Measurement accuracy in assessing patient’s quality of life: to weight or not to weight domains of quality of life

Importance of and Satisfaction with Domains of Health-Related Quality of Life in Cancer Rehabilitation

Instruments for measuring health-related quality of life (HRQoL) generally do not consider the subjective importance of the dimensions they comprise. The aims of this study were to analyze the subjectively perceived importance of the dimension of HRQoL and to investigate their relationship to the satisfaction ratings with these dimensions. A total of 1108 participants enrolled in a cancer rehabilitation program were surveyed. Patients rated eight dimensions of HRQoL (physical functioning, autonomy, emotional stability, cognitive functioning, social relationships, vitality, absence of pain, and sleep quality), as well as global health in terms of how important those dimensions are to them, and how satisfied they are with them. The dimensions with the highest importance ratings were autonomy and social relationships. There were only small sex differences in the importance ratings, but younger patients rated health as being more important than older patients did. The correlations between the importance ratings and the satisfaction ratings of the specific HRQoL dimensions ranged from −0.06 to 0.40, and the correlation between importance and satisfaction for global health was 0.01. Importance ratings provide relevant information for health care professionals in addition to the HRQoL assessments in the context of cancer rehabilitation.

Structural differences in life satisfaction in a U.S. adult sample across age

OBJECTIVE

Many studies investigating age-related mean differences in life satisfaction disregard potential differences in the structure of the life satisfaction construct. Because developmental tasks at different life stages vary and thus the salience of specific life domains (e.g., health, finances, relationships, etc.) might differ, life satisfaction might differ between age groups in its underlying structure and meaning.

METHOD

To address this issue, we investigated the covariance structure of life satisfaction as measured by the Satisfaction with Life Scale (SWLS) and the domains of health satisfaction and financial satisfaction with local structural equation modeling. We analyzed data from 8341 U.S. citizens between the ages of 30 and 97 who participated in the Panel Study of Income Dynamics. Furthermore, we explored the association of respondents' health and financial status with life satisfaction.

RESULTS

Both the SWLS and domain items were found to be invariant across age. The health and financial status accounted for small proportions of variance in overall life satisfaction and the respective domain satisfactions significantly at all ages.

CONCLUSION

The current analysis indicates that across the adult age range, general life satisfaction is qualitatively the same, and health and financial satisfaction are equally integrated into overall life satisfaction.

The impact of occupational splash, sharps and needlestick injuries (SSNIs) on the quality of life of healthcare workers in a Kenyan university hospital

BACKGROUND

Infection as a consequence of splash sharps and needlestick injuries (SSNIs) is a hazard faced by healthcare workers. Little is known about the impact this has on quality of life particularly in countries where the risk of infection is high.

OBJECTIVE

This study aims to describe the impact SSNIs have on the quality of life of healthcare workers in Kenya, where blood borne illness prevalence is high.

METHODS

A hospital-wide survey of a facility in Nairobi was conducted. Data was collected online from at risk healthcare workers using Burckhardt and Anderson's Quality of Life Scale (QOLS) and a 10-item symptoms questionnaire.

RESULTS

Of the 416 participants, 192 (46.2%) had experienced SSNIs. Their mean QOLS scores were considerably lower than that predicted for a healthy population. The relationship between symptoms and QOLS scores showed a strong positive correlation (Pearson's r = 0.753). Tests of association between QOLS scores and SSNI type, anti-retroviral (ARV) drug use, educational level and staff cadre revealed significant association (p < 0.05). However, on key demographic variables, the association was non-dependent, indicating that the impact was felt similarly by many staff.

CONCLUSIONS

SSNIs clearly impact on healthcare workers quality of life. Hospital management should ensure measures are taken to reduce SSNIs and provide appropriate personal protection equipment. For staff experiencing an SSNI, psychological wellbeing should be assessed and appropriate expert help provided.

