Objective—To describe reporting of key methodological elements associated with type II error in published reports of small animal randomized controlled trials (RCTs) and to determine the statistical power in a subset of RCTs with negative results.
Design—Descriptive literature survey.
Sample—Reports of parallel-group clinical RCTs published in 11 English-language veterinary journals from 2005 to 2012.
Procedures—Predefined criteria were used to identify trial primary outcomes and classify results as negative or positive. Details of sample size determination and use of confidence intervals in results reporting were recorded. For each 2-group RCT with negative results, the statistical power to detect 25% and 50% relative differences in outcome was calculated.
Results—Of 238 RCTs, 42 (18%) stated a primary outcome, 52 (22%) reported a sample size calculation, and 18 (9%) included a confidence interval around the observed treatment effect. Reports of only 2 (0.8%) RCTs included all 3 elements. Among 103 two-group RCTs with negative results, only 14 (14%) and 40 (39%) were sufficiently powered (β < 0.20) to detect 25% and 50% relative differences in outcome between treatments, respectively.
Conclusions and Clinical Relevance—The present survey found that small animal RCTs with negative results were often underpowered to detect moderate-to-large effect sizes between study groups. Information needed for critical appraisal was missing from most reports. The potential for clinicians to base treatment decisions on inappropriate interpretations of RCTs was worrisome. Design and reporting of small animal RCTs must be improved.
OBJECTIVE To evaluate methods used to ascertain, define, and report adverse events (AEs) in companion animal clinical trials involving cancer treatment.
DESIGN Systematic review.
SAMPLE English-language articles describing prospective clinical trials involving dogs and cats with naturally occurring cancer published in peer-reviewed journals between 2008 and 2014.
PROCEDURES Reports were identified via MEDLINE and CAB database searches combined with a hand-searching strategy. General article characteristics were abstracted and summarized. Data for AE reporting were collected with a 14-item checklist adapted from the 2004 CONSORT extension for reporting harms. Study characteristics associated with the AE reporting checklist score were identified by means of linear regression analysis.
RESULTS 168 articles with data for 6,132 animals were included. Standardized terminology was significantly more likely to be used to describe AEs for trials that included chemotherapy (92/115 [80.0%]) than for trials that did not (16/53 [30.2%]). Median AE reporting checklist score was 5 out of 14 (range, 0 to 12). Poorly reported items included methods and time frame of AE ascertainment, AE data analysis, and reasons for treatment discontinuation and death. Trials with industry funding, a single-arm design, and treatment with chemotherapy were associated with a significantly higher quality of AE reporting.
CONCLUSIONS AND CLINICAL RELEVANCE Reporting of adverse events in veterinary clinical trials evaluating cancer treatment was selective and heterogeneous. Harms associated with cancer treatments could be underestimated because of suboptimal collection and reporting of AE data. Findings supported the adoption of a higher standard for AE surveillance and reporting in veterinary patients.
A thoughtful, clearly defined research question should be the foundation of any clinical trial or research study. The research question helps determine key study methods, and defining a specific research question helps avoid problems with inadequate sample size, inappropriate design, or multiple statistical comparisons. Rationales and strategies for formulating research questions and using them to define study protocols are discussed, with a focus on application in clinical trials.
OBJECTIVE To describe development and initial psychometric testing of the Canine Symptom Assessment Scale (CSAS), a multidimensional owner-reported questionnaire instrument, in a population of dogs with solid tumors enrolled in clinical trials.
DESIGN Questionnaire development and validation study.
ANIMALS 238 client-owned dogs with solid tumors.
PROCEDURES A 14-symptom questionnaire was developed. Symptoms were defined as subjective physical disturbances dogs experienced during the course of daily living as assessed through proxy reports of pet owners. For each symptom, owners reported frequency and severity of the symptom and extent of distress caused by the symptom for the dog and the owner. Questionnaire content, symptom prevalence and dimensionality, internal consistency, and factor structure were examined. Construct and criterion validity were examined via comparison with the Canine Brief Pain Inventory (CBPI).
