It's standard to consider objective, measurable factors when evaluating and treating a patient—Is it running a fever? Are its liver enzyme activities high? Is it vomiting less frequently? But an animal's quality of life depends on more than physical parameters—it includes all aspects of an animal's life that matter from the animal's point of view. Although assessing quality of life in veterinary patients is a central component of practice, structured quality of life assessment is a new, complex, and controversial area in veterinary medicine. When an animal is receiving chemotherapy or experiencing extreme arthritic pain, many practitioners and owners try to discern the pet's quality of life to ensure that the right course is taken. But the authors of a recent study point out that quality of life assessment is important throughout an animal's life. So how can you evaluate an animal's quality of life when it can't provide any feedback itself?
In human medicine, much research has explored quality of life assessment, as has animal welfare science. The authors of an article in the Journal of Small Animal Practice have looked into the history of quality of life assessment in these disciplines as well as what has been used in veterinary practice in an effort to recommend steps all practitioners can use. The authors state that an animal's quality of life is a balance of subjective factors, considering the animal’s point of view, and more objective factors, involving the observer's (e.g. owner's, veterinarian's) point of view. Both factors are critical, and they become, as introduced by the authors, the ideas of mental state approaches and external parameter approaches.
Mental state approaches invoke the assessor's empathy and reflection and attempt to identify an animal's emotions or feelings, such as pain, pleasure, and suffering, as well as an animal's relationships and sense of control. The mental state can be assessed by asking owners how they think their pets might rate their degree of pain or if they would be willing to live the life their pets are currently experiencing.
External parameters are merely indicators of quality of life but can be directly observed from the outside and involve inputs to quality of life, such as the level of care being provided, the animal's environment and social interactions, and even a pet's breed and health. External parameters also involve observable outcomes, such as an animal's biological functioning and social interactions with family members or other animals in a household.
The authors advise open-ended questions to help evaluate an animal's quality of life. Asking how Fluffy is doing, in general, may result in responses that can help you ask more specific questions. For example, the owner may answer that Fluffy is walking more slowly. You can then question the owner further to determine whether this might be from weakness (a physical parameter) or pain (mental state). Numerical scales can also be useful: You might ask an owner to rate their pet’s quality of life on a 10-point scale, with the range between "could not be worse" and "could not be better," or rate the degree of pain they perceive the pet to be experiencing. You might also ask whether a pet is always having good days, always having bad days, or various degrees in between. The authors also advocate using questionnaires, which can be filled out by people familiar with an animal—the owner, the veterinarian, team members. Each will bring a different perspective. Veterinarians and team members will likely provide the more objective side of the quality of life equation; owners will likely have subjective views that can help determine the animal's mental state.
The authors also suggest ways in which the "Five Freedoms"—standards established by the United Kingdom's Farm Animal Welfare Council in 1993 to describe domesticated animals' needs and the duties of care owed them—can be applied to quality of life assessment in companion animals. The five freedoms are freedom from hunger and thirst; discomfort; pain, injury, and disease; and fear and stress; and include being allowed to express normal behavior. For example, in evaluating the affect of sudden onset blindness on a patient and considering these freedoms, practitioners will be reminded to look beyond the disease and help ensure the animal's needs are met by assessing whether the animal's access to food and water is problematic, whether the blindness causes fear or distress, or whether the animal can behave normally by interacting with other people and pets or exploring during walks.
The authors acknowledge that this is a new field in veterinary medicine and much is yet to be learned. Even in human quality of life assessment, no one method has been accepted as the best. But the authors also suggest that the benefits of just starting to consider quality of life in veterinary patients include screening for concerns that owners hadn't identified; encouraging owners to consider issues such as obesity, parasite prevention, pain relief, exercise, and separation anxiety; monitoring for changes in quality of life over time; and aiding in euthanasia decisions. Assessing your patients' quality of life may also increase your clients' involvement and satisfaction and help clients comply with your treatment recommendations.
Yeates J, Main D. Assessment of companion animal quality of life in veterinary practice and research. J Small Anim Pract 2009;50(6):274-281.
Link to abstract: http://www3.interscience.wiley.com/journal/122419922/abstract