Evidence Based Medicine on FHIR Implementation Guide, published by HL7 International / Clinical Decision Support. This guide is not an authorized publication; it is the continuous build for version 2.0.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/ebm/ and changes regularly. See the Directory of published versions
<Evidence xmlns="http://hl7.org/fhir">
<id value="49328"/>
<meta>
<versionId value="25"/>
<lastUpdated value="2023-12-08T16:33:14.612Z"/>
<profile
value="http://hl7.org/fhir/uv/ebm/StructureDefinition/comparative-evidence"/>
<profile
value="http://hl7.org/fhir/uv/ebm/StructureDefinition/evidence-synthesis-evidence"/>
</meta>
<text>
<status value="generated"/>
<div xmlns="http://www.w3.org/1999/xhtml"><p class="res-header-id"><b>Generated Narrative: Evidence 49328</b></p><a name="49328"> </a><a name="hc49328"> </a><a name="49328-en-US"> </a><div style="display: inline-block; background-color: #d9e0e7; padding: 6px; margin: 4px; border: 1px solid #8da1b4; border-radius: 5px; line-height: 60%"><p style="margin-bottom: 0px">version: 25; Last updated: 2023-12-08 16:33:14+0000</p><p style="margin-bottom: 0px">Profiles: <a href="StructureDefinition-comparative-evidence.html">ComparativeEvidence</a>, <a href="StructureDefinition-evidence-synthesis-evidence.html">EvidenceSynthesisEvidence</a></p></div><p><b>url</b>: <a href="https://fevir.net/resources/Evidence/49328">https://fevir.net/resources/Evidence/49328</a></p><p><b>identifier</b>: FEvIR Object Identifier/49328</p><p><b>name</b>: AllCauseMortality2022metaAnalysis</p><p><b>title</b>: ComparativeEvidence: All-cause mortality effect of bariatric surgery in 2022 meta-analysis</p><p><b>status</b>: Active</p><p><b>date</b>: 2022-09-19 21:27:50+0000</p><p><b>publisher</b>: Computable Publishing LLC</p><p><b>contact</b>: <a href="mailto:support@computablepublishing.com">support@computablepublishing.com</a></p><p><b>author</b>: Brian S. Alper: </p><h3>UseContexts</h3><table class="grid"><tr><td style="display: none">-</td><td><b>Code</b></td><td><b>Value[x]</b></td></tr><tr><td style="display: none">*</td><td><a href="CodeSystem-179423.html#179423-evidence-communication">Evidence Based Medicine on FHIR Implementation Guide Code System evidence-communication</a>: Evidence Communication</td><td><span title="Codes:{https://fevir.net/resources/CodeSystem/179423 ComparativeEvidence}">ComparativeEvidence</span></td></tr><tr><td style="display: none">*</td><td><a href="CodeSystem-179423.html#179423-evidence-communication">Evidence Based Medicine on FHIR Implementation Guide Code System evidence-communication</a>: Evidence Communication</td><td><span title="Codes:{https://fevir.net/resources/CodeSystem/179423 EvidenceSynthesisEvidence}">EvidenceSynthesisEvidence</span></td></tr><tr><td style="display: none">*</td><td><a href="CodeSystem-179423.html#179423-evidence-communication">Evidence Based Medicine on FHIR Implementation Guide Code System evidence-communication</a>: Evidence Communication</td><td><span title="Codes:{https://fevir.net/resources/CodeSystem/179423 OutcomeMeasureEvidence}">OutcomeMeasureEvidence</span></td></tr></table><p><b>copyright</b>: </p><div><p>https://creativecommons.org/licenses/by-nc-sa/4.0/</p>
</div><blockquote><p><b>relatedArtifact</b></p><p><b>type</b>: Derived From</p><p><b>label</b>: data source</p><p><b>citation</b>: </p><div><p>Bariatric surgery and cardiovascular disease: a systematic review and meta-analysis [Journal Article]. Contributors: van Veldhuisen SL, Gorter TM, van Woerden G, de Boer RA, Rienstra M, Hazebroek EJ, van Veldhuisen DJ. In: European heart journal, PMID 35243488. Published March 04, 2022. Available at: https://pubmed.ncbi.nlm.nih.gov/35243488/.</p>
