Brenda N. Bonnett

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.

Mortality in over 350,000 Insured Swedish dogs from 1995–2000: I. Breed-, Gender-, Age- and Cause-specific Rates

This study presents data on over 350,000 insured Swedish dogs up to 10 years of age contributing to over one million dog-years at risk (DYAR) during 1995–2000. A total of 43,172 dogs died or were euthanised and of these 72% had a claim with a diagnosis for the cause of death. The overall total mortality was 393 deaths per 10,000 DYAR. Mortality rates are calculated for the 10 most common breeds, 10 breeds with high mortality and a group including all other breeds, crudely and for general causes of death. Proportional mortality is presented for several classifications. Five general causes accounted for 62% of the deaths with a diagnosis (i.e. tumour (18%), trauma (17%), locomotor (13%), heart (8%) and neurological (6%)). Mortality rates for the five most common diagnoses within the general causes of death are presented. These detailed statistics on mortality can be used in breed-specific strategies as well as for general health promotion programs. Further details on survival and relative risk by breed and age are presented in the companion paper [14].SammanfattningMortalitet hos hund baserad på data från över 350 000 svenska hundar försäkrade under 1995 till 2000: 1. Ras-, ålders-, köns- och orsaksspecifika rater.I denna studie presenteras data från över 350 000 försäkrade svenska hundar, med en ålder upp till 10 år, som tillsammans har bidragit med över en miljon hundår av risk (HÅR) under åren 1995 till 2000. Totalt dog eller avlivades 43 172 hundar. Av dessa hade 72% fått en dödsorsaksdiagnos. Den totala mortaliteten var 393 dödsfall per 10 000 HÅR. Mortalitet ututräknades generellt och per dödsorsak för de 10 vanligaste hundraserna, för 10 hundraser med hög mortalitet och för en övrig grupp. Flera typer av proportionell mortalitet presenteras. Fem generella orsaker stod för 62% av alla dödsfall där diagnos förelåg – tumörer (18%), trauma (17%), problem från rörelseapparaten (13%), hjärta (8%) och neurologiska problem (6%). Mortaliteten för de fem vanligaste diagnoserna inom de generella dödsorsakerna presenteras. Denna detaljerade mortalitetsstatistik kan användas både för rasspecifika strategier och för mer generella hälsobefrämjande åtgärder.

Associations of clinical findings, bacteriological and histological results of endometrial biopsy with reproductive performance of postpartum dairy cows

Abstract Ninety-seven cows from a commercial Holstein-Friesian dairy herd were studied. Cows were classified as having exhibited good or poor reproductive performance. Unconditional relationships were examined between prostaglandin administration, clinical and palpation findings and histological and bacteriological culture results of endometrial biopsies taken at Days 26 and 40 postpartum and the reproductive performance variable. Variables unconditionally associated with performance were then offered to logistic multiple-regression models to quantify the diagnostic efficacy of these findings. Logistic regression models were calculated for histological, bacteriological, and clinical findings (at Days 26 and 40) first separately and then in a combined model. Cows positive for Actinomyces pyogenes or anaerobic bacteria were more likely to be poor reproductive performers. Variables from Day 26 postpartum were more likely to be conditionally associated with reproductive performance than findings from Day 40. Ovarian findings from Day 26 were associated with subsequent reproductive performance only when the location of the structure relative to the previously gravid horn was considered. In the final combined model, increased inflammation in the stratum compactum and more areas of epithelium increased the likelihood of poor reproductive performance, and increased numbers of lymphocytic foci in the stratum compactum and larger follicles on the gravid-side ovary reduced the risk of poor reproductive performance. This model included information on 55 cows and achieved 84% correct predictions, with a sensitivity (for poor cows) of 92% and a specificity (good cows) of 77%.

Mortality in insured Swedish dogs: rates and causes of death in various breeds

Data on over 222,000 Swedish dogs enrolled in life insurance in 1992 and 1993 were analysed. There were approximately 260 deaths per 10,000 dog-years at risk. Breed-specific mortality rates and causes of death are presented for breeds with more than 500 dogs at risk that had consistently high or low rates. Breed-specific mortality ranged from less than 1 per cent to more than 11 per cent. True rates and proportional statistics for the cause of death were calculated for the entire insured population (250 breeds) and cause-specific mortality rates were calculated for the breeds with the highest risk of dying of the most common causes. Trauma, tumours and problems related to the locomotor system together accounted for more than 40 per cent of all deaths or euthanasias. Although limited to insured dogs, these data cover approximately one-third of all Swedish dogs and provide baseline mortality data for further population-based studies on health and disease.

