Renal disease can be defined as a heterogenous group of disorders in which one or both the kidneys loses their normal structure and function, which may be due to external or internal factors like infections, diabetes, auto immune diseases, cancer, other endocrine disorders and toxic chemicals
(Levey et al., 2013). It is characterized by the reduction in the excretory, regulatory and storage functions of the kidney. It is recognized now that even minor abnormal change in measures of kidney structure and function is associated with increased risk for development of other organ and system complications as well as mortality all of which occur far more frequently than kidney failure.
Renal disease is characterized by rapid onset of renal insufficiency within a week to 3 months or more, which results in inability of the kidneys to perform its normal functions like excretion, maintenance of homeostasis, perform biosynthetic endocrine function
etc.
(Chawla et al., 2020). This results in clinical manifestations such as depression, listlessness, vomiting, anorexia, diarrhoea, dehydration, uremic gastritis along with changes in the urine output.
Renal disease in dogs is considered as one of the leading causes of death and about 2-5% of dogs suffer with renal disease
(Lund et al., 1994). The prevalence is higher in geriatric dogs, with chronic renal insufficiency reaching a peak prevalence of 10% in veterinary clinical patients
(Polzin et al., 1992). This might be due to increased urbanization and environmental pollution, unscientific feeding and indiscriminate use of therapeutic agents. The variations in the occurrence could be due to several extrinsic factors like variations in geographical, environmental and managemental practices.
Now a days, the awareness among the pet owners as well as availability of advance diagnostic tools and therapeutic interventions make it possible to recognize the disorders related to renal function systematically. However, detailed reports on the occurrence of renal diseases in dogs of Assam are not available. Hence, the present study was conducted to record the occurrence of renal diseases in dogs that were presented to the Veterinary Clinical Complex, College of Veterinary Science, Khanapara, Guwahati, Assam.
Ethics statement
The study was conducted on dogs bought to Veterinary Clinical Complex, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, Assam, India for routine diagnostic examination. Therefore, it does not require the approval from the Institutional Animal Ethics Committee.
Animals
The present study was carried out on all the dogs registered at Veterinary Clinical Complex, from January 2018 to December 2022. Dogs presented with the history and symptoms of chronic vomiting irrespective of food and water intake, inappetence, anorexia, halitosis, oral ulcerations, variation in mucous membrane colour ranging from pale to congested, gastritis, loose and blackish stool, changes in urine output and urine frequency, dehydration, lethargy, weight loss etc. were screened for renal diseases. Dogs having haemoprotozoan infections (
Babesia gibsoni and
Ehrlichia canis) and bacterial infections (
Leptospira species) were also screened for renal diseases. During the study period, a total of 1,67,077 dogs were registered, out of which 17,999 were screened for renal diseases on the basis of patient’s history and on the above-mentioned clinical signs and symptoms. Furthermore, the suspected dogs were subjected to routine urine analysis, haemato-biochemical analysis and diagnostic study (imaging techniques like radiography and ultrasonography) for confirmatory diagnosis of renal diseases. The occurrence of renal failure was recorded with respect to breed, sex and age.
Study period
The present study was conducted for a period of 5 years
i.
e from January 2018 to December 2022 at Veterinary Clinical Complex, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati, Assam, India.
Prevalence rate
The retrospective study of prevalence of renal diseases in dogs presented for the last five years (1
st January 2018 - 31
th December 2022) was performed on the basis of breed, Sex and Age.
Prevalence of renal disease was calculated by the following formula:
Statistical analysis
Statistical analysis was done using The GraphPad Prism Version 10.0 for Windows, GraphPad Software, La Jolla California USA, www.graphpad.com. Differences were considered to be significant at P<0.05 and P<0.01. The differences between the groups were analysed by “Chi-square test”.
Renal failure is the one of the most common and fatal condition occurring in dogs. The etiological factors involved in dogs affected with renal failure were urolithiasis, leptospirosis, pyometra and many other unknown causes (idiopathic).
During the study period, a total of 1,67,077 dogs were registered, out of which 4,594 dogs were confirmed for renal diseases. The overall prevalence of renal disorder was found to be 2.74 % for the said period (Fig 1). The prevalence of renal diseases was found to be highest in the year 2021 followed by year 2022 and lowest in the year 2018.
