The characteristics of short- and long-term surviving Shiba dogs with chronic enteropathies and the risk factors for poor outcome

Abstract

Background: The objectives of this study were to investigate the differences in the characteristics of short- and long-term surviving dogs, and the factors that predict poor outcome in Shiba dogs with chronic enteropathies (CE).

Methods: A total of 25 Shiba dogs were included in this study, and classified as either short-term (≤6 months) survivors (Ss; n=16) or long-term (>6 months) survivors (Ls; n=9). The clinical and clinicopathological variables, histopathology, response to therapy, and outcomes were investigated between groups. Furthermore, these factors were tested for their ability to predict poor outcome.

Results: All CE dogs were diagnosed as having inflammatory bowel disease (IBD) with lymphocytic-plasmacytic enteritis (LPE). Age and canine inflammatory bowel disease activity index (CIBDAI) were significantly higher in the Ss group than in the Ls group (age: p = 0.035, CIBDAI: p = 0.018), as determined via univariate logistic regression analysis. According to receiver operator characteristic (ROC) curve analysis, the best predictors of poor outcome were age and CIBDAI, with the cutoffs determined as 7 years and 9 points, respectively. The majority of the cases (84%) responded to initial treatment; in particular, 75% of dogs in Ss group responded to therapy. The time to response (days) to the initial treatment in the Ss group (median 42.5 days, range: 20-91 days) was significantly shorter than that of the Ls group (median 285 days, range: 196-1026 days). Approximately half (55.5%) of the dogs in the Ls group died due to relapse of CE.

Conclusions: This study suggested that there is a high risk of early mortality in Shiba dogs with CE, particularly if the dogs are older (>7 years) and have a high CIBDAI score (>9 points). There appears to be a possibility of early mortality even if the initial treatment was efficacious. Furthermore, Shiba dogs with CE that become less responsive to initial therapy in the short-term (approximately 3 months) are more likely to have an early mortality. Thus, it is necessary to follow-up Shiba dogs with CE in the long-term, as approximately half of the long-term survivors eventually died due to a relapse of the signs.

Figure 1

The survival rates of the short-term (Ss) and long-term (Ls) groups, as represented by the Kaplan-Meier survival curves. The median number of survival days in the Ss group (73 days, range: 26-171) was significantly lower than that in the Ls group (800 days, range: 231-2204) (log-rank test p < 0.0001, Ss: n = 16, Ls: n = 9).

Figure 2

The cutoff value for age, as determined by receiver operator characteristic (ROC) curves. A cutoff value of 7 years was shown to be the best predictor for poor outcome, with a sensitivity of 0.7, a specificity of 0.78, and area under the curve (AUC) of 0.81 (p = 0.035, odds ratio (OR): 7.7, 95% confidence interval (CI): 1.1-51.2).

Figure 3

The cutoff value for CIBDAI, as determined by receiver operator characteristic (ROC) curves. A cutoff value of 9 was shown to be the best predictor for poor outcome, with a sensitivity of 0.88, a specificity of 0.68, and area under the curve (AUC) of 0.75 (p = 0.018, odds ratio (OR): 1.45, 95% confidence interval (CI): 1.1 -1.9). CIBDAI, canine inflammatory bowel disease activity index.