title: Impact of neurocognitive deficits on patient-proxy agreement regarding health-related quality of life in low-grade glioma patients.
abstract: Clinical trials in glioma patients with neurocognitive deficits face challenges due to lacking or unreliable patient self-reports on their health-related quality of life (HRQOL). Patient-proxy data could help solve this issue. We determined whether patient-proxy concordance levels were affected by patients' neurocognitive functioning.
  
  
  
  Patient and patient-by-proxy HRQOL ratings were assessed via SF-36 and EORTC QLQ-BN20, respectively, in 246 patients. Data on neurocognitive functioning were collected on a subgroup of 195 patients. Patient-proxy agreement was measured using the Bland-Altman limit of agreement, the mean difference, the concordance correlation coefficient (CCC), and the percentage difference (PD, ±0, 5, or 10 points). We defined patients to be cognitively impaired (n = 66) or cognitively intact (n = 129) based on their neurocognitive performance.
  
  
  
  Patients rated their physical function and general health to be better than their proxies did, while at the same time, patients reported more visual disorders, communication deficits, itchy skin, and problems with bladder control. The cognitively impaired subgroup reported poorer physical functioning, more visual disorders, headaches, itchy skin, and issues with bladder control. In the cognitively intact group, no statistical significant differences were observed between patients and proxies. Not surprisingly, Bland-Altman plots revealed a high agreement between the patient and patient-by-proxy rating in all HRQOL domains ranging from 95 to 99 %. The CCC was fairly high in all HRQOL domains (0.37-0.80), and the percentage of perfect agreement (PD ± 0) ranged from 8.5 to 76.8 %. In the cognitively impaired patients, the mean difference between patients and proxies was overall larger, and accordingly, agreement based on Bland-Altman plots was lower.
  
  
  
  The level of agreement between patient and patient-by-proxy ratings of low-grade glioma patients' HRQOL is generally high. However, patient-proxy agreement is lower in patients with neurocognitive deficits than in patients without neurocognitive deficits.
authors.affiliation: Quality of Life Department, European Organisation for Research and Treatment of Cancer (EORTC), Brussels, Belgium.
authors.forename: Divine E
authors.initials: DE
authors.lastname: Ediebah
authors.affiliation: Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jaap C
authors.initials: JC
authors.lastname: Reijneveld
authors.affiliation: Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.|Department of Neurology, Medical Center Haaglanden, The Hague, The Netherlands.
authors.forename: Martin J B
authors.initials: MJ
authors.lastname: Taphoorn
authors.affiliation: Quality of Life Department, European Organisation for Research and Treatment of Cancer (EORTC), Brussels, Belgium.
authors.forename: Corneel
authors.initials: C
authors.lastname: Coens
authors.affiliation: Quality of Life Department, European Organisation for Research and Treatment of Cancer (EORTC), Brussels, Belgium.
authors.forename: Efstathios
authors.initials: E
authors.lastname: Zikos
authors.affiliation: Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Neil K
authors.initials: NK
authors.lastname: Aaronson
authors.affiliation: Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Heimans
authors.affiliation: Quality of Life Department, European Organisation for Research and Treatment of Cancer (EORTC), Brussels, Belgium.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bottomley
authors.affiliation: Department of Medical Psychology - B7D349, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands. m.klein@vumc.nl.
authors.forename: Martin
authors.initials: M
authors.lastname: Klein
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000150:complications* / Q000473:pathology; D060825:Cognitive Dysfunction / Q000150:complications / Q000523:psychology*; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D005260:Female; D005910:Glioma / Q000150:complications* / Q000473:pathology; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009426:Netherlands; D019727:Proxy; D011788:Quality of Life; D057566:Self Report
keywords: Brain tumor; Health-related quality of life; Neurocognitive deficits; Proxy ratings