Lessons learned from the European thoracic surgery database: The composite performance score

A systematic review of risk prediction models for perioperative mortality after thoracic surgery

OBJECTIVES

Guidelines advocate that patients being considered for thoracic surgery should undergo a comprehensive preoperative risk assessment. Multiple risk prediction models to estimate the risk of mortality after thoracic surgery have been developed, but their quality and performance has not been reviewed in a systematic way. The objective was to systematically review these models and critically appraise their performance.

METHODS

The Cochrane Library and the MEDLINE database were searched for articles published between 1990 and 2019. Studies that developed or validated a model predicting perioperative mortality after thoracic surgery were included. Data were extracted based on the checklist for critical appraisal and data extraction for systematic reviews of prediction modelling studies.

RESULTS

A total of 31 studies describing 22 different risk prediction models were identified. There were 20 models developed specifically for thoracic surgery with two developed in other surgical specialties. A total of 57 different predictors were included across the identified models. Age, sex and pneumonectomy were the most frequently included predictors in 19, 13 and 11 models, respectively. Model performance based on either discrimination or calibration was inadequate for all externally validated models. The most recent data included in validation studies were from 2018. Risk of bias (assessed using Prediction model Risk Of Bias ASsessment Tool) was high for all except two models.

CONCLUSIONS

Despite multiple risk prediction models being developed to predict perioperative mortality after thoracic surgery, none could be described as appropriate for contemporary thoracic surgery. Contemporary validation of available models or new model development is required to ensure that appropriate estimates of operative risk are available for contemporary thoracic surgical practice.

Ninety-Day Mortality: Redefining the Perioperative Period After Lung Resection

Operative mortality is an important outcome for patients, surgeons, healthcare institutions, and policy makers. Although measures of perioperative mortality have conventionally been limited to in-hospital and 30-day mortality (or a composite endpoint combining both), there is a large body of evidence emerging to support the extension of the perioperative period after lung resection to a minimum of 90 days after surgery. Several large-volume studies from centers across the world have reported that 90-day mortality after lung resection is double 30-day mortality. Hence, true perioperative mortality after lung resection is likely to be significantly higher than what is currently reported. In the contemporary era, where new treatment modalities such as stereotactic ablative body radiotherapy are emerging as viable nonsurgical alternatives for the treatment of lung cancer, accurate estimation of perioperative risk and reliable reporting of perioperative mortality are of particular importance. It is likely that shifting the discussion from 30-day to 90-day mortality will lead to altered decision making, particularly for specific patient subgroups at an increased risk of 90-day mortality. We believe that 90-day mortality should be adopted as the standard measure of perioperative mortality after lung resection and that strategies to reduce the risk of mortality within 90 days of surgery should be investigated.

External validation of six existing multivariable clinical prediction models for short-term mortality in patients undergoing lung resection

 

OBJECTIVES

National guidelines advocate the use of clinical prediction models to estimate perioperative mortality for patients undergoing lung resection. Several models have been developed that may potentially be useful but contemporary external validation studies are lacking. The aim of this study was to validate existing models in a multicentre patient cohort.

METHODS

The Thoracoscore, Modified Thoracoscore, Eurolung, Modified Eurolung, European Society Objective Score and Brunelli models were validated using a database of 6600 patients who underwent lung resection between 2012 and 2018. Models were validated for in-hospital or 30-day mortality (depending on intended outcome of each model) and also for 90-day mortality. Model calibration (calibration intercept, calibration slope, observed to expected ratio and calibration plots) and discrimination (area under receiver operating characteristic curve) were assessed as measures of model performance.

RESULTS

Mean age was 66.8 years (±10.9 years) and 49.7% (n = 3281) of patients were male. In-hospital, 30-day, perioperative (in-hospital or 30-day) and 90-day mortality were 1.5% (n = 99), 1.4% (n = 93), 1.8% (n = 121) and 3.1% (n = 204), respectively. Model area under the receiver operating characteristic curves ranged from 0.67 to 0.73. Calibration was inadequate in five models and mortality was significantly overestimated in five models. No model was able to adequately predict 90-day mortality.

