FC‐24 Risk factors for atopic dermatitis in a Swedish population of insured dogs

Studies into the epidemiology of canine atopic dermatitis (CAD) are in great demand. Estimates of the prevalence and incidence of CAD are commonly based on hospital studies where no reference population is defined. Such studies tend to overestimate the disease frequency due to referral bias and a higher proportion of complicated cases at secondary care centres than in the general population. The aim of this paper was to present better estimates of the incidence of CAD. The Swedish dog population offers unique opportunities to study the epidemiology of CAD due to several characteristics: a large proportion of dogs are purebred, fleas and flea allergies are rare, and a secondary database of disease records is available through an insurance company that covers approximately 30% of all Swedish dogs. By accessing insurance‐claims records for the years 1995–2000, the true incidence rate of CAD was estimated as 10 cases per 10,000 dog years at risk. Univariate analysis showed that the incidence was the same across genders. Additionally, large differences in the risk of being diagnosed with CAD existed among breeds. In this study, breeds with the highest risk were the bull terrier (88 cases/10,000 dog years at risk), Staffordshire bull terrier (58/10,000), West Highland white terrier (51/10,000), Welsh terrier (50/10,000) and boxer (50/10,000). Decreased risk was observed among sighthounds; no cases were recorded among the Borzoi, Saluki and Whippet breeds. A proportional hazards (survival) model was developed in order to take sex, breed, age and geographical region into account in a multivariate analysis. Funding: Swedish University of Agricultural Sciences, The Foundation for Research.     

The spatial distribution of atopic dermatitis cases in a population of insured Swedish dogs

Canine atopic dermatitis (CAD) is manifested by pruritus and inflammation of the skin, and most affected dogs have specific IgE against environmental allergens. Our aim was to evaluate whether in Sweden the incidence of CAD varies spatially, and to investigate possible environmental causes of such variation in a longitudinal study of CAD incidence among insured Swedish dogs. The dataset consisted of >220,000 individuals which had been covered by an insurance plan between January 1, 1995 and December 31, 2002. Out of these, 1235 CAD cases were identified and matched to postal-code areas based upon the address of the owner. Environmental risk factors we considered included averages of long-term annual rainfall, and of January and July temperatures. Initial visualization of the incidence rate of CAD (cases/dog-years at risk) expressed as empirical Bayes smoothed spatial rates indicated geographic variation. Moran's I, adjusted for population at risk, revealed significant global clustering. Both the spatial scan statistic and a local indicator of spatial autocorrelation revealed a higher incidence of CAD in the major cities. In a Poisson-regression model (with a spatial covariance structure), the incidence of CAD increased with increasing human population density, increasing average annual rainfall, living in the southern half of Sweden, and having a veterinary dermatologist in the county.     

Incidence and breed predilection for dystocia and risk factors for cesarean section in a Swedish population of insured dogs

OBJECTIVES: To estimate the incidence and breed predilection for canine dystocia using data from insurance claims. The risk factors for cesarean section (CS) were assessed for bitches with dystocia. STUDY DESIGN: Retrospective, longitudinal study. SAMPLE POPULATION: Insurance claims records (1995-2002) from a Swedish animal insurance database (Agria), including approximately 200,000 bitches. METHODS: The overall incidence rate of dystocia in insured bitches was calculated by dividing the number of reimbursed dystocia claims with the number of dog years at risk. Subsequently, incidence rates were stratified by breed, region, and habitat. The proportion of bitches with a dystocia claim that had CS were calculated, and risk factors for CS were assessed using a logistic regression model. RESULTS: Between 1995 and 2002, 3894 (2%) of 195,931 Swedish bitches included in the study had a reimbursed insurance claim for dystocia. The overall incidence rate of dystocia was 5.7 cases/ 1000 dog years at risk. Some breeds like the Scottish terrier were at increased risk of dystocia. Among bitches with dystocia, 63.8% were treated by CS. CONCLUSION: Dystocia in the bitch is more common than reported earlier. The risk of developing dystocia varies by breed, and a high percentage (63.8%) of affected bitches undergo CS. Clinical Relevance- Breeders and veterinarians could use this information to better predict which bitches are likely to experience dystocia and/or CS.     

Demographic data of a population of insured Swedish dogs measured in a questionnaire study.

