Quality of life (QoL) assessment - the when, what, how, and who of it.
Updated: May 28, 2020
Assessment of quality of life, and assigning a quality of life (QoL) score, is becoming an increasingly popular tool in various spheres of veterinary medicine. In fact, Yeates and Main (2009), probably put it best in stating that assessing the quality of life of the companion animals that we treat is the ‘central part of veterinary practice’. From 'itchy skin' cases to oncology cases, QoL assessment has been implemented as both a monitoring tool and a means of facilitating end-of-life decision making.
Old school or new and cool?
QoL assessment, albeit a topic that has popped up in several journal articles over the past couple of decades, is still fairly novel. This most likely stems from the fact that there is limited guidance in the formulation of QoL assessments (or tools), and in instances where guidance does exist, this is often based on QoL assessment in various disciplines of human medicine, ethics, and philosophy. Unfortunately, this doesn't always translate so well for our four-legged patients.
Simply put, QoL assessment is multifaceted, often complex, and unfortunately, somewhat controversial.
Let’s dive into some reasons as to why controversy may surround QoL assessment. Firstly, many of the interventions that we make under the claim of "trying to improve an animals QoL", are driven by the goal of improving client satisfaction, rather than primarily bettering the life of the animal in question. The best example is that of addressing the issue of incontinence. Primarily, rectifying or minimizing the occurrence of incontinence episodes is to limit client inconvenience in having to clean up such mishaps, with hygiene probably best considered an added benefit. Secondly, how we monitor QoL or changes in QoL, is sometimes (inappropriately so) based on biological parameters. For example, chasing improvements in certain markers of disease severity, in the hope that improvement in these equals improvement in QoL, is a common mistake. What is the cost to the animal in question, with a polypharmacy approach and repeated testing?
So, before we get ahead of ourselves, how do we define 'quality of life' or QoL. There's more than one way to sheer a sheep...
QoL has been defined as the following:
‘An individual’s satisfaction with its physical and psychological health, its physical and social environment and its ability to interact with that environment’ (Belshaw et al. 2015)
'The subjective and dynamic evaluation by the individual of its circumstances (internal and external) and the extent to which these meet its expectations (that may be innate or learned and that may or may not include anticipation of future events), which results in, or includes, an affective (emotional) response to those circumstances (the evaluation may be a conscious or unconscious process, with a complexity appropriate to the cognitive capacity of the individual)' (Wiseman-Orr et al. 2006)
It doesn't take a rocket scientist to figure out that some parts of the definitions above may be open to interpretation, especially with veterinary patients. While it seems logical that there should be at least some useful application of QoL assessment in veterinary science, unfortunately, the validity of QoL scores for widespread and even routine use, needs some more fleshing out and further research. Yeates and Main compiled a great review article on the topic, and discussed four important questions to address before tackling the concept of QoL assessment, namely:
1) When to assess QoL?
2) What to assess?
3) How to perform assessments?
4) Who can best assess it?
After answering the four questions above, its a good idea to have an approach in mind as to how you would carry out a QoL assessment. The review by Yeates and Main (if it's not clear from all the mutterings above, I thoroughly recommend reading their article - link below) also provides some approaches that could potentially be instituted by you, in a clinic environment, if you're looking to incorporate QoL assessment into your day-to-day practice. The approaches listed include:
1) Three concepts framework
2) Five Freedoms
3) Input assessment
4) Affective assessments
The Five Freedoms, as veterinarians, we are all probably very familiar with, but I would definitely recommend looking into the use of the "Three concepts framework", which may be a more holistic approach to QoL assessment as it addresses physical, mental, and natural conceptualizations of animal welfare.
Looking at things from a more practical standpoint, here are a few examples of current veterinary applications for QoL assessment, both in general practice and a research setting:
Atopic dermatitis and other skin diseases (Favrot et al. 2010; Noli et al. 2011)
Assessment of physical activity in dogs receiving chemotherapy (Helm et al. 2016)
Canine and feline cancer chemotherapy (Iliopoulou et al. 2013; Vols et al. 2016)
Canine cancer treatments (Giuffrida and Kerrigan 2014)
Canine lymphoma (Mellanby et al. 2002)
Feline lymphoma (Tzannes et al. 2008; Thornton et al. 2018)
Pain secondary to cancer (Yazbek et al. 2005)
Canine diabetes mellitus (Niessen et al. 2012)
Cardiac disease (Freeman et al. 2005)
Feline quality of life (Tatlock et al. 2017)
Osteoarthritis (Brown et al. 2007)
Quality of life assessment in kennelled dogs (Kiddie and Collins 2014)
Spinal cord injuries (Budke et al. 2008)
Unfortunately, the majority of the literature cited above documents studies involving dogs (and of course their owners), with fewer papers assessing QoL in feline patients. As mentioned above, QoL assessment is growing in popularity - so hopefully this changes, along with the scope of application - watch this space!
If you're keen to do some more reading on the topic, don't hesitate to reach out, and please find below a list of interesting articles that were consulted (some more thoroughly than others), for the compilation that is this blog post.
Adamelli S, Marinelli L, Normando S, Bono G. (2005) Owner and cat features influence the quality of life of the cat. Appl Anim Behav Sci, 90(1-2):89-98.
Belshaw Z, Asher L, Harvey ND, Dean RS. (2015) Quality of life assessment in domestic dogs: An evidence-based rapid review. Vet J, 206:203-212. Available online: https://www.sciencedirect.com/science/article/pii/S109002331500307X
Marinelli L, Adamelli S, Normando S, Bono G. (2007) Quality of life of the pet dog: Influence of owner and dog's characteristics. Appl Anim Behav Sci, 108(1-2):143-156. Available online:
Yeates J, Main D. (2009) Assessment of companion animal quality of life in veterinary practice
and research. J Small Anim Prac, 50:274-281. Available online: https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1748-5827.2009.00755.x