS 中，术前测试的总支出仍然很高。当前实践的证据表明，临床实践已经发生了如此大的变化，以至于最初的研究问题与英国的实践不再相关。未来关于这些测试在术前工作中的价值的研究应该从识别具有已知潜在风险的患者中特定临床异常的临床有效性和成本效益方面来进行。我们建议进行一项多中心研究，利用链接的常规收集数据集，以确定该组患者术前测试的程度和性质。