Dogs, in the age range 1-3 years old, were randomly selected from the largest animal insurance database in Sweden for inclusion in the study. The study was performed in 1997, and a total of 680 dog owners were selected for the study. A total of 461 dog owners completed the survey, at an overall response rate of 68%. Data was compared to a recent gallup performed on a sample of all dogs in Sweden. The demographic statistics of the insured dog population were in many aspects similar to the total dog population of Sweden. Typical for both insured dogs and the total population of dogs were a low proportion of neutered dogs, that many dogs were bought at an early age, that many dogs were in contact with a "breeder" when sold, and a similar profile of health status. However, "dog breeders" seemed to have their dogs insured to a higher extent than the general dog owner. It was concluded that as the populations were alike in many respects, it is reasonable to use the insurance database for epidemiological studies on diet and exercise in Swedish dogs.     

Incidence of and breed-related risk factors for gastric dilatation-volvulus in dogs

OBJECTIVE: To compare incidence of and breed-related risk factors for gastric dilatation-volvulus (GDV) among 11 dog breeds (Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner). DESIGN: Prospective cohort study. ANIMALS: 1,914 dogs. PROCEDURE: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog's length and height and depth and width of the thorax and abdomen were measured. Information concerning the dogs' medical history, genetic background, personality, and diet was obtained from owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV based on the number of dog-years at risk was calculated for each breed, and breed-related risk factors were identified. RESULTS AND CLINICAL RELEVANCE: Incidence of GDV for the 7 large (23 to 45 kg [50 to 99 lb]) and 4 giant (> 45 kg [> 99 lb]) breeds was 23 and 26 cases/1,000 dog-years at risk, respectively. Of the 105 dogs that developed GDV, 30 (28.6%) died. Incidence of GDV increased with increasing age. Cumulative incidence of GDV was 5.7% for all breeds. The only breed-specific characteristic significantly associated with a decreased incidence of GDV was an owner-perceived personality trait of happiness.     

Incidence of presenting complaints and diagnoses in insured Australian dogs

Knowledge of the most common presenting complaints and diagnoses in companion animals is valuable in preparing veterinary students and veterinarians to manage the most frequently observed conditions in clinical practice. Pet insurance databases provide access to large sample populations and have been previously used to describe disease incidence in companion animals. The aim of this study was to determine the incidence of presenting complaints and diagnoses in insured Australian dogs through the use of a pet insurance database. Analysis of a de-identified dataset containing pet insurance claims associated with presenting complaints and diagnoses from 488,472 insured Australian dogs insured in the years 2016 and 2017, was performed. Annual incidence rates of presenting complaints and diagnoses were calculated and expressed as, number of events per 1,000 dog years at risk. The presenting complaints with the highest incidence were vomiting (14.21 events per 1,000 dog years at risk in 2016, 15.80 events per 1,000 dog years at risk in 2017) and pruritus (8.79 events per 1,000 dog years at risk in 2016, 10.30 events per 1,000 dog years at risk in 2017). Presenting complaints affecting the gastrointestinal system were the most common (19.20 events per 1,000 dog years at risk in 2016, 20.77 events per 1,000 dog years at risk in 2017). The diagnoses with the highest incidence were otitis externa (34.12 events per 1,000 dog years at risk in 2016, 34.82 events per 1,000 dog years at risk in 2017) and dermatitis (28.05 events per 1,000 dog years at risk in 2016, 29.99 events per 1,000 dog years at risk in 2017). Diagnoses affecting the integument were the most common (216.56 events per 1,000 dog years at risk in 2016, 219.06 events per 1,000 dog years at risk in 2017). The results from this study can aid in the design of relevant veterinary curricula and may be helpful in prioritising research on common clinical conditions.     

Breed incidence of lymphoma in a UK population of insured dogs

Canine lymphoma is one of the commonest forms of spontaneous canine neoplasia. Improved understanding of the genetic and environmental risk factors for canine lymphoma, including breed differences, may have comparative benefits for the study of non‐Hodgkin's lymphoma in humans. In this study, data from a pet insurance company were used to estimate the incidences of canine lymphoma for pedigree breeds in the UK. Out of a total of 130 684 insured dogs, 103 had a diagnosis of lymphoma recorded. A significant breed effect was found with the boxer, bulldog and bull mastiff breeds, all having a high incidence of lymphoma. The small number of lymphoma cases recorded may have limited our ability to detect other breeds with an elevated risk. Incidence of lymphoma was found to increase with age, peaking at 10 years of age.     

