Cochrane Handbook for Systematic Reviews of Interventions

Conditional outcomes only available for subsets of participants 173 6.10 Chapter information 174 6.11 References 174 7 Considering bias and conflicts of interest among the included studies 177 7.1 Introduction 177 7.2 Empirical evidence of bias 180 7.3 General procedures for risk-of-bias assessment 185 7.4 Presentation of assessment of risk of bias 188 7.5 Summary assessments of risk of bias 188 7.6 Incorporating assessment of risk of bias into analyses 190 7.7 Considering risk of bias due to missing results 192 7.8 Considering source of funding and conflict of interest of authors of included studies 193 7.9 Chapter information 199 7.10 References 199 8 Assessing risk of bias in a randomized trial 205 8.1 Introduction 205 8.2 Overview of RoB 2 206 8.3 Bias arising from the randomization process 212 8.4 Bias due to deviations from intended interventions 214 8.5 Bias due to missing outcome data 217 8.6 Bias in measurement of the outcome 220 8.7 Bias in selection of the reported result 221 8.8 Differences from the previous version of the tool 225 8.9 Chapter information 226 8.10 References 227 9 Summarizing study characteristics and preparing for synthesis 229 9.1 Introduction 229 9.2 A general framework for synthesis 230 9.3 Preliminary steps of a synthesis 231 9.4 Checking data before synthesis 238 9.5 Types of synthesis 238 9.6 Chapter information 240 9.7 References 240 10 Analysing data and undertaking meta-analyses 241 10.1 Do not start here! 242 10.2 Introduction to meta-analysis 242 10.3 A generic inverse-variance approach to meta-analysis 245 10.4 Meta-analysis of dichotomous outcomes 246 10.5 Meta-analysis of continuous outcomes 251 10.6 Combining dichotomous and continuous outcomes 254 10.7 Meta-analysis of ordinal outcomes and measurement scales 255 10.8 Meta-analysis of counts and rates 255 10.9 Meta-analysis of time-to-event outcomes 256 10.10 Heterogeneity 257 10.11 Investigating heterogeneity 265 10.12 Missing data 272 10.13 Bayesian approaches to meta-analysis 276 10.14 Sensitivity analyses 277 10.15 Chapter information 279 10.16 References 280 11 Undertaking network meta-analyses 285 11.1 What is network meta-analysis? 285 11.2 Important concepts 287 11.3 Planning a Cochrane Review to compare multiple interventions 293 11.4 Synthesis of results 297 11.5 Evaluating confidence in the results of a network meta-analysis 304 11.6 Presenting network meta-analyses 309 11.7 Concluding remarks 315 11.8 Chapter information 316 11.9 References 316 12 Synthesizing and presenting findings using other methods 321 12.1 Why a meta-analysis of effect estimates may not be possible 321 12.2 Statistical synthesis when meta-analysis of effect estimates is not possible 324 12.3 Visual display and presentation of the data 330 12.4 Worked example 333 12.5 Chapter information 345 12.6 References 346 13 Assessing risk of bias due to missing results in a synthesis 349 13.1 Introduction 350 13.2 Minimizing risk of bias due to missing results 351 13.3 A framework for assessing risk of bias due to missing results in a synthesis 354 13.4 Summary 369 13.5 Chapter information 370 13.6 References 370 14 Completing 'Summary of findings' tables and grading the certainty of the evidence 375 14.1 'Summary of findings' tables 375 14.2 Assessing the certainty or quality of a body of evidence 389 14.3 Describing the assessment of the certainty of a body of evidence using the GRADE framework 398 14.4 Chapter information 399 14.5 References 399 15 Interpreting results and drawing conclusions 403 15.1 Introduction 403 15.2 Issues of indirectness and applicability 405 15.3 Interpreting results of statistical analyses 408 15.4 Interpreting results from dichotomous outcomes (including numbers needed to treat) 411 15.5 Interpreting results from continuous outcomes (including standardized mean differences) 416 15.6 Drawing conclusions 422 15.7 Chapter information 427 15.8 References 428 Part Two Specific perspectives in reviews 433 