CONCLUSIONS

Five of the validated models were poorly calibrated and had inadequate discriminatory ability. The modified Eurolung model demonstrated adequate statistical performance but lacked clinical validity. Development of accurate models that can be used to estimate the contemporary risk of lung resection is required.

Parsimonious Eurolung risk models to predict cardiopulmonary morbidity and mortality following anatomic lung resections: an updated analysis from the European Society of Thoracic Surgeons database

OBJECTIVES

To develop a simplified version of the Eurolung risk model to predict cardiopulmonary morbidity and 30-day mortality after lung resection from the ESTS database.

METHODS

A total of 82 383 lung resections (63 681 lobectomies, 3617 bilobectomies, 7667 pneumonectomies and 7418 segmentectomies) recorded in the ESTS database (January 2007-December 2018) were analysed. Multiple imputations with chained equations were performed on the predictors included in the original Eurolung models. Stepwise selection was then applied for determining the best logistic model. To develop the parsimonious models, different models were tested eliminating variables one by one starting from the less significant. The models' prediction power was evaluated estimating area under curve (AUC) with the 10-fold cross-validation technique.

RESULTS

Cardiopulmonary morbidity model (Eurolung1): the best parsimonious Eurolung1 model contains 5 variables. The logit of the parsimonious Eurolung1 model was as follows: -2.852 + 0.021 × age + 0.472 × male -0.015 × ppoFEV1 + 0.662×thoracotomy + 0.324 × extended resection. Pooled AUC is 0.710 [95% confidence interval (CI) 0.677-0.743]. Mortality model (Eurolung2): the best parsimonious model contains 6 variables. The logit of the parsimonious Eurolung2 model was as follows: -6.350 + 0.047 × age + 0.889 × male -0.055 × BMI -0.010 × ppoFEV1 + 0.892 × thoracotomy + 0.983 × pneumonectomy. Pooled AUC is 0.737 (95% CI 0.702-0.770). An aggregate parsimonious Eurolung2 was also generated by repeating the logistic regression after categorization of the numeric variables. Patients were grouped into 7 risk classes showing incremental risk of mortality (P < 0.0001).

CONCLUSIONS

We were able to develop simplified and updated versions of the Eurolung risk models retaining the predictive ability of the full original models. They represent a more user-friendly tool designed to inform the multidisciplinary discussion and shared decision-making process of lung resection candidates.

Quality Control in Anatomical Lung Resection. Major Postoperative Complications vs Failure to Rescue

OBJECTIVES

Failure to rescue (FTR) is defined by the number of deaths among patients experiencing major complications after surgery. In this report we analyze FTR and apply a cumulative sum control chart (CUSUM) methodology for monitoring performance in a large series of operated lung carcinoma patients.

METHODS

Prospectively stored records of cases undergoing anatomical lung resection in one center were reviewed. Postoperative adverse events were coded and included as a binary variable (major, or minor complications). The occurrence of 30-day mortality was also recorded. Patients dying after suffering major complications were considered as FTR. Risk-adjusted CUSUM graphs using EuroLung1 and 2 variables were constructed for major complications and FTR. Points of plateauing or trend inversion were checked to detect intentional or non-adverted changes in the process of care.

RESULTS

2237 cases included. 9.1% cases suffered major complications. The number of cases considered as failures to rescuing was 46 (2.1% of the total series and 22.5% of cases having major complications). The predictive performance of EuroLung1 and 2 models was as follows: EuroLung1 (major morbidity) C-index 0.70 (95%CI: 0.66-0.73); EuroLung2 (applied to FTR) C-index 0.81 (95%CI: 0.750.87). CUSUM graphs depicted improvement in rescuing complicated patients after case 330 but no improvement in the rate of non-complicated cases until case 720.

