Health baseline comparisons and quality of life in people with cancer

Abstract

This programme of research involved the development of a new health psychology concept: health baseline comparisons (HBCs). This is defined as the comparative baselines used to assess subjective health status. The following broad research questions were tested: Which HBCs are adopted by individuals with cancer?; What are the implications of different HBCs for quality of life (QoL) and other types of well-being?; How stable are HBCs throughout a course of treatment? A mixed-methodology approach was adopted to address the research questions. Five studies were conducted, all but the initial pilot study involving a clinical sample of people with cancer. A questionnaire to measure the use of different HBCs was developed and pilot tested, before being used to examine HBCs in people with breast and prostate cancer. On further refining the HBC construct, the questionnaire was re-validated and used to explore HBCs in women undergoing chemotherapy for breast cancer. The extent to which HBCs predicted QoL and psychological well-being was also examined in these studies. The stability of HBCs was sought from the same women two-months post-chemotherapy, focusing on associations with QoL and emotional well-being. The cross-sectional and longitudinal findings obtained in the first four studies were supplemented by a series of semi-structured interviews with a purposive sample of women from the longitudinal study. Interview transcripts were analysed via interpretative phenomenological analysis. Five categories of health baselines emerged from this programme of research: social; social comparison; biological; illness-specific; and turning to others. Some evidence was found that HBCs can change over time or be affected by illness and its treatment. Some HBCs, particularly social comparison and illness-specific baselines, were found to be significant predictors of QoL and psychological well-being, but the variance accounted for in these outcomes was generally small. Although the HBC questionnaire had acceptable internal consistency and reflected the experiences of people during cancer treatment and in the survivorship period, evidence was also found that the type and pattern of HBCs are subject to individual differences. This indicates that assessment of the construct also requires a qualitative and personalised component. The implications of the findings for the development of interventions are discussed and ideas for future research explored.