In this retrospective study, the prevalence rates of renal disease were found to be following an increasing trend with the advancement of time
i.
e. from year 2018 to 2021. However, the prevalence of renal disease in year 2022 was found to be slightly lower than the prevalence rate observed in year 2021 (Fig 2). This may be due to development of more specific diagnostic protocols as well as due to the increasing awareness among the dog owners regarding their pet’s healthy lifestyle. These findings were consistent with earlier finding
(Tufani et al., 2017) whereas other researchers reported slightly higher overall occurrence of renal diseases in dogs as 3.48% and 4.84%
(Chawla et al., 2020) respectively.
The variation observed in prevalence rates in different studies might be due to variations in geographical area considered for the study, population size as well as on the variations in the period of study.
Breed-wise occurrence
The study period includes many different breeds, amongst them, the occurrence of renal disorder was found to be highest in Labrador retriever (29.71%) breed followed by non-descript breed (17.22%) and lowest in English pointer (0.04%) followed by Shitzu (0.09%) and American bulldog (0.13%) (Table 1). In this study the calculated chi-square value was 132.50 at a significance level of 1% (p<0.001) for the years 2018-2022. Similar findings were reported by various researchers who reported the highest prevalence of renal diseases in Labrador Retriever breed of dogs
(Tufani et al., 2017; Nabi et al., 2018; Chaitanya et al., 2020; Chawla et al., 2020; Sahu et al., 2021; Ahmad et al., 2023 and
Bilwal et al., 2024) and also highest prevalence of chronic kidney disease in Labrador Retriever breed of dogs
(Reddy et al., 2021). These findings were inconsistent with other findings that report highest occurrence of renal diseases in Pomeranian breed followed by Labrador retriever
(Karunanithy et al., 2019); and highest prevalence (28.20%) of renal disorders in the breeds of Spitz
(Thade et al., 2019).
The variation in breed wise occurrence of renal disease may be due to prevalence of particular breed of dogs in a particular geographical area.
Sex-wise occurrence
The occurrence of renal disease was found to be higher in males (60.08%) than female dogs (39.92%) and the female: male ratio ranges from 1: 1.26 to 1: 1.79. The overall female: male ratio is found to be 1: 1.50 ratio for the years 2018 to 2022 (Table 2) and the calculated chi-square value was 20.27 at a significance level of 1% (p<0.001) for the years 2018-2022. This finding was in accordance with other reports
(Tufani et al., 2017; Chawla et al., 2020; Kumar et al., 2020; Meena et al., 2022; Ahmad et al., 2023 and
Bilwal et al., 2024).
Higher occurrence of renal diseases in males may be due to anatomical differences in kidneys (size and volume) as well as in urinary tract of male which helps in advancement of the disease. Due to anatomical differences in urinary tract, male dogs are more prone to urolithiasis and prostate diseases where an inflamed prostate gland affects the normal flow of urine. Moreover, male dogs known to have higher blood pressure than the females which might also be responsible for its higher prevalence. One of the reasons for higher occurrence of renal diseases in male dogs may be due to preference of dog owners towards male dogs as pets. However, some researchers reported higher occurrence of the disease in females than males
(Nabi et al., 2018 and
Chaitanya et al., 2020).
Age-wise occurrence
The dogs in the age group of > 6-10 Years (31.74%) were mostly affected with renal disorders followed by age group of >3-6 Years (26.38%) and the dogs of age group ≤ 1Year (6.79%) were least affected during the entire period
i.
e. from January 2018 to December 2022 (Table 3). The Calculated chi-square value was found to be 47.80 at a significance level of 1% (p<0.001, 0.0001) for the years 2018-2022. Various researchers have reported higher occurrence or prevalence of renal diseases in older dogs
(Reddy et al., 2021; Sahu et al., 2021; Ahmad et al., 2023 and
Bilwal et al., 2024). This could be attributed to the loss of functional nephrons of the kidney and reduced renal blood flow with the advancement of age
(Polzin et al., 1992 and
Sahu et al., 2021). Moreover, older dogs often have other age-related issues that may play a role in leading them to renal disorders. However, the occurrence of renal diseases in dogs of age group >10 years is comparatively lower than the other age groups except puppies because only a small percentage of dogs of above 10 years of age were registered during the study period.
