Cumulative Incidence of Second Major Abdominal Surgery Crohnʼs Disease: A Systematic Review and Meta-analysis of Population-based Studies
Bibliographic record
Abstract
Purpose: Approximately 70-80% of Crohn's disease (CD) patients will undergo at least one surgery in their lifetime. The risk of second surgery in Crohn's disease, however, is not well characterized. We per-formed a systematic review and meta-analysis to establish the 5 and 10-year cumulative risk of second major abdominal surgery in patients with CD who already had a first surgery. Methods: We conducted a systematic literature search of Medline (1948-2013), EMBASE (1980-2013), and conference abstracts (2011-2012) to identify 8,300 unique abstracts that contained surgical information on inflammatory bowel disease or CD. Studies were included if they were population-based and reported a 5- or 10-year cumulative risk of second surgery in patients with CD. Two reviewers independently identified and abstracted data. Risk estimates and corresponding 95% confidence intervals (CI) were separately pooled using random-effects models 5 and 10 years after first surgery. Heterogeneity between studies was assessed using Cochran Q statistic. Publication bias was assessed by the Begg's rank correlation test. Results: The search yielded five original research articles (N=6,247 incident cases) that were conducted from 1970-2008. Two studies provided estimates for pediatric populations, and three for all ages. The 5- and 10-year cumulative risk of second surgery were 24.2% (95% confidence interval [CI] 21.0-27.8%) and 36.2% (95% CI 32.1-40.9%), respectively (Figure 1). Significant between-study heterogeneity was observed for the 10-year estimates (Q=10.5, p-value: 0.03), but not for the 5-year estimate (Q=8.3, p-value: 0.08). For studies restricted to pediatric populations, the 5- and 10-year second surgery estimates were 21.5% (95% CI 14.9-31.1%) and 33.5% (95% CI 27.4-40.9%). There was no significant heterogeneity between the 5- (Q=3.5; p-value: 0.06) or 10-year pediatric estimates (Q=2.1, p-value: 0.15). Publication bias was not detected (p-values > 0.05).FigureConclusion: Approximately one in three CD patients underwent a second major abdominal surgery within 10 years of first surgery. However, second surgery predominantly occurred within 5 years of the first operation. Second surgery estimates are lower in studies restricted to pediatric populations than populations of all ages. Future studies should evaluate whether second surgery rates have changed over time.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.018 | 0.041 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.021 | 0.041 |
| Bibliometrics | 0.011 | 0.011 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".