</div><h3>Documents</h3><table class="grid"><tr><td style="display: none">-</td><td><b>Url</b></td></tr><tr><td style="display: none">*</td><td><a href="https://academic.oup.com/eurheartj/article/43/20/1955/6542137">https://academic.oup.com/eurheartj/article/43/20/1955/6542137</a></td></tr></table></blockquote><blockquote><p><b>relatedArtifact</b></p><p><b>type</b>: Supported With</p><p><b>classifier</b>: <span title="Codes:">Citation Resource for the original article</span></p><p><b>display</b>: Citation Resource for 2022 Systematic Review of bariatric surgery mortality effect - PMID 35243488</p><p><b>resourceReference</b>: <a href="Citation-33400.html">StudyCitation: 2022 Systematic Review of bariatric surgery mortality effect 35243488</a></p></blockquote><blockquote><p><b>relatedArtifact</b></p><p><b>type</b>: Cite As</p><p><b>citation</b>: </p><div><p>ComparativeEvidence: All-cause mortality effect of bariatric surgery in 2022 meta-analysis [Evidence]. Contributors: Brian S. Alper [Authors/Creators]. In: Fast Evidence Interoperability Resources (FEvIR) Platform, FOI 49328. Revised 2022-09-19. Available at: https://fevir.net/resources/Evidence/49328. Computable resource at: https://fevir.net/resources/Evidence/49328.</p>
</div></blockquote><p><b>description</b>: </p><div><p>effect estimate for bariatric surgery on all-cause mortality pooled hazard ratio (HR) 0.55 (95% confidence interval 0.49 to 0.62; P < 0.001 vs. controls) in meta-analysis of 21 cohort studies with 133,524 patients after bariatric surgery and 263,478 obese controls</p>
</div><p><b>assertion</b>: </p><div><p>The present systematic review and meta-analysis suggests that bariatric surgery is associated with reduced all-cause and CV mortality.</p>
</div><blockquote><p><b>variableDefinition</b></p><p><b>description</b>: </p><div><p>obese, adult (age ≥18 years old) patients <em>NOTE: note.text is used artificially to support the EBMonFHIR Implementation Guide and the following content would more properly be found in a note.text element:</em> Studies were considered eligible if they were designed to study outcomes in obese patients who underwent a weight-loss surgical intervention in comparison with an age, sex, and BMI matched control group who did not undergo a weight-loss surgical intervention. We searched for randomized controlled trials, prospective or retrospective longitudinal cohort studies, and case–control studies. For the control group, all non-surgical treatment options for obesity (e.g. intensive lifestyle intervention, standard of care, or no specific therapy) were accepted. Studies were excluded if (i) patients were not matched for age, sex, and BMI; (ii) the presence of one or more outcome parameters of interest (e.g. HF, AF, coronary artery disease) was required for inclusion; or (iii) if study groups were not representative in relation to the general population of patients with obesity (e.g. patients could only be included in the presence of a specific comorbidity, for instance, end-stage renal disease). The third criterium did not apply to Type 2 diabetes, thus studies that only included patients with Type 2 diabetes could be eligible for inclusion.</p>
</div><p><b>variableRole</b>: Population</p><p><b>intended</b>: <a href="Group-171819.html">StudyEligibilityCriteria: Obese patients ≥ 18 years old</a></p></blockquote><blockquote><p><b>variableDefinition</b></p><p><b>description</b>: </p><div><p>comparison groups of bariatric surgery vs. no bariatric surgery <em>NOTE: note.text is used artificially to support the EBMonFHIR Implementation Guide and the following content would more properly be found in a note.text element:</em> As the control group (observed reference exposure) was defined differently in each study, the intended reference exposure is described as the absence of the intended exposure (Bariatric Surgery).</p>
