3.1. Factor Analysis of the ProQOL Scale
A confirmatory factor analysis (CFA) was conducted to test the original three-factor structure of the ProQOL (
Stamm, 2010). The model showed poor fit to the data (χ
2 (405) = 1190.34,
p < 0.001; CFI = 0.595; TLI = 0.565; NFI = 0.498; RMSEA = 0.117; PNFI = 0.464; IFI = 0.601; AIC = 11,606.56; BIC = 11,780.88), indicating that the original three-factor solution was not supported. Based on modification indices (MIs), item loadings, and semantic redundancy, a more parsimonious model with 11 items grouped into two factors—compassion fatigue (CF) and compassion satisfaction (CS)—was retained. This model demonstrated an acceptable fit (χ
2 (43) = 122.21,
p < 0.001; CFI = 0.888; TLI = 0.857; RMSEA = 0.117 [90% CI: 0.093–0.141]; SRMR = 0.080), supporting its adequacy despite the slightly elevated RMSEA.
The factor loadings were adequate (≥0.45; see
Table 2), and the negative covariance between CF and CS (r = −0.285,
p = 0.012) confirms that both dimensions are opposite but related. The reliability (α = 0.87 and 0.83; total Ω = 0.92 and 0.87) and convergent validity (AVE = 0.54 and 0.53) analyses were satisfactory.
Discriminant validity was also supported, as the criterion of
Fornell and Larcker (
1981) was met: the square root of AVE was greater than the correlation between factors (√AVE_HR = 0.737; √AVE_CS = 0.725; r = −0.285), supporting that CF and CS are distinguishable constructs.
Finally, a model with a general factor (items loading on a general factor of emotional impact and its specific factors) showed lower fit and reliability than the two-factor correlated model. Therefore, the shared variance is better explained by the specific factors CF and CS, without a general factor dominating the structure.
3.2. Cluster Analysis
3.2.1. Cluster Identification
For exploratory purposes, we first ran a hierarchical cluster analysis (average linkage/UPGMA; rescaled Euclidean distance). The dendrogram suggested a four-cluster solution. The cophenetic correlation was 0.662, indicating moderate fit; therefore, we refined the partition with a k-means (k = 4) seeded from the hierarchical solution.
This analysis identified four distinct profiles based on CF and CS scores:
Cluster 1 (n = 37; 27.4%) was characterized by above-average scores in both dimensions, suggesting intense emotional involvement.
Cluster 2 (n = 36; 26.7%) showed low scores on both dimensions, consistent with a profile of emotional detachment.
Cluster 3 (n = 31; 23%) showed a low level of CF and moderate CS, consistent with functional distancing.
Cluster 4 (n = 31; 23%) combined a high level of CF with low CS, constituting a high emotional risk profile.
Figure 1 displays the individual factor z-scores, the spatial delimitation of each cluster and their centroids, allowing inspection of distribution and relative overlap across profiles.
3.2.2. Validation and Robustness of the Clustering Solution
To examine the stability of the classification obtained, the resampling procedure with replacement (cluster boot) was applied to the K-means analysis, calculating the Jaccard index for each cluster. The results showed acceptable stability in cluster 1 (J = 0.69), but lower levels in the remaining clusters: cluster 2 (J = 0.51), cluster 3 (J = 0.34), and cluster 4 (J = 0.52), probably because of profile overlaps and the smaller cluster sizes.
The graphical representation of the mean profiles (standardized means of each variable per cluster; see
Figure 2) showed patterns consistent with the theoretical interpretation presented in the previous point.
To evaluate the quality of the four-cluster solution, the silhouette index was calculated for each case, as well as the mean value for the entire structure, which was 0.51. The mean silhouette values across clusters ranged from 0.49 (cluster 1) to 0.53 (cluster 4), indicating a reasonably well-defined configuration in which individuals were closer to members of their own cluster than to those of other clusters. None of the clusters presented negative or near-zero values, confirming the internal cohesion and interpretability of the four-group solution.
Overall, these results suggest that the four-cluster solution presents an interpretable and stable structure suitable for segmenting the emotional profiles of veterinarians. This segmentation provides a solid basis for a more detailed analysis of differences and relationships with other variables.