CONCLUSIONS

FTR offers a complementary view to classical outcomes for quality assessment in Thoracic Surgery. Our study also shows how the analysis of FTR on time series can be applied to evaluate changes in team performance along time.

Blazing new trails: initial efforts to create a joint Society of Thoracic Surgeons-European Society of Thoracic Surgeons (STS-ESTS) dataset

Over the past 5 years, there has been an increased focus on international database collaboration between the Society of Thoracic Surgeons (STS) General Thoracic Surgery Database (GTSD) and European Society of Thoracic Surgeons (ESTS) Registry Task Forces. To this end, a joint STS-ESTS database Task Force meeting is held each year at the STS annual meeting, during which current and future projects are discussed. As this relationship has evolved, various issues have been encountered that must be overcome to maximize the potential of this collaborative effort. This article provides an overview of the STS GTSD and ESTS Registry, past projects, and the challenges faced by the Societal Task Forces as future projects are envisioned.

Focus on specific disease-part 2: the European Society of Thoracic Surgery chest wall database

Background

Data collection has gained a great importance in numerous areas in the last years and also in the medical field. Collecting data is the key to knowledge and consequently improving data quality is fundamental, as the results of the data analysis can have a large impact on the clinical practice.

Methods

Collected data can be employed to assess the performance of surgeons or institutions and to implement hospital´s performance and productivity. The chest wall database is one of the satellites composing the European Society of Thoracic Surgery (ESTS) database and includes data on risk factors, surgical techniques, processes of care and outcomes related to chest wall pathologies. The participation to the registry is free and voluntary for the ESTS members. The ESTS chest wall database includes data on risk factors, surgical techniques, processes of care and outcomes related to chest wall pathologies. The collected data are designed for quality control and performance audit. Acquired data are anonymous, independently accessed and encrypted on a Dendrite platform, which provides data security and regular backups. The registry is managed by an external company (KData Clinicak Srl), which works together with the database committee in revising and updating periodically the database.

Results

The ESTS chest wall database is structured in four main sections: preoperative, intraoperative, postoperative and follow up. For each procedure registered in the database are collected a number of different variables regarding the patients' characteristics, the surgical technique, the postoperative course until the discharge and also follow up data. Correction of pectus excavatum is the most common procedures registered in 2017 (392 patients, 67% of all data), followed by pectus bar removal (159 patients, 27% of all procedures).

Conclusions

The ESTS chest wall database is an ambitious European project, which aims to standardize all chest wall procedures in all their aspects.

Beyond borders-international database collaboration in thoracic surgery

Thoracic surgery databases continue to emerge as pillars for institutional quality improvement and research endeavors. This paper reviews the current state of the largest thoracic surgery databases: the Thoracic Surgeons General Thoracic Surgery Database (STS-GTSD) and the European Society of Thoracic Surgery Database (ESTSD). In addition, we utilize these as a platform to evaluate the role and key ingredients for successful international database collaborations. Ultimately, collaborative efforts among large databases unify research efforts, foster cohesion, serve as benchmarks for quality improvement locally, nationally and internationally, promote comparative innovation, and ultimately improve patient outcomes.

European risk models for morbidity (EuroLung1) and mortality (EuroLung2) to predict outcome following anatomic lung resections: an analysis from the European Society of Thoracic Surgeons database

Objectives

To develop models of 30-day mortality and cardiopulmonary morbidity from data on anatomic lung resections deposited in the European Society of Thoracic Surgeons (ESTS) database.

Methods

Retrospective analysis of 47 960 anatomic lung resections from the ESTS database (July 2007-August 2015) (36 376 lobectomies, 2296 bilobectomies, 5040 pneumonectomies and 4248 segmentectomies). Logistic regression analyses were used to test the association between baseline and surgical variables and morbidity or mortality. Bootstrap resampling was used for internal validation and to check predictors of stability. Variables that occurred in more than 50% of the bootstrap samples were deemed reliable. User-friendly aggregate scores were then created by assigning points to each variable in the model by proportionally weighting the regression coefficients. Patients were grouped in classes of incremental risk according to their scores.