</div><p><b>variableRole</b>: Exposure</p><p><b>comparatorCategory</b>: no bariatric surgery</p><p><b>intended</b>: <a href="EvidenceVariable-172427.html">GroupAssignment: Bariatric Surgery vs. no bariatric surgery</a></p></blockquote><blockquote><p><b>variableDefinition</b></p><p><b>description</b>: </p><div><p>All-cause mortality <em>NOTE: note.text is used artificially to support the EBMonFHIR Implementation Guide and the following content would more properly be found in a note.text element:</em> The observed element can reference an EvidenceVariable Resource that defines the outcome measured through structured characteristics. For example, “Mean difference in HbA1c at 12 months” or “Mean difference in HbA1c at end of study”. The structured characteristics can be references to the Evidence instances for each of the included studies, in which case this is a direct link to the dataset used for analysis. The intended element can reference an EvidenceVariable Resource that expresses the outcome intended for evidence application through structured characteristics. The structured characteristics could be used to express the SR eligibility criteria for study outcomes (as a subset of eligibility criteria for studies).</p>
</div><p><b>variableRole</b>: Outcome</p><p><b>observed</b>: We searched for randomized controlled trials, prospective or retrospective longitudinal cohort studies, and case–control studies. For the control group, all non-surgical treatment options for obesity (e.g. intensive lifestyle intervention, standard of care, or no specific therapy) were accepted. Studies were excluded if (i) patients were not matched for age, sex, and BMI; (ii) the presence of one or more outcome parameters of interest (e.g. HF, AF, coronary artery disease) was required for inclusion; or (iii) if study groups were not representative in relation to the general population of patients with obesity (e.g. patients could only be included in the presence of a specific comorbidity, for instance, end-stage renal disease). The third criterium did not apply to Type 2 diabetes, thus studies that only included patients with Type 2 diabetes could be eligible for inclusion.</p><p><b>intended</b>: <a href="EvidenceVariable-49217.html">OutcomeVariable: All-cause mortality</a></p></blockquote><p><b>synthesisType</b>: <span title="Codes:{http://terminology.hl7.org/CodeSystem/synthesis-type std-MA}">summary data meta-analysis</span></p><p><b>studyDesign</b>: <span title="Codes:{http://hl7.org/fhir/study-design SEVCO:01002}">Observational research</span>, <span title="Codes:{http://hl7.org/fhir/study-design SEVCO:01011}">Parallel cohort design</span>, <span title="Codes:{http://hl7.org/fhir/study-design SEVCO:01014}">Matching for comparison</span></p><blockquote><p><b>statistic</b></p><p><b>description</b>: </p><div><p>pooled hazard ratio (HR) 0.55 (95% confidence interval 0.49 to 0.62; P < 0.001 vs. controls) in meta-analysis of 21 cohort studies with 133,524 patients after bariatric surgery and 263,478 obese controls</p>
</div><p><b>note</b>: heterogeneity: Tau2 = 0.06; Chi2 = 105.14; df = 23 (P < 0.00001); I2 = 78%, test for overall effect z = 9.41 (p < 0.00001)</p><p><b>statisticType</b>: <span title="Codes:{http://terminology.hl7.org/CodeSystem/statistic-type C93150}">Hazard Ratio</span></p><p><b>quantity</b>: 0.55</p><h3>SampleSizes</h3><table class="grid"><tr><td style="display: none">-</td><td><b>Description</b></td><td><b>NumberOfStudies</b></td><td><b>NumberOfParticipants</b></td></tr><tr><td style="display: none">*</td><td><div><p>21 cohort studies with 133,524 patients after bariatric surgery and 263,478 obese controls</p>
</div></td><td>21</td><td>397002</td></tr></table><blockquote><p><b>attributeEstimate</b></p><p><b>description</b>: </p><div><p>95% confidence interval 0.49 to 0.62</p>
</div><p><b>type</b>: <span title="Codes:{http://terminology.hl7.org/CodeSystem/attribute-estimate-type C53324}">Confidence interval</span></p><p><b>level</b>: 0.95</p><p><b>range</b>: 0.49-0.62</p></blockquote><blockquote><p><b>attributeEstimate</b></p><p><b>description</b>: </p><div><p>z = 9.41</p>
</div><p><b>type</b>: <span title="Codes:{https://fevir.net/resources/CodeSystem/179423 defined-in-text}">Z-score</span></p><p><b>quantity</b>: 9.41</p></blockquote><blockquote><p><b>attributeEstimate</b></p><p><b>description</b>: </p><div><p>p < 0.00001</p>
</div><p><b>type</b>: <span title="Codes:{http://terminology.hl7.org/CodeSystem/attribute-estimate-type C44185}">P-value</span></p><p><b>quantity</b>: <1e-05</p></blockquote><blockquote><p><b>attributeEstimate</b></p><p><b>description</b>: </p><div><p>Tau squared = 0.06</p>