Individual Importance Weighting of Domain Satisfaction Ratings does Not Increase Validity

Bottom-up models of life satisfaction are based on the assumption that individuals judge the overall quality of their lives by aggregating information across various life domains, such as health, family, and income. This aggregation supposedly involves a weighting procedure because individuals care about different parts of their lives to varying degrees. Thus, composite measures of well-being should be more accurate if domain satisfaction scores are weighted by the importance that respondents assign to the respective domains. Previous studies have arrived at mixed conclusions about whether such a procedure actually works. In the present study, importance weighting was investigated in the Panel Study of Income Dynamics (PSID; N = 5,049). Both weighted composite scores and moderated regression analyses converged in producing the conclusion that individual importance weights did not result in higher correlations with the outcome variable, a global measure of life satisfaction. By contrast, using weights that vary normatively across domains (e.g., assigning a larger weight to family satisfaction than to housing satisfaction for all respondents) significantly increased the correlation with global life satisfaction (although incremental validity was rather humble). These results converge with findings from other fields such as self-concept research, where evidence for individual importance weighting seems elusive as best.

Composite scores in comparative effectiveness research: counterbalancing parsimony and dimensionality in patient-reported outcomes

When planning a comparative effectiveness study comparing disease-modifying treatments, competing demands influence choice of outcomes. Current practice emphasizes parsimony, although understanding multidimensional treatment impact can help to personalize medical decision-making. We discuss both sides of this 'tug of war'. We discuss the assumptions, advantages and drawbacks of composite scores and multidimensional outcomes. We describe possible solutions to the multiple comparison problem, including conceptual hierarchy distinctions, statistical approaches, 'real-world' benchmarks of effectiveness and subgroup analysis. We conclude that comparative effectiveness research should consider multiple outcome dimensions and compare different approaches that fit the individual context of study objectives.

The often overlooked issue of statistical power: this and other issues regarding assessing importance weighting in quality of life measures

In the area of quality of life research, researchers may ask respondents to rate importance as well as satisfaction of various life domains (such as job and health) and use importance ratings as weights to calculate overall, or global, life satisfaction. The practice of giving more important domains more weight, known as importance weighting, has not been without controversy. Several previous studies assessed importance weighting using the analytical approach of moderated regression. This study discusses major issues related to how importance weighting has been assessed. Specifically, this study highlights that studies on importance weighting without considering statistical power are prone to type II error, i.e., failing to reject the null hypothesis of no significant weighting effect when the null hypothesis is actually false. The sample size required for adequate statistical power to detect importance weighting functions appeared larger than most previous studies could offer.

The structure of psychological life satisfaction: insights from farmers and a general community sample in Australia

BACKGROUND

Psychological life satisfaction is a robust predictor of wellbeing. Public health measures to improve wellbeing would benefit from an understanding of how overall life satisfaction varies as a function of satisfaction with multiple life domains, an area that has been little explored. We examine a sample of drought-affected Australian farmers and a general community sample of Australians to investigate how domain satisfaction combines to form psychological satisfaction. In particular, we introduce a way of statistically testing for the presence of "supra-domains" of satisfaction to propose a novel way of examining the composition of psychological life satisfaction to gain insights for health promotion and policy.

METHODS

Covariance between different perceptions of life domain satisfaction was identified by conducting correlation, regression, and exploratory factor analyses on responses to the Personal Wellbeing Index. Structural equations modelling was then used to (a) validate satisfaction supra-domain constructs emerging from different perceptions of life domain satisfaction, and (b) model relationships between supra-domains and an explicit measure of psychological life satisfaction.

RESULTS

Perceived satisfaction with eight different life domains loaded onto a single unitary satisfaction construct adequately in each sample. However, in both samples, different domains better loaded onto two separate but correlated constructs ('supra-domains'): "satisfaction with connectedness" and "satisfaction with efficacy". Modelling reciprocal pathways between these supra-domains and an explicit measure of psychological life satisfaction revealed that efficacy mediated the link between connectedness and psychological satisfaction.

CONCLUSIONS

If satisfaction with connectedness underlies satisfaction with efficacy (and thus psychological satisfaction), a novel insight for health policy emerges: psychological life satisfaction, a vital part of wellbeing, can potentially be enhanced by strengthening individuals' connectedness to community. This may be particularly important and efficacious for vulnerable populations.