{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T17:52:08Z","timestamp":1776102728493,"version":"3.50.1"},"reference-count":24,"publisher":"BMJ","issue":"4","license":[{"start":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T00:00:00Z","timestamp":1776038400000},"content-version":"unspecified","delay-in-days":12,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2026,3,22]]},"published-print":{"date-parts":[[2026,4]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>The objective of this study was to investigate the utility of the days alive and out of hospital (DAOH) metric within a cohort of patients undergoing burr-hole drainage of a chronic subdural haematoma (CSDH). We evaluate the validity of the DAOH metric in a national CSDH cohort and examine how the DAOH metric compares to its constituent outcomes (mortality and hospital bed days) at an organisational level.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Retrospective cohort study using Hospital Episode Statistics data linked to the national death registry to identify patients who underwent burr-hole drainage of CSDH in English National Health Service neurosurgical units between 1 April 2013 and 31 March 2020. Construct validity was assessed by measuring the patterns of DAOH across categories of known perioperative risk factors. Variation between units in the risk-adjusted values for DAOH, postoperative mortality and days in hospital was explored using funnel plots. Linear regression and logistic regression were used to derive the risk-adjusted rates.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Overall, 16\u2009450 patients who underwent at least one burr-hole drainage of CSDH were identified during the time period. The median 30-day DAOH was 16 (IQR, 0\u201324); the median for the 90-day DAOH was 74 (42\u201384), and was better at measuring the complete stay associated with the index admission. Worse 90-day DAOH values were associated with older age, increasing comorbidities and greater frailty. Risk-adjusted 90-day DAOH values for neurosurgical units varied more markedly than for its constituent outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The 90-day DAOH looks to be a valid outcome metric for patients undergoing burr-hole drainage for CSDH that is feasible to derive using national hospital data. Future work should explore how to estimate a minimally important clinical difference for DAOH and evaluate its utility as an outcome measure.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2025-114095","type":"journal-article","created":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T16:50:25Z","timestamp":1776099025000},"page":"e114095","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Days alive and out of hospital after burr-hole drainage for chronic subdural haematoma: a national cohort study using Hospital Episode Statistics in England"],"prefix":"10.1136","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-4140-1452","authenticated-orcid":false,"given":"Daniel","family":"Thompson","sequence":"first","affiliation":[{"name":"Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK"},{"name":"Department of Neurosurgery, NHS North Bristol NHS Trust, Bristol, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5746-0129","authenticated-orcid":false,"given":"Adam","family":"Wahba","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Royal Hallamshire Hospital, Sheffield, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Benjamin","family":"Davies","sequence":"additional","affiliation":[{"name":"Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adam","family":"Williams","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, NHS North Bristol NHS Trust, Bristol, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2796-1835","authenticated-orcid":false,"given":"Peter John","family":"Hutchinson","sequence":"additional","affiliation":[{"name":"Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2778-5226","authenticated-orcid":false,"given":"Daniel","family":"Stubbs","sequence":"additional","affiliation":[{"name":"Perioperative, Acute, Critical, and Emergency Care Section, Department of Medicine, University of Cambridge, Cambridge, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adel","family":"Helmy","sequence":"additional","affiliation":[{"name":"Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David A","family":"Cromwell","sequence":"additional","affiliation":[{"name":"Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, 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