Results

Cardiopulmonary morbidity and 30-day mortality rates were 18.4% (8805 patients) and 2.7% (1295 patients). The following variables were reliably associated with morbidity after logistic regression analysis (C-index 0.68): male sex ( P  < 0.0001); age ( P  < 0.0001); predicted postoperative forced expiratory volume in 1 s (ppoFEV1) ( P  < 0.0001); coronary artery disease (CAD) ( P  < 0.0001); cerebrovascular disease (CVD) ( P  < 0.0001); chronic kidney disease ( P  < 0.0001); thoracotomy approach ( P  < 0.0001); and extended resections ( P  < 0.0001). All variables occurred in more than 95% of the bootstrap samples. An aggregate score was created that stratified the patients into six classes of incremental morbidity risk ( P  < 0.0001). The following variables were reliably associated with mortality after logistic regression analysis (C-index 0.74): male sex ( P  < 0.0001); age ( P  < 0.0001); ppoFEV1 ( P  < 0.0001); CAD ( P  = 0.003); CVD ( P  < 0.0001); body mass index ( P  < 0.0001); thoracotomy approach ( P  < 0.0001); pneumonectomy ( P  < 0.0001); and extended resections ( P  = 0.002). All variables occurred in more than 80% of bootstrap samples. An aggregate score was created that stratified the patients into six classes of incremental mortality risk ( P  < 0.0001).

Conclusions

The updated ESTS morbidity and mortality models can be used to define risk-adjust outcome indicators for auditing quality of care and to counsel patients about their surgical risk.

International General Thoracic Surgery Database Collaboration

One of the recent goals of the Society of Thoracic Surgeons General Thoracic Surgery Database (STS GTSD) Task Force has been an increased focus on international database collaboration. To date, such collaboration has primarily been with the European Society of Thoracic Surgeons (ESTS) Registry Task Force. This article provides an overview of the STS GTSD and ESTS registry, recent collaborative projects, obstacles encountered, and future directions for the databases.

What the Surgeon Needs to Know About Databases

Data collection is one of the most important instruments of any quality improvement initiatives. We have selected, summarized, and discussed 5 recent contributions mostly based on large international databases, which we considered most relevant to our specialty. They focused on different aspects: the selection and rigorous definition of the variables contained in the data set, the evaluation of a treatment or a pathway of care by the analysis of the observed outcomes, the identification of risk factors able to affect the surgical course, the measurement of the quality provided by a care giver, and the assessment of the quality of the data collected and the planning of quality improvement activities.

Outcome after video-assisted thoracoscopic surgery and open pulmonary lobectomy in patients with low VO2 max: a case-matched analysis from the ESTS database†

OBJECTIVES

The aim was to verify the association of low VO2 max with postoperative morbidity and mortality after video-assisted thoracoscopic surgery (VATS) or open pulmonary lobectomy using the European Society of Thoracic Surgeons (ESTS) database.

METHODS

A retrospective analysis of data collected from the ESTS database was conducted. A total of 1684 lobectomy patients with available VO2 max values were included (2007-14). Patients operated through VATS (281 patients) or thoracotomy (1403 patients) were separately analysed. Propensity score analyses were performed to match patients with high (≥15 ml/kg/min) and low VO2 max (<15 ml/kg/min) for each approach. The following variables were used to construct the score: age, body mass index, predicted postoperative forced expiratory volume in 1 s (%), coronary artery disease, American Society of Anaesthesiology grade and Eastern Cooperative Oncology Group performance score. Cardiopulmonary morbidity and 30-day mortality were compared between the matched groups.