Bone tumors in a population of 400 000 insured Swedish dogs up to 10 y of age: incidence and survival

The objectives of this study were to describe the incidence of, survival until, and survival after the diagnosis of canine bone tumors by breed, sex, age, and geographic location of residence. Dogs under 10 y old and insured by a Swedish insurance company between 1995 and 2002 were studied. In total, 764 dogs had claims for bone tumors, and the incidence rate was 5.5 cases per 10 000 dog-years at risk (DYAR). At ages 6, 8, and 10 y, the proportions of dogs with bone tumors were 0.13%, 0.30%, and 0.64%. The top 3 breeds at risk were Irish wolfhound, St. Bernard, and leonberger (incidence rates 99, 78, and 53 cases per 10 000 DYAR, respectively). Median survival time after diagnosis was 56 d in the 419 dogs that survived > or = 1 d. With a Cox regression model controlling for breed and age, females were shown to be at decreased risk of bone tumors, with a hazard ratio of 0.71 (99% confidence interval 0.58 to 0.87).     

A case-control study of risk factors for canine atopic dermatitis among boxer, bullterrier and West Highland white terrier dogs in Sweden

Environmental and dietary risk factors for the development of canine atopic dermatitis (CAD) in the high-risk breeds of boxer, bullterrier and West Highland white terrier were assessed in a case-control study. A logistic regression model was developed to evaluate their relative importance in 58 cases from 12 practices in Sweden and 61 unaffected controls, matched to cases by breed and year of birth. The final model included a random error term for 'examining veterinarian', as dogs from the same practice were not considered independent. No effect of gender, season of birth, environment, vaccination or de-worming practices on the odds of developing CAD was detected. The main finding was that feeding a diet including noncommercial products to the bitch during lactation had a protective effect on the development of CAD in her offspring; the odds of developing CAD were twice as high among offspring from bitches that were not exposed to home-made/noncommercial diets [95% confidence interval (CI) of the odds ratio: 1.2-3.8]. The population attributable fraction for not feeding home-made diets to the lactating bitch was estimated as 0.4 (95% CI: 0.04-0.63). Randomized controlled clinical trials are needed to further support the finding of a potential protective role of diet in CAD development.     

Effect of hyposensitization on atopic dermatitis in dogs

In a double-blind study, 51 dogs with clinically defined atopic dermatitis were injected with either alum-precipitated allergen solutions or a placebo. Comparing the treatment results of both groups on the basis of scores for clinical signs, a significant difference in clinical improvement was established in favor of the allergen-treated dogs (P less than 0.01). The proportional changes of scores for clinical signs in the allergen-treated group ranged between +27.3% and -100% (median, -61.5%) and in the placebo group between +36.4% and -100% (median, 0.0%) with respect to the initial scores. Immediate skin test reactivity disappeared only in the dogs with a good clinical response. Of 27 dogs treated with an allergen solution, 16 (59.3%) had an improvement of 51% or more. In the placebo group, 5 of 24 dogs (20.8%) reacted this way. There was total remission of the clinical signs in 9 and 4 dogs, respectively. In the dogs in which, after 9 months of hyposensitization, any improvement was observed, the chance for final improvement of more than 51% was calculated as 84%. Discriminant analysis revealed that evaluation of the effect of immunotherapy can be restricted to the 9-month follow-up examination.     

Breed risk of pyometra in insured dogs in Sweden

An animal insurance database containing data on over 200,000 dogs was used to study the occurrence of pyometra with respect to breed and age during 1995 and 1996 in Swedish bitches <10 years of age. A total of 1,803 females in 1995 and 1,754 females in 1996 had claims submitted because of pyometra. Thirty breeds with at least 800 bitches insured each year were studied using univariate and multivariate methods. The crude 12-month risk of pyometra for females <10 years of age was 2.0% (95% confidence interval = 1.9-2.1%) in 1995 and 1.9% (1.8-2.0%) in 1996. The occurrence of pyometra differed with age, breed, and geographic location. The risk of developing pyometra was increased (identified using multivariate models) in rough Collies, Rottweilers, Cavalier King Charles Spaniels, Golden Retrievers, Bernese Mountain Dogs, and English Cocker Spaniels compared with baseline (all other breeds, including mixed breed dogs). Breeds with a low risk of developing the disease were Drevers, German Shepherd Dogs, Miniature Dachshunds, Dachshunds (normal size), and Swedish Hounds. Survival rates indicate that on average 23-24% of the bitches in the databases will have experienced pyometra by 10 years of age. In the studied breeds, this proportion ranged between 10 and 54%. Pyometra is a clinically relevant problem in intact bitches, and differences related to breed and age should be taken into account in studies of this disease.     

