Page 26 - Small Animal Clinical Nutrition 5th Edition

26 Small Animal Clinical Nutrition

• Are there differences in the nutrient contents of the food Alternatively, treatment decisions can be based on critical
(or supplements) that may alter the expected treatment
VetBooks.ir • Is the food (or supplement) readily available and economi- analysis of formal, prospective randomized clinical trials
response?
designed to determine if differences exist in clinically relevant
outcomes between treatments. In clinical trials, researchers
cally feasible? apply a treatment or intervention and observe the effect of
• Is the feeding plan intervention feasible in the owner’s treatment on outcome.The value of interventional compared to
setting? observational studies is the ability to determine causality.
• What are the patient’s likely benefits and risks from the The purpose of clinical research is to draw inferences about
various nutritional management options? what really happened in the study patients and to apply those
• How will the owner’s values and patient’s preferences influ- inferences to the universe of all patients with the same problem.
ence the decision about nutritional management? Errors are inherent in all clinical research studies.The key issue
• Does the patient have other health conditions that substan- is whether the errors change the conclusions of a study signifi-
tially alter the potential benefits and risks of nutritional cantly. The challenge is to design and complete a study that
management? adequately controls for random and systematic errors.
Randomly assigning patients to treatment can eliminate the
influence of confounding variables. Masking the veterinarian
EVIDENCE-BASED TREATMENT and pet owner to treatment can reduce the possibility that clin-
DECISIONS: A FRAMEWORK FOR ical assessments are biased. Randomized, controlled masked
CLINICAL PRACTICE clinical trials are considered the gold standard of clinical
research because they provide the best way to reduce bias. Bias
EBM involves making clinical decisions by carefully identify- is anything that produces results or conclusions that differ from
ing, evaluating and applying the most relevant information. In the truth. Sources of bias can be found in the design, imple-
EBM, the first step is to identify and define the medical prob- mentation and analysis of the study.
lem to learn what additional information is required. After the In general, clinical trials are expensive, time consuming and
need for additional information is identified, it must be difficult to conduct. Consequently, well-designed, well-exe-
retrieved and evaluated to ensure validity. After the information cuted clinical trials are unavailable to guide every treatment
is judged valid, it is next necessary to apply it to the care of your decision. Nonetheless, a systematic approach to evaluating
patient. This brief section will focus on how to evaluate infor- support for each treatment option is valuable to the clinician.
mation about treatment after it has been retrieved and conclude The critical evaluation of a clinical trial depends on more than
with a few general comments about applying treatments to checking for appropriate randomization and the presence of a
individual patients. control group. The following series of questions can guide the
The first step in making good treatment decisions is to clinician through a systematic assessment of the validity of a
decide whether the patient requires treatment or not and to clinical trial.
identify the specific goals of treatment. Potential treatment
goals include eliminating or decreasing current clinical signs, Was Assignment to Treatment Truly
preventing recurrence of disease, slowing progression of disease Randomized?
and curing the disease. After the treatment goals have been Did every patient enrolled in the study have an equal and
identified and treatment has been initiated it is important to known probability of receiving the treatment(s) compared?
periodically assess progress toward these goals and to make Proper randomization applies a previously established
changes as appropriate. method for assigning patients to a treatment group using a set
After the decision to treat has been made and the treatment of computer-generated random numbers. The random
goals identified, the next step is to decide on the specific treat- assignment of patients to treatment groups is critical for
ment modality or modalities (pharmacologic agents, surgery establishing the basis for statistical testing of the differences
and nutrition) that will achieve the treatment goals. in the clinical outcomes observed between groups. In blocked
Experienced clinicians make treatment decisions based on their randomization, age, sex and other baseline characteristics that
own uncontrolled clinical experience. Clinicians judge the effi- may influence clinical outcomes are distributed equally
cacy of a treatment by comparing current clinical impressions between treatment groups and do not confound interpreta-
with clinical impressions before the new treatment was avail- tion of results. When block randomization is done properly
able. Unfortunately, this approach can lead to erroneous con- any differences in baseline characteristics between the groups
clusions. Part of human nature is to remember our successes are due to chance and addressed by the statistical tests. Proper
and either forget our treatment failures or attribute them to random assignment guarantees that no one can influence
other factors (e.g., poor owner compliance). Another risk when assignment to treatment. This prevents the investigator from
judging the efficacy of a treatment based on clinical impressions knowingly or unknowingly assigning a particular patient to a
is that neither the clinician nor the pet owner is masked to specific treatment because the patient seems particularly suit-
treatment so there is increased potential for bias in subjective ed to receive the active or control treatment, thereby eliminat-
assessments (placebo effect). ing an important potential source of bias.