RESULTS

Mean VO2 max was 17.4 ml/kg/min. A total of 471 patients (28%) had low VO2 max. Overall postoperative cardiopulmonary morbidity and mortality rates were 30% (505 patients) and 4.1% (70 patients), respectively. Morbidity and mortality rates in low VO2 max patients were 33% (156 patients) and 6% (28 patients), respectively. After VATS, cardiopulmonary morbidity and mortality rates were 2-fold (13 of 72, 18% vs 143 of 399, 36%, P = 0.003) and 5-fold (1 of 72, 1.4% vs 27 of 399, 6.7%, P = 0.09) lower compared with thoracotomy. Matched comparison after thoracotomy (399 pairs): Mortality was significantly higher in patients with low VO2 max (27 patients, 6.7%) compared with those with high VO2 max (11 patients, 2.8%, P = 0.008). Complication rates were similar between the two groups (low VO2 max: 143 patients, 36% vs high VO2 max: 133 patients, 33%, respectively, P = 0.5). Matched comparison after vats (72 pairs): Morbidity and mortality rates of patients with low VO2 max were similar to those of patients with high VO2 max (morbidity: 13 patients, 18% vs 17 patients, 24%, P = 0.4; mortality: 1 patient, 1.4% vs 4 patients, 5.5%, P = 0.4).

CONCLUSIONS

Low VO2 max was not associated with an increased surgical risk after VAT lobectomy, which challenges the traditional operability criteria when this technique is used.

Major morbidity after video-assisted thoracic surgery lung resections: a comparison between the European Society of Thoracic Surgeons definition and the Thoracic Morbidity and Mortality system

BACKGROUND

The thoracic morbidity and mortality (TM&M) classification system univocally encodes the postoperative adverse events by their management complexity. This study aims to compare the distribution of the severity of complications according to the TM&M system versus the distribution according to the classification proposed by European Society of Thoracic Surgeons (ESTS) Database in a population of patients submitted to video assisted thoracoscopic surgery (VATS) lung resection.

METHODS

A total of 227 consecutive patients submitted to VATS lobectomy for lung cancer were analyzed. Any complication developed postoperatively was graded from I to V according to the TM&M system, reflecting the increasing severity of its management. We verified the distribution of the different grades of complications and analyzed their frequency among those defined as "major cardiopulmonary complications" by the ESTS Database.

RESULTS

Following the ESTS definitions, 20 were the major cardiopulmonary complications [atrial fibrillation (AF): 10, 50%; adult respiratory distress syndrome (ARDS): 1, 5%; pulmonary embolism: 2, 10%; mechanical ventilation >24 h: 1, 5%; pneumonia: 3, 15%; myocardial infarct: 1, 5%; atelectasis requiring bronchoscopy: 2, 10%] of which 9 (45%) were reclassified as minor complications (grade II) by the TM&M classification system. According to the TM&M system, 10/34 (29.4%) of all complications were considered minor (grade I or II) while 21/34 (71.4%) as major (IIIa: 8, 23.5%; IIIb: 4, 11.7%; IVa: 8, 23.5%; IVb: 1, 2.9%; V: 3, 8.8%). Other 14 surgical complications occurred and were classified as major complications according to the TM&M system.

CONCLUSIONS

The distribution of postoperative complications differs between the two classification systems. The TM&M grading system questions the traditional classification of major complications following VATS lung resection and may be used as an additional endpoint for outcome analyses.

Reasons to participate in European Society of Thoracic Surgeons database

The process of data collection inevitably involves costs at various levels. Nevertheless, this effort is essential to base our knowledge and the consequent decision making on solid foundations. The European Society of Thoracic Surgeons (ESTS) database collects a large amount of data on general thoracic surgery derived from about 60 units representative of 11 nations. Since its beginning in 2001, the ESTS database has contributed to increase the knowledge and the quality of care in our specialty. The present paper illustrates the ultimate finalities and the obtained results of this data collection, providing a broad overview of the motivations to participate to the ESTS database.

