1.1 Search policy
Using subject words combined with free words, we searched the CNKI, Wanfang, VIP, PubMed, EMbase, The Cochrane Library, and web of science databases, and the references of the papers were further traced. The search time limit for database construction is until June 2023. Search term are stroke, strokes, cerebrovascular accident*, CVA, cerebrovascular apoplexy, brain vascular accident*, cerebrovascular stroke*, apoplexy, cerebral stroke, acute stroke, acute cerebrovascular accident, cerebral infarction, cerebral hemorrhage, brain ischemia, pneumonia, SAP, pulmonary infection, lower respiratory infection, Stroke-Associated Pneumonia, Lung Inflammation, Pulmonary Inflammation, prediction model, risk prediction, mode, risk score, risk assessment. Taking the PubMed database as an example, the retrieval formula is as follows:
(((pneumonia[MeSH Terms]) OR (SAP[Title/Abstract] OR pulmonary infection[Title/Abstract] OR lower respiratory infection[Title/Abstract] OR Stroke-Associated Pneumonia[Title/Abstract] OR Lung Inflammation[Title/Abstract] OR Pulmonary Inflammation[Title/Abstract])) AND ((stroke[MeSH Terms]) OR (strokes[Title/Abstract] OR cerebrovascular accident*[Title/Abstract] OR CVA[Title/Abstract] OR cerebrovascular apoplexy[Title/Abstract] OR brain vascular accident*[Title/Abstract] OR cerebrovascular stroke*[Title/Abstract] OR apoplexy[Title/Abstract] OR cerebral stroke[Title/Abstract] OR acute stroke[Title/Abstract] OR acute cerebrovascular accident[Title/Abstract] OR cerebral infarction[Title/Abstract] OR cerebral hemorrhage[Title/Abstract] OR brain ischemia[Title/Abstract]))) AND (prediction model[Title/Abstract] OR risk prediction[Title/Abstract] OR mode[Title/Abstract] OR risk score[Title/Abstract] OR risk assessment[Title/Abstract])
1.2 Inclusion and exclusion criteria
Inclusion criteria:(1)The age of the research subject is ≥ 18 years old;(2)The research content is the construction of a risk prediction model for stroke associated pneumonia;(3)study type included cohort, cross-sectional, and case-control study;(4)outcome measures were SAP.
exclusion criteria:(1)Only for risk factor analysis, no model constructedl;(2)article language is not Chinese or English;(3)Informal publications such as conference abstracts and dissertations;(4)Research materials such as second-class literature, news reports, and case reports;(5)could not obtain full text;(6)only 1 predictor variable for model.
1.3 Literature screening and data extraction
Two researchers independently screened the literature according to the inclusion and exclusion criteria.Endnote X9 software was used to remove duplicates.Browsing the title and abstract, preliminary screening of literature according to inclusion and exclusion criteria, further review of literature that may meet the inclusion criteria, discussion or consultation with a third person in case of disagreement.The extracted data includes:first author, year of publication,country, study of type, study object, sample size,number of models, prevelance of SAP.
1.4 Assessment of the risk of bias and applicability of the included literature
Two researchers independently used the prediction model risk of bias assessment tool (PROBAST) to evaluate the bias risk and applicability of the models included in the literature12.
1.4.1 Risk of bias assessment
PROBAST divides the potential biases involved in predictive model research into four areas, namely research subjects, predictive factors, outcomes, and analysis, with a total of 20 questions. The evaluator makes judgments on each question, and the answers to each question include "yes/may be yes", "no/may not be", and "lack of information". The bias risk of the prediction model as a whole and each field is classified as low, high, or unclear.Only when all questions in the field are answered with "yes" or "may be" is considered "low risk", and as long as one question is answered with "no" or "may not be", it is considered "high risk".When a problem is judged as "ack of information" and all other problems are considered "low risk", the field is classified as"unclear".
1.4.2 Applicability evaluation
The applicability evaluation of predictive models includes three areas: research subjects, predictive factors, and outcomes.The overall applicability of the predictive model is rated as "low" ,"high" , '"unclear" . Only when all areas are considered"low risk",it is considered "low risk" as a whole. If one or more areas are considered"high risk", it is considered"high risk"as a whole.If a certain area is judged as"unclear"and all other areas are considered"low risk", then the overall classification is"unclear".
1.5 Statistical analysis
Use descriptive analysis to summarize and analyze the basic characteristics of the model and the bias risk and applicability evaluation results included in the study.