RESULTS Symptom prevalence was high, with pain and lack of energy reported in most dogs. Severity, versus frequency, was most highly correlated with both dog and owner distress. Two symptoms were removed from consideration because of poor performance. Analysis of the remaining 12 symptoms revealed that they could be grouped into 3 factors: malaise, anxiety, and digestive upset. The CSAS factor and total scores demonstrated predictable relationships with quality of life and pain scores as measured by the CBPI, including a significant association between increasing symptom burden and decreasing quality of life. The Cronbach α for the CSAS was 0.77.
CONCLUSIONS AND CLINICAL RELEVANCE The 12-item CSAS was a psychometrically sound owner-reported instrument for assessment of symptom frequency and characteristics in client-owned dogs with solid tumors. Potential applications include clinical research and practice settings.
Objective—To review blinding terminology used in published reports of veterinary clinical randomized controlled trials (RCTs) and to determine how practicing veterinarians interpret blinding terminology.
Design—Retrospective literature review and prospective veterinarian survey.
Sample—195 parallel-group clinical RCTs published from June 2004 to June 2010 in 11 peer-reviewed journals; 21 practicing veterinarians at a university-based small animal teaching hospital.
Procedures—Journals were hand searched to identify eligible reports. Details concerning trial methodology were recorded. Veterinarians provided information regarding position, experience, and personal interpretation of blinding terminology via an anonymous questionnaire.
Results—Blinding was reported or inferred in 131 reports of RCTs, yet complete descriptions of who was blinded were present in only 42 (32.1%) reports. Studies for which blinding was reported with the terms single or double blinded were less likely to contain clear descriptions of the role of blinded study personnel, compared with studies reported as blinded or in which blinding was inferred through trial methodology. Veterinarians did not agree on how to interpret the terms single, double, and triple blinded when reading the report of an RCT.
Conclusions and Clinical Relevance—Blinding was commonly used as a means of reducing bias associated with collection and interpretation of data in reports of veterinary RCTs. However, most reports of blinding methodology were incomplete and there was no consistency in how blinding terminology was used by authors or interpreted by veterinarians. Ambiguous reporting hinders the ability of practitioners to assess the validity of trial results and make informed decisions about applying study findings to their patient populations.
OBJECTIVE To compare outcomes for laparoscopic ovariectomy (LapOVE) and laparoscopic-assisted ovariohysterectomy (LapOVH) in dogs.
DESIGN Retrospective case series.
ANIMALS 278 female dogs.
PROCEDURES Medical records of female dogs that underwent laparoscopic sterilization between 2003 and 2013 were reviewed. History, signalment, results of physical examination, results of preoperative diagnostic testing, details of the surgical procedure, durations of anesthesia and surgery, intraoperative and immediate postoperative (ie, during hospitalization) complications, and short- (≤ 14 days after surgery) and long-term (> 14 days after surgery) outcomes were recorded. Data for patients undergoing LapOVE versus LapOVH were compared.
RESULTS Intraoperative and immediate postoperative complications were infrequent, and incidence did not differ between groups. Duration of surgery for LapOVE was significantly less than that for LapOVH; however, potential confounders were not assessed. Surgical site infection was identified in 3 of 224 (1.3%) dogs. At the time of long-term follow-up, postoperative urinary incontinence was reported in 7 of 125 (5.6%) dogs that underwent LapOVE and 12 of 82 (14.6%) dogs that underwent LapOVH. None of the dogs had reportedly developed estrus or pyometra by the time of final follow-up. Overall, 205 of 207 (99%) owners were satisfied with the surgery, and 196 of 207 (95%) would consider laparoscopic sterilization for their dogs in the future.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that short- and long-term outcomes were similar for female dogs undergoing sterilization by means of LapOVE or LapOVH; however, surgery time may have been shorter for dogs that underwent LapOVE. Most owners were satisfied with the outcome of laparoscopic sterilization.
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.
To compare a ventral and a left lateral endoscopic approach to coelioscopy in bearded dragons (Pogona vitticeps).
18 adult bearded dragons.