</div><p><b>type</b>: <span title="Codes:{http://terminology.hl7.org/CodeSystem/attribute-estimate-type 0000421}">Tau squared</span></p><p><b>quantity</b>: 0.06</p></blockquote><blockquote><p><b>attributeEstimate</b></p><p><b>description</b>: </p><div><p>Chi square for homogeneity 105.14, df 23 (p < 0.00001)</p>
</div><p><b>type</b>: <span title="Codes:{https://fevir.net/resources/CodeSystem/179423 defined-in-text}">Chi square for homogeneity</span></p><p><b>quantity</b>: 105.14</p><h3>AttributeEstimates</h3><table class="grid"><tr><td style="display: none">-</td><td><b>Description</b></td><td><b>Type</b></td><td><b>Quantity</b></td></tr><tr><td style="display: none">*</td><td><div><p>degrees of freedom (df) = 23</p>
</div></td><td><span title="Codes:{https://fevir.net/resources/CodeSystem/179423 defined-in-text}">Degrees of Freedom</span></td><td>23</td></tr><tr><td style="display: none">*</td><td><div><p>p < 0.00001</p>
</div></td><td><span title="Codes:{http://terminology.hl7.org/CodeSystem/attribute-estimate-type C44185}">P-value</span></td><td><1e-05</td></tr></table></blockquote><blockquote><p><b>attributeEstimate</b></p><p><b>description</b>: </p><div><p>I-squared = 78%</p>
</div><p><b>type</b>: <span title="Codes:{http://terminology.hl7.org/CodeSystem/attribute-estimate-type 0000420}">I-squared</span></p><p><b>quantity</b>: 78 %<span style="background: LightGoldenRodYellow"> (Details: UCUM code% = '%')</span></p></blockquote><blockquote><p><b>modelCharacteristic</b></p><p><b>code</b>: <span title="Codes:{https://fevir.net/resources/CodeSystem/179423 defined-in-text}">Hazard ratios were log transformed, and the CI was converted to standard error = (upper limit − lower limit)/3.92 for 95% CI. In random effect models (DerSimonian and Laird), we analysed adjusted HR to generate pooled HRs for the association between bariatric surgery for outcome in comparison with controls. The pooled HRs were calculated using inverse-variance weighted averaging and were depicted in forest plots.</span></p></blockquote><blockquote><p><b>modelCharacteristic</b></p><p><b>code</b>: <span title="Codes:{http://hl7.org/fhir/statistic-model-code metaAnalysis}">Meta-analysis</span></p></blockquote><blockquote><p><b>modelCharacteristic</b></p><p><b>code</b>: <span title="Codes:{http://hl7.org/fhir/statistic-model-code effectsRandom}">Random-effects</span></p></blockquote></blockquote></div>
</text>
<url value="https://fevir.net/resources/Evidence/49328"/>
<identifier>
<type>
<coding>
<system value="http://terminology.hl7.org/CodeSystem/v2-0203"/>
<code value="ACSN"/>
<display value="Accession ID"/>
</coding>
<text value="FEvIR Object Identifier"/>
</type>
<system value="https://fevir.net"/>
<value value="49328"/>
<assigner>
<display value="Computable Publishing LLC"/>
</assigner>
</identifier>
<name value="AllCauseMortality2022metaAnalysis"/>
<title
value="ComparativeEvidence: All-cause mortality effect of bariatric surgery in 2022 meta-analysis"/>
<status value="active"/>
<date value="2022-09-19T21:27:50.801Z"/>
<publisher value="Computable Publishing LLC"/>
<contact>
<telecom>
<system value="email"/>
<value value="support@computablepublishing.com"/>
</telecom>
</contact>
<author>
<name value="Brian S. Alper"/>
</author>
<useContext>
<code>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="evidence-communication"/>
<display value="Evidence Communication"/>
</code>
<valueCodeableConcept>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="ComparativeEvidence"/>
<display value="ComparativeEvidence"/>
</coding>
</valueCodeableConcept>
</useContext>
<useContext>
<code>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="evidence-communication"/>
<display value="Evidence Communication"/>
</code>
<valueCodeableConcept>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="EvidenceSynthesisEvidence"/>
<display value="EvidenceSynthesisEvidence"/>
</coding>
</valueCodeableConcept>
</useContext>
<useContext>
