Quality of Life: An Important Metric in Chronic Conditions

The World Health Organization (WHO) defines health as “not merely the absence of disease or infirmity, but a state of complete physical, mental, and social well-being.”¹ However, the definition of quality of life (QOL) is more complex.¹ According to the WHO, quality of life is defined as “individuals’ perceptions of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns.”¹ It can be summarized as the feeling of overall life satisfaction.² The evaluation of QOL involves a complex set of interacting objective and subjective factors.¹ 

The past few decades have seen an increasing predominance of chronic disorders.³ In general, chronic diseases are slow in progression, long in duration, and require medical treatment.³ The majority of chronic diseases hold the potential to worsen the overall health of patients by limiting their capacity to live well and their functional status.³ Among the most common chronic conditions are cancer, heart disease, stroke, diabetes, HIV, bowel disease, renal disease, and diseases of the central nervous system.³ The literature in health psychology generally supports the claim that chronic disease disrupts an individual’s day-to-day living and that this disruption can be measured in terms of its impact on an individual’s quality of life.³  

Quality of life is assessed either by interview or questionnaire.³ Interview methods utilize open-ended or semi-structured methods that can be helpful in uncovering the experiences of the patients.³ Questionnaires typically fall into two main categories: (1) generic questionnaires, which are used to evaluate QOL in different populations or (2) specific ones, which are used to analyze QOL in patients with specific conditions.³ Some assessments that are commonly used in studies of chronic disease are the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), the Nottingham Health Profile (NHP), and the EuroQol (EQ-5D).^3,4 

In the context of chronic disease, quality of life can be studied as either a primary or secondary outcome.³ It is an important metric in evaluating the impact of a disease and any medical intervention.⁴ An improvement is considered to be an essential primary outcome and determinant of therapeutic benefit.^3,4 However, this metric is also a useful secondary outcome of research studies that provide data on the impact of therapeutic interventions.⁴ 

In studies of breast cancer survivors, researchers  have generally found a lower reported quality of life compared to control participants.⁵ This trend is associated with more limitations in activities of daily living, issues with sexual functioning, decreased self-esteem, and unhealthy coping strategies.^5,6 One factor that was found to have an influence on the QOL of breast cancer survivors was the type of surgery, with mastectomies  being associated with poorer outcomes compared to breast conserving treatment.⁷ 

Moreover, a number of researchers have investigated the quality of life in patients with heart failure.³ Patients with heart failure have frequently reported significant impairments beyond physical functioning.⁸ Importantly, quality of life measurements in patients with heart failure is a predictor of mortality and morbidity after cardiac procedures.⁸ This metric should be a key consideration in clinical settings when making treatment decisions.

References 

1. Megari K. (2013). Quality of Life in Chronic Disease Patients. Health psychology research, 1(3), e27. doi:10.4081/hpr.2013.e27 

2. Meeberg, G. (1993). Quality of life: a concept analysis. Journal of Advanced Nursing, 18(1), 32-38. doi:10.1046/j.1365-2648.1993.18010032.x 

3. Staquet, M. J., Hays, R. D., & Fayers, P. M. (1998). Quality of life assessment in clinical trials: methods and practice. 

4. EuroQol – a new facility for the measurement of health-related quality of life. (1990). Health Policy, 16(3), 199-208. doi:10.1016/0168-8510(90)90421-9 

5. Richardson, L., Wingo, P., Zack, M., Zahran, H., & King, J. (2008). Health-related quality of life in cancer survivors between ages 20 and 64 years. Cancer, 112(6), 1380-1389. doi:10.1002/cncr.23291 

6. Hewitt, M., Rowland, J., & Yancik, R. (2003). Cancer Survivors in the United States: Age, Health, and Disability. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 58(1), M82-M91. doi:10.1093/gerona/58.1.m82 

7. Ohsumi, S., Shimozuma, K., Morita, S., Hara, F., Takabatake, D., & Takashima, S. et al. (2009). Factors Associated with Health-related Quality-of-life in Breast Cancer Survivors: Influence of the Type of Surgery. Japanese Journal of Clinical Oncology, 39(8), 491-496. doi:10.1093/jjco/hyp060 

8. Fukuoka, Y., Lindgren, T., Rankin, S., Cooper, B., & Carroll, D. (2007). Cluster analysis: a useful technique to identify elderly cardiac patients at risk for poor quality of life. Quality of Life Research, 16(10), 1655-1663. doi:10.1007/s11136-007-9272-7