European institutional accreditation of general thoracic surgery

To improve standardization of general thoracic surgery (GTS) practice across Europe, the European Society of Thoracic Surgeons (ESTS) has implemented a program of Institutional Accreditation. We reviewed the methods and rules of engagement of this program. A composite performance score (CPS) including outcome and process indicators is used to measure institutional performance and assess eligibility for accreditation. Eligible units are invited to participate and accept a local audit performed by an external auditors team composed by data inspectors and thoracic surgeons. In addition to data quality, a series of structural, procedural and qualification characteristics are inspected. Once the visit is complete, the team will produce an audit report to be sent to the members of the database committee for deliberation on the institutional accreditation of that unit. The Database committee will send an executive report to the ESTS Executive Committee for their final decision on the accreditation.

European perspectives in thoracic surgery

Europe, the old Continent, has been the cradle of thoracic surgery from the beginning of the last century. The structure and the activities of the European Society of Thoracic Surgeons (ESTS) activities are directed to enlighten the path, provide the tools and set the standards for a quality inspired practice in thoracic surgery.

Major morbidity after lung resection: a comparison between the European Society of Thoracic Surgeons Database system and the Thoracic Morbidity and Mortality system

OBJECTIVE

The Thoracic Morbidity and Mortality (TM&M) classification system is a method for univocally coding the postoperative adverse events by their complexity of management. The aim of the present study was to compare the distribution of the severity of complications according to the TM&M system versus the distribution according to the classification proposed by European Society of Thoracic Surgeons (ESTS) Database in a population of patients submitted to lung resection in our unit.

METHODS

457 patients with any type of complications (326 lobectomy, 60 pneumonectomy, 71 wedge/segmentectomy) out of 1,518 patients submitted to pulmonary resections (January 2000-April 2011) were analyzed. Each complication was graded from I to V (TM&M system), reflecting an increasing severity of management. We verified the distribution of the different grades of complications and analyzed their frequency among those defined as "major cardio-pulmonary complications" by the ESTS Database.

RESULTS

According to the TM&M system, 0.6% of complications were regarded as grade I, 66.3% as grade II, 9.5% as grade IIIa, 4.4% as grade IIIb, 6.8% as grade IVa, 3.3% as grade IVb and 9.1% as grade V. According to the ESTS definitions, 290 complications were regarded as "major". Sixty two percent of them were reclassified as minor complications (grade I or II) by the TM&M classification system.

CONCLUSIONS

The application of the TM&M grading system questions the traditional classification of complications following lung resection. This grading system may be used as an additional endpoint for outcome analyses.

Inefficiency as the major driver of excess costs in lung resection

BACKGROUND

Risk-adjusted outcomes of surgical care are important for quality and cost assessments. Although cardiac surgery is commonly studied, risk-adjusted analysis of excess costs of lung resection has not been pursued.

METHODS

We used 2002 to 2005 National Inpatient Sample of the Healthcare Cost and Utilization Project data to evaluate adverse outcomes and costs in elective lung resections in hospitals with more than 20 cases during that period. Adverse outcomes were inpatient death or excessive risk-adjusted postoperative stay. Logistic models were defined to predict adverse outcomes. Linear models were designed to predict costs. Hospital-specific adverse outcome rates and costs were measured to define performance outliers. Cost-effective reference hospitals were used to define total excess costs.

RESULTS

Among 12,182 patients at 215 hospitals undergoing lung resection, there were 336 inpatient deaths (2.8%) and 880 live discharges with prolonged risk-adjusted postoperative stay (7.2%). Predictive models for mortality and risk-adjusted postoperative stay had C statistics of 0.773 and 0.643, respectively. There were 11 ineffective hospitals (5.1%) with excessive adverse outcomes (P < .005) and 34 inefficient hospitals (15.8%) meeting quality measures but with higher than predicted costs (P < .0005). Ineffective hospitals had costs $1020 per case lower than predicted. Inefficient hospitals had costs $9978 higher than predicted.