<code>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="evidence-communication"/>
<display value="Evidence Communication"/>
</code>
<valueCodeableConcept>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="OutcomeMeasureEvidence"/>
<display value="OutcomeMeasureEvidence"/>
</coding>
</valueCodeableConcept>
</useContext>
<copyright value="https://creativecommons.org/licenses/by-nc-sa/4.0/"/>
<relatedArtifact>
<type value="derived-from"/>
<label value="data source"/>
<citation
value="Bariatric surgery and cardiovascular disease: a systematic review and meta-analysis [Journal Article]. Contributors: van Veldhuisen SL, Gorter TM, van Woerden G, de Boer RA, Rienstra M, Hazebroek EJ, van Veldhuisen DJ. In: European heart journal, PMID 35243488. Published March 04, 2022. Available at: https://pubmed.ncbi.nlm.nih.gov/35243488/."/>
<document>
<url
value="https://academic.oup.com/eurheartj/article/43/20/1955/6542137"/>
</document>
</relatedArtifact>
<relatedArtifact>
<type value="supported-with"/>
<classifier>
<text value="Citation Resource for the original article"/>
</classifier>
<display
value="Citation Resource for 2022 Systematic Review of bariatric surgery mortality effect - PMID 35243488"/>
<resourceReference>🔗
<reference value="Citation/33400"/>
<type value="Citation"/>
<display
value="StudyCitation: 2022 Systematic Review of bariatric surgery mortality effect 35243488"/>
</resourceReference>
</relatedArtifact>
<relatedArtifact>
<type value="cite-as"/>
<citation
value="ComparativeEvidence: All-cause mortality effect of bariatric surgery in 2022 meta-analysis [Evidence]. Contributors: Brian S. Alper [Authors/Creators]. In: Fast Evidence Interoperability Resources (FEvIR) Platform, FOI 49328. Revised 2022-09-19. Available at: https://fevir.net/resources/Evidence/49328. Computable resource at: https://fevir.net/resources/Evidence/49328."/>
</relatedArtifact>
<description
value="effect estimate for bariatric surgery on all-cause mortality pooled hazard ratio (HR) 0.55 (95% confidence interval 0.49 to 0.62; P < 0.001 vs. controls) in meta-analysis of 21 cohort studies with 133,524 patients after bariatric surgery and 263,478 obese controls"/>
<assertion
value="The present systematic review and meta-analysis suggests that bariatric surgery is associated with reduced all-cause and CV mortality."/>
<variableDefinition>
<description
value="obese, adult (age ≥18 years old) patients *NOTE: note.text is used artificially to support the EBMonFHIR Implementation Guide and the following content would more properly be found in a note.text element:* Studies were considered eligible if they were designed to study outcomes in obese patients who underwent a weight-loss surgical intervention in comparison with an age, sex, and BMI matched control group who did not undergo a weight-loss surgical intervention. We searched for randomized controlled trials, prospective or retrospective longitudinal cohort studies, and case–control studies. For the control group, all non-surgical treatment options for obesity (e.g. intensive lifestyle intervention, standard of care, or no specific therapy) were accepted. Studies were excluded if (i) patients were not matched for age, sex, and BMI; (ii) the presence of one or more outcome parameters of interest (e.g. HF, AF, coronary artery disease) was required for inclusion; or (iii) if study groups were not representative in relation to the general population of patients with obesity (e.g. patients could only be included in the presence of a specific comorbidity, for instance, end-stage renal disease). The third criterium did not apply to Type 2 diabetes, thus studies that only included patients with Type 2 diabetes could be eligible for inclusion."/>
<variableRole value="population"/>
<intended>🔗
<reference value="Group/171819"/>
<type value="Group"/>
<display
value="StudyEligibilityCriteria: Obese patients ≥ 18 years old"/>
</intended>
</variableDefinition>
<variableDefinition>
<description
