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Abstract

Objective—To determine the sources and handlingof losses to follow-up (LTF) in parallel-group randomized clinical trials (RCTs).

Sample Population—63 parallel-group RCTs of > 24 hours' duration published from January 2000 through December 2005.

Procedures—Journals were hand searched for eligible reports. Details concerning the presence, cause, and amount of LTF; statistical handlingof data missingbecause of LTF; type of analyses performed; number of animals randomly allocated and analyzed; and the acknowledgement of the potential impact of LTF were recorded.

Results—In 81% (51/63) of trials, LTF were reported. In 80% (41/51) of those studies, losses in the analysis were ignored, and in only 18% (9/51) was the potential impact of LTF on study results acknowledged. Of the 47 studies in which sources of LTF were reported, 72% had loss of subjects because of investigator withdrawals, 30% because of deaths, and 26% because of owner withdrawals. Median loss of subjects for those studies was 12% because of investigator withdrawal (range, 2% to 52%), 8% because of death (1% to 28%), and 4% because of owner withdrawal (2% to 33%).

Conclusions and Clinical Relevance—Most RCTs had LTF, most of which were attributable to investigators removing randomly allocated animals from the study. In most studies, data from animal LTF were ignored and, therefore, only a subgroup of randomly allocated subjects was included in the data analysis. Most reports did not address the potential for a postrandomization selection bias associated with ignoring LTF and did not acknowledge the potential impact of the missingdata on their results.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine how selection bias (allocation bias) was controlled in published clinical trials.

Design—Retrospective study.

Sample Population—97 parallel-group controlled clinical trials published from January 2000 through December 2005 in 12 peer-reviewed journals.

Procedures—Journals were hand searched to identify eligible reports. Details concerning allocation of animals to study groups, baseline characteristics of the groups, and the number of animals allocated to each group were recorded.

Results—Randomization was the stated method of allocating animals to groups in 87% of the reports, yet in only 11% of reports were both randomization of the group allocation process and concealment of the allocation sequence described. Studies reported as randomized were more likely to report baseline characteristics of the study groups for comparison than studies that did not report randomization (88% vs 54%). Studies in which baseline group characteristics were reported had more subjects allocated to each study group (median, 16) than those that did not (median, 11).

Conclusions and Clinical Relevance—Randomization was reported as the method of allocating study animals to groups in most publications, indicating that the potential power of randomization in controlling selection bias is appreciated by clinical investigators seeking to determine the efficacy of an intervention. However, in most reports, little corroborating information was included to support the claim. The absence of this information makes it difficult for practitioners to critically review the impact of bias on study results and make informed decisions regarding patients.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To investigate whether an accelerometer-based activity monitor could be used in pet dogs to differentiate among and delineate the amount of time spent in activities of differing intensity.

Animals—104 dogs.

Procedures—For the first phase of the study, each dog (n = 104) wore an accelerometer-based activity monitor and was led through a series of standard activities (recumbency [sedentary], walking, and trotting). Receiver operating characteristic curves were generated to determine the optimal activity counts for predicting whether a dog was sedentary, walking, or trotting. For the second phase of the study, dogs (n = 99) wore an activity monitor on their collars continuously for 14 days at home; intensity of activity for each dog was classified by use of cut points determined on the basis of results obtained during the first phase of the study.

Results—Analysis of receiver operating characteristic curves indicated that there was 100% specificity and 100% sensitivity in distinguishing sedentary activity from walking activity and 92% specificity and 92% sensitivity in distinguishing trotting activity from walking activity. Analysis of data collected during the 14-day period at home indicated that dogs were sedentary most of the time (median, 87%; range, 65% to 95%).

Conclusions and Clinical Relevance—Counts recorded by an accelerometer-based activity monitor could be used to discriminate effectively among standardized activities in pet dogs. There is potential for use of the method to improve the ability of clinicians and researchers to accurately estimate a pet dog's daily energy requirement.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the optimal method for use of the Canine Brief Pain Inventory (CBPI) to quantitate responses of dogs with osteoarthritis to treatment with carprofen or placebo.

Animals—150 dogs with osteoarthritis.

