P405 5-ASA prescription trends over time in inflammatory bowel disease 1996 to 2015–A UK population-based study
Bibliographic record
Abstract
5-Aminosalicylates (5-ASA) are commonly prescribed for inflammatory bowel disease (IBD). Whilst they are effective in mild–moderate ulcerative colitis (UC), evidence for their benefit in Crohn’s disease (CD) is controversial. Few data are available on the evolution of 5-ASA prescriptions over time, from a population level. 5-ASA prescription trends in prevalent IBD patients in The Health Improvement Network (THIN) UK primary care database were evaluated retrospectively across five 4-year periods (era 1–5) between 1996 and 2015. The proportion of patients prescribed 5-ASA at any time of their disease, and within 1 year of IBD diagnosis was stratified by IBD type, 5-ASA type and age group (015–<18, ≥18–<65, ≥5, years). Prolonged use was defined as continuous use for ≥ye months. Chi-squared test for trend was used to evaluate differences in prescription trends. Trends were qualitatively assessed relative to the publication of new evidence and guidelines. Prevalence of 5-ASA prescriptions over time and total number of patients by each era are shown in Figure 1. Prevalence of 5-ASA prescriptions among patients with ulcerative colitis and Crohn’s disease from 1996 to 2015. Demographic characteristics were similar over time: 48–51% of UC and 56–58% CD patients were female; the range of mean age of UC patients was 50–56 years and 46–50 years in CD. Current smoking status declined in UC (12–8%) and CD (32–20%) from era 1 to 5. For UC, 5-ASA prescriptions declined from 83% in era 1 to 71% in era 5 (p < 0.001). The use of mesalazine remained stable from era 1 to 5 (63–65%, p = 0.151). In UC patients aged 12–18 5-ASA use remained similar over time, whereas in >65-year-old 5-ASA use declined (83–69%, p < 0.001). Initiation of 5-ASA within 1 year of UC diagnosis increased from era 1 to 5 (35% to 58%, p < 0.001). For CD, 5-ASA prescriptions declined from era 1 to 5 (64% to 45%, p < 0.001). The use of mesalazine increased from 53% in era 1 to 56% in era 2, then declined to 41% in era 5. The proportion of 5-ASA prescriptions decreased in CD patients aged 12–18 (77–45%, p = 0.036) and >65 years (60–49%, p < 0.001). Initiation of 5-ASA within 1 year of CD diagnosis increased from 38% to 58% from era 1 to 5 (p < 0.001). Prolonged 5-ASA use was 35% in UC and 31% in CD in era 5. 5-ASA remains a highly used treatment for UC and CD in the UK. Almost one-third of IBD patients had a prolonged use of 5-ASA. Despite lack of strong evidence for their benefit in CD, half of patients are still prescribed 5-ASA for CD, indicating a disparity between evidence base and clinical prescribing practice.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.007 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".