value="comparison groups of bariatric surgery vs. no bariatric surgery *NOTE: note.text is used artificially to support the EBMonFHIR Implementation Guide and the following content would more properly be found in a note.text element:* As the control group (observed reference exposure) was defined differently in each study, the intended reference exposure is described as the absence of the intended exposure (Bariatric Surgery)."/>
<variableRole value="exposure"/>
<comparatorCategory value="no bariatric surgery"/>
<intended>🔗
<reference value="EvidenceVariable/172427"/>
<type value="EvidenceVariable"/>
<display
value="GroupAssignment: Bariatric Surgery vs. no bariatric surgery"/>
</intended>
</variableDefinition>
<variableDefinition>
<description
value="All-cause mortality *NOTE: note.text is used artificially to support the EBMonFHIR Implementation Guide and the following content would more properly be found in a note.text element:* The observed element can reference an EvidenceVariable Resource that defines the outcome measured through structured characteristics. For example, “Mean difference in HbA1c at 12 months” or “Mean difference in HbA1c at end of study”. The structured characteristics can be references to the Evidence instances for each of the included studies, in which case this is a direct link to the dataset used for analysis. The intended element can reference an EvidenceVariable Resource that expresses the outcome intended for evidence application through structured characteristics. The structured characteristics could be used to express the SR eligibility criteria for study outcomes (as a subset of eligibility criteria for studies)."/>
<variableRole value="outcome"/>
<observed>
<display
value="We searched for randomized controlled trials, prospective or retrospective longitudinal cohort studies, and case–control studies. For the control group, all non-surgical treatment options for obesity (e.g. intensive lifestyle intervention, standard of care, or no specific therapy) were accepted. Studies were excluded if (i) patients were not matched for age, sex, and BMI; (ii) the presence of one or more outcome parameters of interest (e.g. HF, AF, coronary artery disease) was required for inclusion; or (iii) if study groups were not representative in relation to the general population of patients with obesity (e.g. patients could only be included in the presence of a specific comorbidity, for instance, end-stage renal disease). The third criterium did not apply to Type 2 diabetes, thus studies that only included patients with Type 2 diabetes could be eligible for inclusion."/>
</observed>
<intended>🔗
<reference value="EvidenceVariable/49217"/>
<type value="EvidenceVariable"/>
<display value="OutcomeVariable: All-cause mortality"/>
</intended>
</variableDefinition>
<synthesisType>
<coding>
<system value="http://terminology.hl7.org/CodeSystem/synthesis-type"/>
<version value="3.1.0"/>
<code value="std-MA"/>
<display value="summary data meta-analysis"/>
</coding>
</synthesisType>
<studyDesign>
<coding>
<system value="http://hl7.org/fhir/study-design"/>
<version value="5.0.0-cibuild"/>
<code value="SEVCO:01002"/>
<display value="Observational research"/>
</coding>
</studyDesign>
<studyDesign>
<coding>
<system value="http://hl7.org/fhir/study-design"/>
<version value="5.0.0-cibuild"/>
<code value="SEVCO:01011"/>
<display value="Parallel cohort design"/>
</coding>
</studyDesign>
<studyDesign>
<coding>
<system value="http://hl7.org/fhir/study-design"/>
<version value="5.0.0-cibuild"/>
<code value="SEVCO:01014"/>
<display value="Matching for comparison"/>
</coding>
</studyDesign>
<statistic>
<description
value="pooled hazard ratio (HR) 0.55 (95% confidence interval 0.49 to 0.62; P < 0.001 vs. controls) in meta-analysis of 21 cohort studies with 133,524 patients after bariatric surgery and 263,478 obese controls"/>
<note>
<text
value="heterogeneity: Tau2 = 0.06; Chi2 = 105.14; df = 23 (P < 0.00001); I2 = 78%"/>
</note>
<note>
<text value="test for overall effect z = 9.41 (p < 0.00001)"/>
</note>
<statisticType>
<coding>
<system value="http://terminology.hl7.org/CodeSystem/statistic-type"/>