In a randomized crossover design involving 2 surgical approaches, anesthetized bearded dragons first underwent coelioscopy with a ventral approach (left lateral of midline next to the umbilicus; animal positioned in dorsal recumbency) or left lateral approach (intercostal; animal positioned in right lateral recumbency) and then with the alternate approach. A 2.7-mm × 18-cm, 30° oblique telescope with a 4.8-mm operating sheath and CO2 insufflation at 2 to 5 mm Hg were used. Ease of entry into the coelom and ease of visual examination of visceral structures were scored.
Both approaches were straightforward, with the left lateral approach requiring significantly more time than the ventral approach. Scores for ease of visual examination for the heart, lungs, liver, stomach, intestines, pancreas, gallbladder, left kidney, gonads, and fat body were good to excellent. Visual examination of the spleen and adrenal glands was difficult in most animals via either approach. The left kidney, testis, and vas deferens were easier to see with the left lateral approach, whereas the pancreas in females and gallbladder in both sexes were easier to see with the ventral approach. All bearded dragons recovered without complications from the procedures, except for one with nephritis, renal gout, and hepatic necrosis.
CONCLUSIONS AND CLINICAL RELEVANCE
Both coelioscopy approaches could be safely and effectively used in bearded dragons. Choice of approach should be based on the coelomic structures requiring evaluation.
OBJECTIVE To describe the operative technique, complications, and conversion rates for laparoscopic liver biopsy (LLB) in dogs and evaluate short-term clinical outcome for dogs that underwent the procedure.
DESIGN Retrospective case series.
ANIMALS 106 client-owned dogs.
PROCEDURES Medical records were reviewed to identify dogs that underwent an LLB with a single-port or multiport technique at either of 2 veterinary teaching hospitals from August 2003 to September 2013. Demographic and laboratory data, preoperative administration of fresh frozen plasma, procedural and diagnostic information, intraoperative complications, and survival to discharge were recorded. The LLB specimens were obtained with 5-mm laparoscopic biopsy cup forceps and a grasp-and-twist technique.
RESULTS Prior to surgery, 25 of 94 (27%) dogs had coagulopathy (prothrombin time or partial thromboplastin time greater than the facility reference ranges, regardless of platelet count). Twenty-one dogs were thrombocytopenic, 14 had ascites, and 14 received fresh frozen plasma transfusion before surgery. In all cases, biopsy samples collected were of sufficient size and quality for histopathologic evaluation. Two dogs required conversion to an open laparotomy because of splenic laceration during initial port placement. One hundred one of 106 dogs survived to discharge; 5 were euthanized during hospitalization owing to progression of liver disease and poor prognosis.
CONCLUSIONS AND CLINICAL RELEVANCE Single-port and multiport LLB were found to be effective, minimally invasive diagnostic techniques with a low rate of complications. Results suggested LLB can be safely used in dogs with underlying coagulopathies and advanced liver disease.
To evaluate the use of transrectal ultrasonography (TRUS) for the assessment of prostatic tumors in dogs and to compare results for TRUS with results for other imaging modalities.
10 client-owned male dogs.
Client-owned dogs identified with prostatic carcinoma were enrolled. Fluoroscopy, transabdominal ultrasonography (TAUS), TRUS, and MRI were performed on all dogs. Tumor measurements, urethral penetration (identification of abnormal tissue within the urethral lumen), and tumor extension into the urinary tract were recorded for all imaging modalities. Agreement between results for MRI (considered the criterion-referenced standard) and results for other modalities were compared.
Median body weight of the 10 dogs was 26.3 kg (range, 9.4 to 49.5 kg). No complications were encountered during or after TRUS. Significant moderate to good agreements (intraclass correlation coefficients, 0.60 to 0.86) among TAUS, TRUS, fluoroscopy, and MRI were identified for tumor length and height. Assessments of urethral penetration and tumor extension into the bladder with TRUS did not differ significantly from those made with MRI and were superior in terms of absolute agreement with MRI when compared with those for TAUS.
CONCLUSIONS AND CLINICAL RELEVANCE
TRUS was successfully and safely used to evaluate prostatic carcinoma in dogs. There was moderate to good agreement with MRI results for tumor height and length measurements, and TRUS was found to be superior to TAUS for some assessments. Transrectal ultrasonography can be considered an adjunctive imaging modality for the performance of prostatic interventional procedures or assessment of response to treatment.