CONCLUSIONS

Inefficiency is the major factor in excess inpatient costs associated with lung resection in this model. Although refinements in databases, including total physician costs and postdischarge adverse event costs, will alter models, excess costs of lung resection appear to be driven by inefficiency, not adverse outcomes.

Standardized combined outcome index as an instrument for monitoring performance after pulmonary resection

BACKGROUND

Modern healthcare systems demand more transparent and accurate monitoring of clinical performance with the purpose to improve standards of care in a cost-effective way. Outcomes, such as mortality, are still the most widely used quality indicators in our specialty. However, previous studies have shown that mortality alone does not reflect performance accurately in our specialty. Ideally, multiple risk-adjusted outcomes should be used for a more comprehensive assessment. The objective of this analysis was to develop and use an index combining multiple risk-adjusted outcomes to track down the performance of our thoracic surgery unit over time.

METHODS

In all, 511 major lung resections (465 lobectomies, 46 pneumonectomies) performed from January 2005 through September 2010 were analyzed. Four risk-adjusted outcomes were considered: 30 days or in-hospital mortality, cardiopulmonary morbidity, unplanned/emergency intensive care unit admission, and prolonged length of stay (more than 14 days, prolonged hospital stay). Risk adjustment was performed using published regression models. Each indicator was converted into its opposite (ie, mortality rate to survival rate) so that higher scores reflected better performance. Moreover, to account for differences in measurement scales, the standardized outcomes were rescaled according to their mean total standard deviations. Finally, the individual rescaled indicators of each year were summed to generate a combined outcome index.

RESULTS

Mean cumulative observed mortality, morbidity, unplanned intensive care unit, and prolonged hospital stay rates were 1.8%, 23%, 6.6%, and 7.4%, respectively. The combined outcome index scores showed a progressive improvement of performance during the study period, progressing from -3.48 in 2005 to 2.87 in 2009. The combined outcome index was also used prospectively in a variable life-adjusted display chart to track down trends of practice variation in the last 6 months.

CONCLUSIONS

The present analysis is proposed as a methodologic template for developing a risk-adjusted index combining four different outcomes. It aims at overcoming inherent limitations of outcomes when used individually for performance assessment. This or similar combined indexes may be effective instruments of internal clinical audit and could be incorporated along with process indicators in composite performance scores to more comprehensively evaluate the postoperative domain of our practice.

[Evaluation of the interobserver variability in the systematic classification of operative morbidity in lung resection]

OBJECTIVE

To quantify the interobserver variability in establishing a systematic classification for the operative morbidity of lung resection.

METHODS

Morbidity was classified retrospectively in a series of 499 prospective registries of patients who underwent major lung resection (458 lobectomies and 51 pneumonectomies). The systematic classification proposed by Seely et al. in 2010 was used. Each one of the authors independently classified the complications and the weighted kappa statistic was calculated.

RESULTS AND COMMENTS

The kappa index was 0.79. Although the value is high, it introduces a systematic bias in the classification of patient morbidity that indicates the need to very carefully evaluate the data entered into the multi-institutional registers in order to be able to obtain valid conclusions.

[Preoperative estimation of the risk of lung resection]

The present article discusses the two most up-to-date clinical practice guidelines containing the recommendations of US and European scientific societies on preoperative assessment of the risk of lung resection. Despite some differences between the two documents, both guidelines agree on the importance of routine preoperative measurement of diffusion lung capacity for carbon monoxide (DLCO) in the predictive value of exercise tests, especially measurement of maximal oxygen uptake per minute (VO(2max)). Precisely because of its ability to predict the risk of operative death, VO(2max) should be measured in patients with a forced expiratory volume in 1 second (FEV1) or DLCO below 80% of the theoretical value. The authors recommend using one of the two above-mentioned guidelines in clinical practice and periodically auditing the results to compare them with in-hospital mortality for lung resection in Europe, currently available through the European Association of Thoracic Surgeons. There is currently no validated risk index that could be directly applied in clinical decision making in lung resection.