Procedures—Data were analyzed from 2 studies with identical protocols in which owner-completed CBPIs were used. Treatment for each dog was classified as a success or failure by comparing the pain severity score (PSS) and pain interference score (PIS) on day 0 (baseline) with those on day 14. Treatment success or failure was defined on the basis of various combinations of reduction in the 2 scores when inclusion criteria were set as a PSS and PIS ≥ 1, 2, or 3 at baseline. Statistical analyses were performed to select the definition of treatment success that had the greatest statistical power to detect differences between carprofen and placebo treatments.

Results—Defining treatment success as a reduction of ≥ 1 in PSS and ≥ 2 in PIS in each dog had consistently robust power. Power was 62.8% in the population that included only dogs with baseline scores ≥ 2 and 64.7% in the population that included only dogs with baseline scores ≥ 3.

Conclusions and Clinical Relevance—The CBPI had robust statistical power to evaluate the treatment effect of carprofen in dogs with osteoarthritis when protocol success criteria were predefined as a reduction ≥ 1 in PIS and ≥ 2 in PSS. Results indicated the CBPI can be used as an outcome measure in clinical trials to evaluate new pain treatments when it is desirable to evaluate success in individual dogs rather than overall mean or median scores in a test population.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effect of signalment and body conformation on activity monitoring in companion dogs.

Animals—104 companion dogs.

Procedures—While wearing an activity monitor, each dog was led through a series of standard activities: lying down, walking laps, trotting laps, and trotting up and down stairs. Linear regression analysis was used to determine which signalment and body conformation factors were associated with activity counts.

Results—There was no significant effect of signalment or body conformation on activity counts when dogs were lying down, walking laps, and trotting laps. However, when dogs were trotting up and down stairs, there was a significant effect of age and body weight such that, for every 1-kg increase in body weight, there was a 1.7% (95% confidence interval, 1.1% to 2.4%) decrease in activity counts and for every 1-year increase in age, there was a 4.2% (95% confidence interval, 1.4% to 6.9%) decrease in activity counts.

Conclusions and Clinical Relevance—When activity was well controlled, there was no significant effect of signalment or body conformation on activity counts recorded by the activity monitor. However, when activity was less controlled, older dogs and larger dogs had lower activity counts than younger and smaller dogs. The wide range in body conformation (eg, limb or body length) among dogs did not appear to significantly impact the activity counts recorded by the monitor, but age and body weight did and must be considered in analysis of data collected from the monitors.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine by use of an accelerometer the sampling interval that has the least variable total activity counts from one week to the next in companion (ie, nonlaboratory) dogs.

Animals—80 dogs.

Procedures—Dogs wore an accelerometer continuously for 2 weeks. Between-dog and within-dog day-to-day variability in total activity counts were evaluated. The changes in counts between week 1 and week 2 were compared for weekdays, weekends, and full weeks.

Results—Significant between-dog variability in total activity counts was detected. Within dogs, there was significant day-to-day variability, with highest counts recorded on weekends. In comparison of data from the first week with data from the second week, the greatest differences were in weekend counts (median difference, 21%; range, 0% to 154%) and the smallest differences were in full 7-day counts (median difference, 10%; range, 0% to 74%). Comparison of weekday counts revealed a median change of 12% (range, 0% to 104%).

Conclusions and Clinical Relevance—Significant between-dog variability in total daily activity counts was detected. Within dogs, a full 7-day comparison of total activity counts from one week to the next provided the least variable estimate of the dogs' activity. For dogs in their home environment, the activity monitor may be most useful in following changes in activity over time. For dogs that have no change in routine according to the owner's report, the least variable estimates of activity can be collected by comparing activity in 7-day intervals.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether the Canine Brief Pain Inventory (CBPI) can detect changes in dogs with osteoarthritis treated with an NSAID or a placebo.

Design—Double-blind, randomized, placebo-controlled clinical trial.

Animals—70 dogs with osteoarthritis.

Procedures—Owners completed the CBPI on day 0. Dogs received carprofen or a placebo on days 1 through 14. Owners completed the CBPI again on day 14. Pain severity and pain interference scores from the CBPI were calculated, and the change from day 0 to day 14 was assessed within each group and between groups.

