Relation between Severe Illness and Non-Completion of Quality-of-Life Questionnaires by Patients with Rectal Cancer

Abstract

Quality of life (QoL) is an important outcome measure in clinical studies, but interpretation is hindered by incompleteness of data. We addressed this issue in a population-based cohort study of 146 patients with newly diagnosed rectal cancer. QoL was assessed by means of European Organization for the Research and Treatment of Cancer questionnaires at discharge from hospital after primary treatment and then every 3 months for 2 years. In parallel, objective clinical data were documented. Analyses were conducted in three steps: participants versus non-participants with QoL-assessment; poor compliers who filled in only one or two questionnaires (n=20) versus good compliers who filled in all or nearly all questionnaires (n=18); and the proportion of missing forms and critical (very poor) QoL scores in risk patients versus non-risk patients over the course of 2 years. Non-participants and poor compliers were older, were more likely to receive palliative (rather than curative) treatment, and had worse scores for physical status. Tumour progression and therapeutic interventions were more frequent in poor compliers than in good-compliers. Patients with risk factors (age 475 years, poor physical status, palliative treatment) were more likely to have missing questionnaires and critical QoL scores in respect of physical functioning and global quality of life over the course of 2 years. Missing values for QoL have clinical as well as methodological implications, because QoL scores can enhance a clinician's insight. Unwillingness to fill in a questionnaire is an indicator of serious illness. Studies that report sample statistics without specifying compliance rates and the characteristics of non-compliers will give a misleadingly positive picture.

Understanding quality of life in patients with colorectal cancer: comparison of data from a randomised controlled trial, a population based cohort study and the norm reference population

“…Age, high ASA Scores (III/IV) and treatment with palliative intent were identified as risk factors for non-compliance with QoL assessment. These risk factors characterising non-compliant patients were also associated with poor scores for quality of life [10]. Mean scores therefore may imply overestimation of sample QoL, depending on the amount of and reasons for missing values.…”

“…Both discrepancies could be due to a selection bias [20 -23]. In a previous analysis of the cohort study results we addressed the problem of missing data [10]. Age, high ASA Scores (III/IV) and treatment with palliative intent were identified as risk factors for non-compliance with QoL assessment.…”

Early self-reported impairments in arm functioning of primary breast cancer patients predict late side effects of axillary lymph node dissection: results from a population-based cohort study

“…AUCs could be computed for n = 138 patients and differences in baseline characteristics between these patients and the rest of the cohort were computed using v 2 -tests and t-test, where appropriate [22]. The AUC methodology has been described in various publications [23,24,25] .The AUC score was subjected to multiple regression analyses (performed for the whole sample and the subgroup of lymph node negative patients), entering variables that are clinically plausible predictors of arm morbidity: number of dissected lymph nodes, age, UICC stage, type of operation, and radiation therapy.…”

Survival chances and psychological aspects of quality of life in patients with localized early stage breast cancer

“…The completion rate for pTis was 60/110 = 54.5 %; for pT1a,b 157/290 = 54.1 %; for pT1c 317/655 = 48.4 %; and for pT2 156/290 = 53.8 %. The completion rates of the 4 groups were comparable and confounding effects due to missing forms seemed unlikely [23].…”