16 Equity and specific populations 435 16.1 Introduction to equity in systematic reviews 435 16.2 Formulation of the review 437 16.3 Identification of evidence 441 16.4 Appraisal of evidence 443 16.5 Synthesis of evidence 443 16.6 Interpretation of evidence 444 16.7 Concluding remarks 445 16.8 Chapter information 445 16.9 References 445 17 Intervention complexity 451 17.1 Introduction 451 17.2 Formulation of the review 461 17.3 Identification of evidence 468 17.4 Appraisal of evidence 469 17.5 Synthesis of evidence 469 17.6 Interpretation of evidence 472 17.7 Chapter information 473 17.8 References 474 18 Patient-reported outcomes 479 18.1 Introduction to patient-reported outcomes 479 18.2 Formulation of the review 480 18.3 Appraisal of evidence 482 18.4 Synthesis and interpretation of evidence 485 18.5 Chapter information 488 18.6 References 489 19 Adverse effects 493 19.1 Introduction to issues in addressing adverse effects 493 19.2 Formulation of the review 496 19.3 Identification of evidence 500 19.4 Appraisal of evidence 502 19.5 Synthesis and interpretation of evidence 503 19.6 Chapter information 504 19.7 References 505 20 Economic evidence 507 20.1 Introduction 507 20.2 Formulation of the review 512 20.3 Identification of evidence 517 20.4 Appraisal of evidence 519 20.5 Synthesis and interpretation of evidence 519 20.6 Chapter information 521 20.7 References 522 21 Qualitative evidence 525 21.1 Introduction 525 21.2 Designs for synthesizing and integrating qualitative evidence with intervention reviews 526 21.3 Defining qualitative evidence and studies 527 21.4 Planning a qualitative evidence synthesis linked to an intervention review 528 21.5 Question development 529 21.6 Questions exploring intervention implementation 530 21.7 Searching for qualitative evidence 531 21.8 Assessing methodological strengths and limitations of qualitative studies 532 21.9 Selecting studies to synthesize 533 21.10 Selecting a qualitative evidence synthesis and data extraction method 534 21.11 Data extraction 534 21.12 Assessing the confidence in qualitative synthesized findings 537 21.13 Methods for integrating the qualitative evidence synthesis with an intervention review 537 21.14 Reporting the protocol and qualitative evidence synthesis 538 21.15 Chapter information 539 21.16 References 539 Part Three Further topics 547 22 Prospective approaches to accumulating evidence 549 22.1 Introduction 549 22.2 Evidence surveillance: active monitoring of the accumulating evidence 550 22.3 Prospectively planned meta-analysis 554 22.4 Statistical analysis of accumulating evidence 561 22.5 Chapter information 564 22.6 References 565 23 Including variants on randomized trials 569 23.1 Cluster-randomized trials 569 23.2 Crossover trials 576 23.3 Studies with more than two intervention groups 585 23.4 Chapter information 590 23.5 References 591 24 Including non-randomized studies on intervention effects 595 24.1 Introduction 595 24.2 Developing criteria for including non-randomized studies of interventions 601 24.3 Searching for non-randomized studies of interventions 606 24.4 Selecting studies and collecting data 608 24.5 Assessing risk of bias in non-randomized studies 610 24.6 Synthesis of results from non-randomized studies 611 24.7 Interpretation and discussion 614 24.8 Chapter information 617 24.9 References 617 25 Assessing risk of bias in a non-randomized study 621 25.1 Introduction 622 25.2 Biases in non-randomized studies 623 25.3 The ROBINS-I tool 626 25.4 Risk of bias in follow-up (cohort) studies 632 25.5 Risk of bias in uncontrolled before-after studies (including interrupted time series) 635 25.6 Risk of bias in controlled before-after studies 638 25.7 Chapter information 640 25.8 References 640 26 Individual participant data 643 26.1 Introduction 643 26.2 Collecting IPD 647 26.3 Managing and checking IPD 650 26.4 Analysis of IPD 652 26.5 Reporting IPD reviews 655 26.6 Appraising the quality of IPD reviews 655 26.7 Chapter information 655 26.8 References 655 Index 659