Clinical use of a ceramide-based moisturizer for treating dogs with atopic dermatitis

In humans, skin barrier dysfunction is thought to be responsible for enhanced penetration of allergens. Similar to conditions seen in humans, canine atopic dermatitis (CAD) is characterized by derangement of corneocytes and disorganization of intercellular lipids in the stratum corenum (SC) with decreased ceramide levels. This study was designed to evaluate the effects of a moisturizer containing ceramide on dogs with CAD. Dogs (n = 20, 3~8 years old) with mild to moderate clinical signs were recruited and applied a moisturizer containing ceramide for 4 weeks. Transepidermal water loss (TEWL), skin hydration, pruritus index for canine atopic dermatitis (PICAD) scores, and canine atopic dermatitis extent and severity index (CADESI) scores of all dogs were evaluated. Skin samples from five dogs were also examined with transmission electron microscopy (TEM) using ruthenium tetroxide. TEWL, PICAD, and CADESI values decreased (p < 0.05) and skin hydration increased dramatically over time (p < 0.05). Electron micrographs showed that the skin barrier of all five dogs was partially restored (p < 0.05). In conclusion, these results demonstrated that moisturizer containing ceramide was effective for treating skin barrier dysfunction and CAD symptoms.     

Incidence of and survival after mammary tumors in a population of over 80,000 insured female dogs in Sweden from 1995 to 2002

The main objective of this study was to describe the incidence of mammary tumors (MTs) and the survival after MTs, in female dogs between 3 and 10 years of age (insured for veterinary care and with life insurance in a Swedish animal-insurance company) from 1995 to 2002. Measures of incidence are presented crudely, by breed and across age categories and birth cohorts (1991-1998). The survivals until MT diagnosis and after a MT diagnosis were computed. The overall incidence for any MT claim was 111 dogs per 10,000 dog-years at risk (DYAR). The overall MT rate in the 1992 and 1993 birth cohorts was 154 dogs per 10,000 DYAR. The incidence for any MT claim increased with age and varied by breed, from 319 dogs per 10,000 DYAR in the English springer spaniel to 5 dogs per 10,000 DYAR in the rough-haired collie. At the ages 6, 8 and 10 years, 1%, 6% and 13% respectively, of all females had at least one MT claim. The MT mortality was 6 deaths per 10,000 DYAR and increased with age. The overall-case fatality was 6%.     

Interventions for atopic dermatitis in dogs: a systematic review of randomized controlled trials

The objective of this systematic review, which was performed following the guidelines of the Cochrane collaboration, was to assess the effects of interventions for treatment of atopic dermatitis (AD) in dogs. Citations identified from three databases (MEDLINE, Thomson's Science Citation Index Expanded and CAB Abstracts) and trials published by December 2007 were selected. Proceedings books from the major veterinary dermatology international congresses were hand searched for relevant citations. The authors selected randomized controlled trials (RCTs), published from January 1980 to December 2007, which reported the efficacy of topical or systemic interventions for treatment or prevention of canine AD. Studies had to report assessments of either pruritus or skin lesions, or both. Studies were selected and data extracted by two reviewers, with discrepancies resolved by a third arbitrator. Missing data were requested from study authors of recently published trials. Pooling of results and meta-analyses were performed for studies reporting similar interventions and outcome measures. A total of 49 RCTs were selected, which had enrolled 2126 dogs. This review found some evidence of efficacy of topical tacrolimus (3 RCTs), topical triamcinolone (1), oral glucocorticoids (5), oral ciclosporin (6), subcutaneous recombinant γ-interferon (1) and subcutaneous allergen-specific immunotherapy (3) to decrease pruritus and/or skin lesions of AD in dogs. One high-quality RCT showed that an oral essential fatty acid supplement could reduce prednisolone consumption by approximately half. Additional RCTs of high design quality must be performed to remedy previous flaws and to test interventions for prevention of flares of this disease.     