Validation of computerized Swedish dog and cat insurance data against veterinary practice records

Large computerized medical databases offer great potential for epidemiological research. However, data-quality issues must be addressed. This study evaluated the agreement between veterinary practice records and computerized insurance data in a large Swedish claims database. For the year 1995, the company insured over 320,000 dogs and cats. A total of 470 hard-copy records were sampled from claims for health care (n = 236) and life insurance (n = 234). Computerized insurance data for these claims were accessed and records from the attending veterinary practices were collected. For health and life claims, respectively, 79.2 and 72.8% of practice records were retrieved. Variables compared between the computer and practice records were breed, sex, date of birth and diagnosis for the claim. The degree of agreement was categorized as agreement, minor disagreement, major disagreement or data missing. Multivariable logistic regression was used to examine factors associated with errors. The observed agreement for breed and sex was excellent. There was 28.9 and 33.8% minor disagreement for the date of birth for health and life claims, respectively. This was mainly because, prior to 1993, the date of birth was coded as the first of January when more complete information was unavailable. Major disagreement (different year of birth) was low for both health and life claims. For health and life claims, the observed agreement for diagnosis was 84.0 and 84.9%, minor disagreement was 6.4 and 4.3%, and major disagreement 5.9 and 9.4%, respectively. Although there was no difference based on size of the veterinary clinic involved, there was a tendency for better agreement between the practice record and the computerized insurance data for claims from clinics with computerized practice records (n = 40) than for clinics with manual practice records (n = 286). Rates of discrepancy were affected by the clerk who processed the claims. Records processed by two of the 21 clerks had significantly more disagreements. Given the nature of the data, it was only possible to calculate a measure of observed agreement. In general, the agreement between data in the insurance-company database and from the practice records was excellent for demographic data such as breed and sex and fair for diagnostic information and date of birth. In general, the data are adequate to support ongoing research with due considerations of certain limitations.

Mortality in over 350,000 Insured Swedish Dogs from 1995–2000: II. Breed-Specific Age and Survival Patterns and Relative Risk for Causes of Death

This study continues analysis from a companion paper on over 350,000 insured Swedish dogs up to 10 years of age contributing to more than one million dog-years at risk during 1995–2000. The age patterns for total and diagnostic mortality and for general causes of death (trauma, tumour, locomotor, heart and neurological) are presented for numerous breeds. Survival estimates at five, eight and 10 years of age are calculated. Survival to 10 years of age was 75% or more in Labrador and golden retrievers, miniature and toy poodles and miniature dachshunds and lowest in Irish wolfhounds (91% dead by 10 years). Multivariable analysis was used to estimate the relative risk for general and more specific causes of death between breeds accounting for gender and age effects, including two-way interactions. Older females had tumour as a designated cause of death more often than males in most breeds, but not in the Bernese mountain dog. Information presented in this and the companion paper inform our understanding of the population level burden of disease, and support decision-making at the population and individual level about health promotion efforts and treatment and prognosis of disease events.SammanfattningMortalitet hos hund baserad på data från över 350 000 svenska hundar försäkrade under 1995 till 2000: II. Rasspecifika ålders och överlevnadsmönster och relativ risk för olika dödsorsaker.Detta är del 2 i en studie där data på över 350 000 försäkrade svenska hundar under 10 års ålder analyserats. Resultaten grundas på mer än en miljon hundår av risk under 1995 till 2000. Åldersmönstret för den totala och diagnostiska mortaliteten, och också för generella dödsorsaker (trauma, tumörer, problem från rörelseapparaten, hjärta och neurologiska problem) presenteras för ett flertal hundraser. Beräknad överlevnad vid 5, 8 och 10 års ålder presenteras. Överlevnaden vid 10 års ålder var 75% eller högre hos labrador och golden retriever, dvärg- och mellanpudel samt dvärgtaxar och lägst hos irländska varghundar (91% var döda vid 10 års ålder). Multivariabel analys användes för att beräkna relativ risk för generella och mer specifika dödsorsaker för olika raser, med hänsyn taget till könsoch ålderseffekter vilket också inkluderar två-vägs interaktioner. I de flesta hundraser hade äldre tikar tumör som dödsorsak oftare än äldre hanhundar, med undantag för berner sennen hundar. Information som presenteras i denna del (2) och del 1 ger insikt om dödsorsakspanoramat hos hund. Detta kan ge stöd för beslut på både populations och individuell nivå om vilka åtgärder somkan vidtas för att förbättra hundars hälsa, såväl behandlingsmässigt som prognostiskt.

Gender, age, breed and distribution of morbidity and mortality in insured dogs in Sweden during 1995 and 1996.

More than 200,000 dogs insured by one Swedish company at the beginning of either 1995 or 1996 were included in a retrospective, cross-sectional study. They could be covered for veterinary care at any age, but were eligible for life insurance only up to 10 years of age. Accessions for veterinary care that exceeded the deductible cost were used to calculate the risk of morbidity. The morbidity and mortality data have been stratified by gender, age, breed, location and human population density. In each year, 13 per cent of the dogs experienced at least one veterinary care event and the mortality risk was 3-0 per cent. The risk of morbidity varied with age, gender, breed, and location. The risk of mortality increased principally with age. It was possible to derive population-based risks of morbidity and mortality from these insurance data.