Results—No significant differences were detected in median scores for pain severity (3.50 and 3.25 on days 0 and 14, respectively) and pain interference (3.92 and 3.25 on days 0 and 14, respectively) in dogs receiving the placebo. Dogs receiving carprofen had significant changes in median scores for pain severity (4.25 to 2.25 on days 0 and 14, respectively) and pain interference (4.33 to 2.67 on days 0 and 14, respectively). There was a significantly greater improvement in pain severity and pain interference scores in dogs treated with carprofen, compared with improvement in scores for dogs receiving the placebo.

Conclusions and Clinical Relevance—The CBPI was able to detect improvements in pain scores in dogs with osteoarthritis treated with an NSAID or a placebo. These results, in combination with previous reliability and validity testing, support the use of the CBPI to obtain quantifiable assessments from owners regarding the severity and impact of chronic pain and treatment for dogs with osteoarthritis.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate risk factors for gastric dilatation-volvulus (GDV) in a large number of privately owned dogs across a wide geographic area.

Design—Internet-based, cross-sectional study.

Animals—2,551 privately owned dogs.

Procedures—A questionnaire addressed dog-specific, management, environmental, and personality-associated risk factors for GDV in dogs. Respondents were recruited through the posting of the electronic link to the questionnaire on websites for dog owners; the information was also disseminated at meetings of dog owners and via newsletters, e-mail lists for dog owners and breeders, owner-oriented dog publications, and e-mails forwarded by participants. Descriptive statistics and logistic regression analysis were performed.

Results—Factors significantly associated with an increased risk of GDV were being fed dry kibble, anxiety, residence in the United Kingdom, being born in the 1990s, being a family pet, and spending at least 5 hours a day with the owner. Factors associated with a decreased risk of GDV were playing with other dogs and running the fence after meals, fish and egg dietary supplements, and spending equal time indoors and outdoors. A significant interaction between sex and neuter status was observed, with sexually intact females having the highest risk for GDV.

Conclusions and Clinical Relevance—In dogs with a high risk of GDV, regular moderate daily and postprandial activity appeared to be beneficial. Feeding only commercial dry dog food may not be the best choice for dogs at risk; however, supplements with fish or eggs may reduced this risk. The effect of neuter status on GDV risk requires further characterization.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To describe development and initial psychometric testing of an owner-reported questionnaire designed to standardize measurement of general quality of life (QOL) in dogs with cancer.

DESIGN Key-informant interviews, questionnaire development, and field trial.

SAMPLE Owners of 25 dogs with cancer for item development and pretesting and owners of 90 dogs with cancer for reliability and validity testing.

PROCEDURES Standard methods for development and testing of questionnaire instruments intended to measure subjective states were used. Items were generated, selected, scaled, and pretested for content, meaning, and readability. Response items were evaluated with exploratory factor analysis and by assessing internal consistency (Cronbach α) and convergence with global QOL as determined with a visual analog scale. Preliminary tests of stability and responsiveness were performed.

RESULTS The final questionnaire—which was named the Canine Owner-Reported Quality of Life (CORQ) questionnaire—contained 17 items related to observable behaviors commonly used by owners to evaluate QOL in their dogs. Several items pertaining to physical symptoms performed poorly and were omitted. The 17 items were assigned to 4 factors—vitality, companionship, pain, and mobility—on the basis of the items they contained. The CORQ questionnaire and its factors had high internal consistency (Cronbach α = 0.68 to 0.90) and moderate to strong correlations (r = 0.49 to 0.71) with global QOL as measured on a visual analog scale. Preliminary testing indicated good test-retest reliability and responsiveness to improvements in overall QOL.

CONCLUSIONS AND CLINICAL RELEVANCE The CORQ questionnaire was a valid, reliable owner-reported questionnaire that measured general QOL in dogs with cancer and showed promise as a clinical trial outcome measure for quantifying changes in individual dog QOL occurring in response to cancer treatment and progression.

Full access
in Journal of the American Veterinary Medical Association