Frequency, breed predispositions and other demographic risk factors for diagnosis of hypothyroidism in dogs under primary veterinary care in the UK

Abstract

Background Hypothyroidism is a commonly diagnosed endocrinopathy in dogs. This study aimed to investigate the frequency and risk factors for diagnosis of hypothyroidism in UK primary-care practice. Dogs diagnosed with hypothyroidism were identified by searching electronic patient records of primary-care practices participating in VetCompass. A cohort study design estimated one-year (2016) period prevalence and incidence risk for hypothyroidism. Multivariable binary logistic regression models were used to evaluate associations between demographic risk factors and hypothyroidism. Results From 905,553 dogs, 2,105 dogs were recorded with diagnosed hypothyroidism in 2016; 359 incident and 1,746 pre-existing, giving an annual prevalence of 0.23% (95% CI 0.22–0.24) and annual incidence risk of 0.04% (95% CI 0.04–0.04). Multivariable logistic regression identified 24 predisposed and nine protected breeds. Standard Doberman pinscher (odds ratio [OR] = 17.02, 95% CI 12.8–22.64), Tibetan terrier (11.25, 95% CI 8.27–15.32) and boxer (10.44, 95% CI 8.66–12.58) breeds showed high predisposition. Pug (OR 0.29, 95% CI 0.09–0.89), Yorkshire terrier (OR 0.38, 95% CI 0.24–0.59), Shih-tzu (OR 0.38, 95% CI 0.23–0.64) and Jack Russell terrier (OR 0.40, 95% CI 0.29–0.54) were the most protected breeds. Overall, being a purebred dog, being insured, having bodyweight above the breed-sex mean, increasing age, being neutered and rising adult bodyweight also showed increased odds being a dog living with a diagnosis of hypothyroidism. Conclusions Several strong breed predispositions for diagnosis of hypothyroidism were identified that can assist with disorder prioritisation in ongoing efforts to improve breed health. Other risk factors were also identified that can assist veterinary surgeons during clinical work-up of suspected cases. Identification of novel evidence for protected breeds provides useful information for research into genetic mechanisms.

Demography, common disorders and mortality of Boxer dogs under primary veterinary care in the UK

“…To build on this concept of evaluating disorder prioritisation within breeds based on both prevalence and predisposition, the current work also highlighted a relatively high prevalence for hypothyroidism, which affected 1.68% of the Boxer dogs in this study. Although this was only around one third of the prevalence for corneal ulceration, previous VetCompass work has reported the Boxer breed with the third highest prevalence of hypothyroidism and to have over 10 times the risk compared with crossbred dogs [ 17 ]. This comparison between corneal ulceration and hypothyroidism in Boxers highlights that even when a breed is highly predisposed to a certain disorder, a more prevalent disease leads to a higher disease burden and therefore may be considered as having a greater breed welfare impact.…”

“…In addition, a review of the wider literature in 2018 identified evidence of some predisposition to 86 disorders in Boxer dogs [ 16 ]. The breed has also featured in previous VetCompass publications, which have, for example, demonstrated a high Boxer breed predisposition for hypothyroidism [ 17 ] and corneal ulceration [ 18 ]. However, no single previous study has specifically investigated the health of Boxers across the full range of disorders using data harvested from primary-care veterinary clinics rather than owner reports (where the data may be distorted through information or social desirability bias) or insurance data (which are biased towards disorders that are not excluded from insurance cover) [ 19 ].…”

English Cocker Spaniels under primary veterinary care in the UK: disorder predispositions and protections

“…Ceruminous otitis in ECS could have contributed to the high odds of aural discharge in the current study (OR 14.66) but could also have been a clinical sign of hypothyroidism, a common trigger of otitis externa that debuts in middle-aged to older dogs and also affects the hair coat [ 46 , 53 ]. In our earlier ECS study, the prevalence of ear disorders in the ECS was shown to increase with age [ 11 ], and increased odds of hypothyroidism have been reported in the ECS, although the prevalence was low (0.37%) [ 16 ].…”

“…Predisposition describes an increased susceptibility to a certain disorder that could result from individual or combined risk factors such as genetics, conformation, sex, age, and environmental factors, while protection describes a reduced susceptibility [ 6 ]. The ECS has been reported in the literature as predisposed to several disorders including otitis externa [ 13 – 15 ], hypothyroidism [ 16 ], lipoma [ 17 ], mammary tumours [ 18 , 19 ], periodontal disease [ 20 ], non-neoplastic anal sac disorders [ 21 , 22 ], pancreatitis [ 22 , 23 ] and keratoconjunctivitis sicca [ 22 , 24 , 25 ]. Protections reported in the ECS include osteoarthritis [ 22 , 26 ], cruciate ligament disease [ 22 , 27 ], elbow and hip dysplasia [ 22 ], and skin-related disorders such as chronic itching, dermatitis, allergic skin disorder, and alopecia [ 22 ].…”

A Review of Clinical Outcomes, Owner Understanding and Satisfaction following Medial Canthoplasty in Brachycephalic Dogs in a UK Referral Setting (2016–2021)

“…A total of 494 candidate animals were manually reviewed. All clinical records were searched for potential inclusion using the clinical free text field (‘ medial canthoplasty ’, ‘ medial canth* ’, ‘ medial canthoplasties ’) [ 41 ]. The breeds of interest were selected during the time period of interest.…”