<code value="C93150"/>
<display value="Hazard Ratio"/>
<userSelected value="true"/>
</coding>
</statisticType>
<quantity>
<value value="0.55"/>
</quantity>
<sampleSize>
<description
value="21 cohort studies with 133,524 patients after bariatric surgery and 263,478 obese controls"/>
<numberOfStudies value="21"/>
<numberOfParticipants value="397002"/>
</sampleSize>
<attributeEstimate>
<description value="95% confidence interval 0.49 to 0.62"/>
<type>
<coding>
<system
value="http://terminology.hl7.org/CodeSystem/attribute-estimate-type"/>
<code value="C53324"/>
<display value="Confidence interval"/>
</coding>
</type>
<level value="0.95"/>
<range>
<low>
<value value="0.49"/>
</low>
<high>
<value value="0.62"/>
</high>
</range>
</attributeEstimate>
<attributeEstimate>
<description value="z = 9.41"/>
<type>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="defined-in-text"/>
<display value="Defined in text"/>
</coding>
<text value="Z-score"/>
</type>
<quantity>
<value value="9.41"/>
</quantity>
</attributeEstimate>
<attributeEstimate>
<description value="p < 0.00001"/>
<type>
<coding>
<system
value="http://terminology.hl7.org/CodeSystem/attribute-estimate-type"/>
<code value="C44185"/>
<display value="P-value"/>
</coding>
</type>
<quantity>
<value value="1e-05"/>
<comparator value="<"/>
</quantity>
</attributeEstimate>
<attributeEstimate>
<description value="Tau squared = 0.06"/>
<type>
<coding>
<system
value="http://terminology.hl7.org/CodeSystem/attribute-estimate-type"/>
<code value="0000421"/>
<display value="Tau squared"/>
</coding>
</type>
<quantity>
<value value="0.06"/>
</quantity>
</attributeEstimate>
<attributeEstimate>
<description
value="Chi square for homogeneity 105.14, df 23 (p < 0.00001)"/>
<type>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="defined-in-text"/>
<display value="Defined in text"/>
</coding>
<text value="Chi square for homogeneity"/>
</type>
<quantity>
<value value="105.14"/>
</quantity>
<attributeEstimate>
<description value="degrees of freedom (df) = 23"/>
<type>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="defined-in-text"/>
<display value="Defined in text"/>
</coding>
<text value="Degrees of Freedom"/>
</type>
<quantity>
<value value="23"/>
</quantity>
</attributeEstimate>
<attributeEstimate>
<description value="p < 0.00001"/>
<type>
<coding>
<system
value="http://terminology.hl7.org/CodeSystem/attribute-estimate-type"/>
<code value="C44185"/>
<display value="P-value"/>
</coding>
</type>
<quantity>
<value value="1e-05"/>
<comparator value="<"/>
</quantity>
</attributeEstimate>
</attributeEstimate>
<attributeEstimate>
<description value="I-squared = 78%"/>
<type>
<coding>
<system
value="http://terminology.hl7.org/CodeSystem/attribute-estimate-type"/>
<code value="0000420"/>
<display value="I-squared"/>
</coding>
</type>
<quantity>
<value value="78"/>
<unit value="%"/>
<system value="http://unitsofmeasure.org"/>
<code value="%"/>
</quantity>
</attributeEstimate>
<modelCharacteristic>
<code>
<coding>
<system value="https://fevir.net/resources/CodeSystem/179423"/>
<code value="defined-in-text"/>
<display value="Defined in text"/>
</coding>
<text
value="Hazard ratios were log transformed, and the CI was converted to standard error = (upper limit − lower limit)/3.92 for 95% CI. In random effect models (DerSimonian and Laird), we analysed adjusted HR to generate pooled HRs for the association between bariatric surgery for outcome in comparison with controls. The pooled HRs were calculated using inverse-variance weighted averaging and were depicted in forest plots."/>
</code>
</modelCharacteristic>
<modelCharacteristic>
<code>
<coding>
<system value="http://hl7.org/fhir/statistic-model-code"/>
<code value="metaAnalysis"/>
<display value="Meta-analysis"/>
</coding>
</code>
</modelCharacteristic>
<modelCharacteristic>
<code>
<coding>
<system value="http://hl7.org/fhir/statistic-model-code"/>
<code value="effectsRandom"/>
<display value="Random-effects"/>
</coding>
</code>
</modelCharacteristic>
</statistic>
</Evidence>