Pilot investigation of a model for canine atopic dermatitis: environmental house dust mite challenge of high-IgE-producing beagles, mite hypersensitive dogs with atopic dermatitis and normal dogs

Although canine atopic dermatitis (cAD) is common, few models are available. The aim of this study was to evaluate high-IgE beagles epicutaneously sensitized to house dust mite (HDM) as a possible model for cAD. Six high-IgE beagles were environmentally challenged with HDM using various doses and protocols. Similar challenge protocols were used in positive and negative control dogs: three dogs with naturally occurring cAD and positive intradermal skin test (IDT) to HDM and three normal dogs without history of skin disease and negative IDT to HDM. All high-IgE beagles and all atopic dogs developed severe cutaneous lesions and pruritus after challenge. Lesions were erythematous papules and macules in contact areas such as face, ears, ventral abdomen, groin, axillae and feet. They were first visible after 6 h and increased in severity over time. No normal dog developed pruritus or lesions. Biopsies of representative lesions in the high-IgE beagles were taken for histopathology and immunohistochemistry. There was superficial perivascular dermatitis with mononuclear infiltrates and spongiosis. Lymphocytes and eosinophils accumulated in small epidermal micro-abscesses with hyperplasia of epidermal IgE-bearing dendritic cells. These findings suggest that this colony of high-IgE beagles develops a dermatitis that clinically, histopathologically and immunologically resembles the naturally occurring canine disease. It is also concluded that this modality of challenge is not irritating to normal dogs but induces flare-ups in hypersensitive atopic dogs.     

Results of allergen-specific immunotherapy in 117 dogs with atopic dermatitis

The success of the treatment of 117 dogs with atopic dermatitis with allergen-specific immunotherapy for up to 48 months was assessed. An excellent response (remission with exclusive immunotherapy) was recorded in 18 of the dogs, a good response (more than 50 per cent reduction in medication and improvement of clinical signs) was recorded in 57, a moderate response was recorded in 24 and a poor response in 18. The mould antigens in the allergen extract were stored in a separate vial before administration and the success rate of the immunotherapy including mould antigens was much higher than in an earlier study in which mould and pollen antigens had been stored in one vial. The success rate was not affected significantly by the age of the dogs when the disease developed, or by their age or the period for which they had shown clinical signs when the treatment began; it was also unaffected by whether pollens, moulds or dust mites were used as antigens, or by whether the offending allergens had been identified by intradermal testing or by serum testing for allergen-specific immunoglobulin E.     

Heart disease as a cause of death in insured Swedish dogs younger than 10 years of age

BACKGROUND: Population-based information on disease occurrence is paramount in clinical decision making and in designing preventative measures, but such information is scarce. HYPOTHESIS: The risk of cardiac death is higher in certain breeds and mortality varies by age and sex. DOGS: Dogs that were life insured by an animal insurance company between 1995 and 2002. METHODS: The mortality pattern for heart disease in insured dogs up to 10 years of age was studied. The influences of sex, age, breed, month, and geographic location were investigated by means of incidence rates, proportions, and survival proportions. Cox proportional hazards regression was used to model time to heart disease. RESULTS: 405,376 dogs contributed to a denominator of 1,431,933 dog-years at risk (DYAR) and 3,049 dogs had been assigned a cardiac-related diagnosis as cause of death. The cardiac-related mortality for dogs <10 years of age, was 21.3 deaths per 10,000 DYAR. This mortality in males and females was 27.3 deaths and 15.4 deaths per 10,000 DYAR, respectively. Twelve of 54 breeds had a point estimate above the overall rate. The 3 breeds with the highest point estimates were: Irish Wolfhounds, Cavalier King Charles Spaniels, and Great Danes (rates of 356, 247, and 179 deaths per 10,000 DYAR, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE: Breed, age, and sex affect cardiac mortality in certain breeds of dogs, but no effects of month and geographic location were identified. These findings can assist clinicians in establishing diagnoses, and can assist breeders in defining priorities for preventative measures.     

Requirement for additional treatment for dogs with atopic dermatitis undergoing allergen-specific immunotherapy

Allergen-specific immunotherapy (ASIT) is one of the main treatments for atopic dermatitis in dogs, but it often requires additional treatments such as antibacterial and antifungal therapy for secondary bacterial and yeast infections, or antipruritic drugs to control the clinical signs or treat the adverse effects of the immunotherapy. Twenty-seven dogs enrolled in a study of ASIT were clinically assessed four times over a period of nine months; their requirement for treatment for secondary bacterial and yeast infections, for the administration of glucocorticoids as additional antipruritic therapy, and for the treatment of any adverse effects of the ASIT were evaluated. Twenty (74 per cent) of the dogs were treated for superficial bacterial pyoderma, 18 (66.6 per cent) required treatment for Malassezia species dermatitis on one or more occasions, eight (29.6 per cent) required treatment for otitis externa due to Malassezia species or bacteria, and eight required glucocorticoids to control their clinical signs. Five (18.5 per cent) of the dogs experienced adverse effects due to the ASIT and two required treatment with antihistamines (H1 receptor antagonists) in order to continue with the ASIT.