title: A multilevel regression of patient-reported outcome measures after varicose vein treatment in England.
abstract: BACKGROUND
  The relationship between patient and hospital characteristics and their influence on quality of life (QoL) variance following varicose vein treatment is little understood. Whilst Patient-reported outcome measures (PROMs) can record postoperative outcomes, the actual comparison of PROMs between hospitals can be misleading when the clustered nature of varicose vein care is overlooked. Multilevel models can accommodate hierarchical data and therefore can provide a more accurate reflection of the relationship between patients and hospitals when investigating postoperative outcomes.
  
  
  METHODS
  A multilevel model of PROMs was developed to analyse the relationship of patient characteristics (gender, age), postoperative outcomes (complications, postoperative satisfaction, treatment success) and hospital type (operative volume and if private or NHS institution) with the change in Aberdeen Varicose Vein Score (AVVQ) six months after varicose vein treatment.
  
  
  RESULTS
  Between April 2010 and July 2014, some 24,460 PROMs from 162 hospitals were analysed. Whilst the majority of variance in AVVQ improvement was due to patient factors, a small but statistically significant amount of variance was detected due to differences between hospitals. Multilevel regression revealed that females saw a greater improvement in AVVQ, as did those who reported greater levels of treatment success and satisfaction. Patient age, complications, intervention, readmission, hospital size and hospital type were not significantly associated with AVVQ improvement.
  
  
  CONCLUSIONS
  Although QoL is intrinsically tied to an individual, hospitals can provide a small but potentially important benefit in AVVQ improvement following vein treatment. A patient-centred approach is therefore recommended to optimise patient outcomes.
authors.affiliation: Academic Vascular Surgery Unit, Hull Royal Infirmary, Hull, Humberside, UK Jelsheikha@doctors.org.uk.
authors.forename: Joseph
authors.initials: J
authors.lastname: El-Sheikha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011788:Quality of Life; D057566:Self Report; D014648:Varicose Veins / Q000453:epidemiology* / Q000628:therapy*
keywords: Multilevel model; PROMs; patient-reported outcome measures; varicose veins