Validation of a Neospora caninum iscom ELISA without a gold standard.

Neospora caninum is an intracellular parasite which causes abortion in cattle worldwide. One problem in the validation of the different methods for demonstration of this parasite is the lack of an appropriate gold standard. To validate an immunostimulating complex (iscom) enzyme-linked immunoassay (ELISA) used to detect antibodies to N. caninum, sera from 244 cattle in five Swedish dairy herds infected with N. caninum were analysed. The sera also were analysed by a standard indirect-fluorescent antibody test (IFAT). The results obtained by the two tests were compared using the Gibbs sampler. Gibbs sampling is a latent-class approach based on Bayesian statistics; neither test is assumed to be more correct in stating the true status of infection. The Gibbs sampler was run using both informative and non-informative prior probabilities. We also simulated different cut-offs in the iscom ELISA (providing data to inform selection of optimal cut-off values for different applications). The ELISA produced fewest incorrect test results over all at a cut-off value of 0.200. The sensitivity and specificity at this cut-off were 99 and 96%, respectively. The IFAT had a high specificity (99%) but a lower sensitivity (78%) than expected-confirming that the IFAT cannot be treated as a true gold standard. Sensitivity and specificity of the ELISA were presented in a two-graph receiver operating characteristic (TG-ROC) plot. Any cut-off between 0.150 and 0.300 will have both sensitivity and specificity > or =95%. Optical densities of < or =0.150 and > or =0.550 (or > or =0.350) were suggested as limits to rule out and rule in infection, respectively.

Mortality of swedish horses with complete life insurance between 1997 and 2000 : variations with sex, age, breed and diagnosis

The aim of this study was to evaluate the potential usefulness of the database maintained by the Swedish insurance company Agria for providing mortality statistics on Swedish horses. Mortality statistics (incidence rates and survival) were calculated, both crudely and stratified by sex, age, breed, breed group and diagnosis, for the horses with complete life insurance, which covers most health problems. The total mortality was 415 (95 per cent confidence interval [CI] 399 to 432) deaths per 10,000 horse-years at risk, and the diagnostic mortality, including only deaths with an assigned diagnosis, was 370 (95 per cent CI 355 to 386) deaths per 10,000 horse-years at risk. The diagnostic mortality of geldings was 459 (95 per cent CI 431 to 487), of mares 345 (95 per cent CI 322 to 365) and of stallions 214 (95 per cent CI 182 to 247) deaths per 10,000 horse-years at risk. The mortality rates increased with age and differed widely between breeds. Survival analysis showed that the median age at death of the horses enrolled before they were one year of age was 18·8 years. The most common cause of death or euthanasia was joint problems, which were responsible for 140 (95 per cent CI 130 to 149) deaths per 10,000 horse-years at risk. The results of multivariable models developed by using Poisson regression generally agreed well with the crude results.

Age pattern of mortality in eight breeds of insured dogs in Sweden

The objective of this study was to use several methods to describe the age patterns for risk of death in selected breeds of dogs insured for life in a Swedish animal-insurance company in 1996. Data on eight breeds were analyzed for age at death (including euthanasia). If dogs left the insurance for reasons other than death, they were regarded as censored. Dogs were only insured up to 10 years of age. Four analytical approaches were used. First, descriptive statistics of age distributions (e.g. breed-specific median ages at death, breed- and age-specific mortality risks) were computed. Second, age-specific estimates of survival were calculated using the formula: survival=(1-risk(age<1 year))(1-risk(age 1<2 year))... (1-risk(age 9<1 0 year)). Third, Cox regression (proportional-hazards model) was used to estimate survival and hazard functions. Finally, hierarchically coded Poisson regression was used to determine age-specific cut-points in the risk of death. The hazards from Cox and the incidence-density rates from the hierarchically coded models were transformed to estimates of risk: risk=1-exp¿-(hazard)¿ or 1-exp¿-(incidence-density rate)¿. The breeds studied were Beagle, Bernese mountain dog, Boxer, Cavalier King Charles spaniel, Drever, German shepherd dog, Mongrel and Poodle, together representing over 50000 dogs each year. The yearly breed-specific mortality risk varied between 1.7% (Poodle) and 6.5% (Bernese mountain dog). In all breeds, the risk of death increased with age but the pattern varied by breed. The probability of survival at 5 years of age varied between 94% (Cavalier King Charles spaniel and Poodle) and 83% (Bernese mountain dog, Drever, German shepherd dog) and the survival at 10 years between 83% (Poodle) and 30% (Bernese mountain dog). The survival estimates from Cox and those derived using the combined-risk formula were similar. The cut-point risk estimates provided a simplified picture of when the risk of death changed significantly compared to previous age categories. As anticipated, breeds differed widely in survival up to 10 years of age and there were marked differences in age patterns of mortality. The implications of these findings should be considered in multivariable analyses, where the confounding effect of age is often controlled for using a single age variable common to several breeds.