title: Identification and prediction of health-related quality of life trajectories after a prostate cancer diagnosis.
abstract: The aim of our study was to identify physical and mental health-related quality of life (HRQoL) trajectories after a prostate cancer diagnosis and systematically characterize trajectories by behaviours and prognostic factors. Prostate cancer survivors (n = 817) diagnosed between 1997 and 2000 were recruited between 2000 and 2002 into a prospective repeated measurements study. Behavioural/prognostic data were collected through in-person interviews and questionnaires. HRQoL was collected at three post-diagnosis time-points, approximately 2 years apart using the Short Form (SF)-36 validated questionnaire. To identify physical and mental HRQoL trajectories, group-based trajectory modelling was undertaken. Differences between groups were evaluated by assessing influential dropouts (mortality/poor health), behavioural/prognostic factors at diagnosis or during the follow-up. Three trajectories of physical HRQoL were identified including: average-maintaining HRQoL (32.2%), low-declining HRQoL (40.5%) and very low-maintaining HRQoL (27.3%). In addition, three trajectories for mental HRQoL were identified: average-increasing HRQoL (66.5%), above average-declining HRQoL (19.7%) and low-increasing HRQoL (13.8%). In both physical and mental HRQoL, dropout from mortality/poor health differed between trajectories, thus confirming HRQoL and mortality were related. Furthermore, increased Charlson comorbidity index score was consistently associated with physical and mental HRQoL group membership relative to average maintaining groups, while behaviours such as time-varying physical activity was associated with physical HRQoL trajectories but not mental HRQoL trajectories. It was possible to define three trajectories of physical and mental HRQoL after prostate cancer. These data provide insights regarding means for identifying subgroups of prostate cancer survivors with lower or declining HRQoL after diagnosis whom could be targeted for interventions aimed at improving HRQoL.
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.|Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Farris
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.|Department of Mathematics and Statistics, University of Calgary, Calgary, Alberta, Canada.|Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Kopciuk
authors.affiliation: Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Kerry S
authors.initials: KS
authors.lastname: Courneya
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.|Department of Mathematics and Statistics, University of Calgary, Calgary, Alberta, Canada.|Population, Public & Indigenous Health, Alberta Health Services, Calgary, Alberta, Canada.
authors.forename: S Elizabeth
authors.initials: SE
authors.lastname: McGregor
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Calgary, Alberta, Canada.|Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.|Department of Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Friedenreich
mesh_terms: D000368:Aged; D000416:Alberta; D015438:Health Behavior; D006304:Health Status; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D017741:Survivors
keywords: group-based trajectory; health-related quality of life; mixed model; prostate cancer