Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Cyclosporine-A Versus Prednisolone for Induction of Remission in Auto-immune Hepatitis: Interim Analysis Report of a Randomized Controlled Trial

BACKGROUND

Corticosteroids are used to induce remission in auto-immune hepatitis.They are not universally effective; therefore, alternative treatments are needed.In this study Cysclosporine-A has been compared with prednisolone as an alternativetreatment in a randomized controlled trial. This paper is an interimanalysis of an ongoing clinical trial.

METHODS

Sixteen years and older consenting patients were enrolled. Group-A receivedprednisolone and group-B cyclosporine-A according to a preset protocoland followed at regular intervals for 48 weeks. Final assessment was doneat week 48. Primary outcome was response rate as defined below. "Completeresponse" was defined as achieving AST and ALT in the normal range andabsence of any clinical signs of deterioration, and partial response was definedas a decrease in AST and ALT by less than half of their original values but notto within normal limit. Non-responding ones at week eight were switched tothe other arm.

RESULTS

Thirty-nine patients were enrolled (24 group-A, 9 male). Mean AST andALT at baseline were higher in group-B, but other variables were comparable.At week 12, 34.8% and 64.3% of group-A and B had achieved AST and ALTin the normal range (less than 40 IU/L) respectively (p=0.081). Correspondingfigures at week 48 were 50.0% and 47.6% (p=0.62 & 0.48 respectively).At week 12, 86.9% and 85.7% of patients had AST and ALT levels less thantwice upper normal limit in groups-A and B respectively (p=0.54 & 0.42).Corresponding figures at week 48 were 90.0% for both groups. There was onetreatment failure in group-B which did not respond to prednisolone either.Serious adverse events (death and liver transplantation) occurred in group-Aonly. Serum creatinine did not change during the study period in either group.

CONCLUSION

According to our data, Cyclosporine-A is as effective as prednisolone forinduction of remission in AIH. Adverse events and serious adverse events weremore common with prednisolone.