3.2.3. Discriminant Analysis
A linear discriminant analysis was performed to determine whether the standardized scores for fatigue (ZCF) and compassion satisfaction (ZCS) could reliably differentiate between clusters. The dependent variable was membership in one of the clusters. Equal probabilities were assumed, and the intragroup covariance matrix was used.
The test of homogeneity of covariance matrices (Box’s M) was not significant (F = 1.065; p = 0.311), supporting the validity of the linear model under the assumption of equal covariances between clusters.
The analysis generated three discriminant functions, of which only the first reached statistical significance (Λ de Wilks = 0.250; χ2 (6) = 165.51; p < 0.001), explaining 89.3% of the total variance. The second and third functions were not significant (p = 0.454 and p = 0.963, respectively).
The first discriminant function, with a canonical correlation of 0.798, showed strong power of separation between clusters, determined mainly by HR (structural coefficient = 0.948), while HRV contributed secondarily and inversely (structural coefficient = −0.284). This pattern suggests that high levels of CF and low levels of CS characterize the profiles with the highest emotional risk.
The analysis of the centroids showed a clear progression along the first function: cluster 3, the very low risk cluster, had the most negative value (−2.531), followed by cluster 2 (−0.793), the low-moderate risk cluster, followed by cluster 1 (1.144), which represents moderate-high risk, and cluster 4 (2.18), which represents very high risk. This distribution indicates that the function effectively discriminates in the direction of increasing emotional risk.
The correct classification rate reached 88.1% in the original sample and remained high after applying cross-validation using the “leave one out” procedure (87.4%). In both cases, the classification was particularly accurate in the extreme groups: the very low-risk cluster (No. 3) was correctly classified in 96.3% of cases, and the very high-risk cluster (No. 4) in 93.5%. The intermediate groups also showed satisfactory classification rates (cluster 2: 79.4%; and cluster 1: 83.3%).
These results show that the combination of ZCF and ZCS effectively discriminates between different levels of emotional risk. CF emerges as the most powerful predictor in the discriminant structure, while CS provides a complementary nuance.
The high classification rate empirically validates the identified cluster structure and suggests that these dimensions can be used for diagnostic or screening purposes in professional populations at risk of emotional exhaustion.
3.2.4. GLM Differences Between Clusters
A general linear multivariate analysis (GLM) was performed to examine whether there were significant differences in levels of compassion fatigue (CF) based on the emotional profiles identified by cluster analysis, controlling for the effect of sociodemographic variables: gender, dichotomous age, and cohabitation. The CF score was introduced as a continuous dependent variable, derived from the AFC and therefore conceptually suitable for use in GLM models.
The model results indicated a significant main effect of the clustering factor on CF, even after controlling for covariates (F (3,127) = 125.24, p < 0.001, partial η2 = 0.747), implying a very high effect size.
The sociodemographic covariates did not reach individual statistical significance, although cohabitation showed a marginal trend (p = 0.064, partial η2 = 0.027), suggesting a possible weak moderating influence on fatigue levels.
Levene’s test was significant for the HR variable (F (3,130) = 2.690, p = 0.049), indicating some heterogeneity of variances. However, given the relatively balanced sample size per cluster, the interpretation based on post hoc comparisons with Sidak correction was maintained.
The estimated marginal means (adjusted for age, sex, and partner) revealed clear differences between profiles, as shown in
Table 3 and graphically represented in
Figure 3, allowing for a more accurate observation of the magnitude of the differences while controlling for covariates.
All pairwise comparisons between groups were statistically significant (
p < 0.001) with large differences between group 4 and the rest. The following table shows the adjusted mean differences in CF between groups (see
Table 4).
Overall, the results confirm that differences in CF between the identified emotional profiles cannot be attributed to age, gender, or marital status. These differences remain robust even when controlling for individual variability in these covariates, reinforcing the validity of emotional typology as a differentiating criterion in fatigue risk.
3.3. Predictive Value of Sociodemographic Variables: Ordinal Regression Model
In order to examine the extent to which the sociodemographic variables recorded predict perceived emotional risk, an ordinal regression analysis was performed. The dependent variable was membership in one of the four clusters, which were classified hierarchically according to perceived emotional severity based on CF and CS scores, from lowest to highest: (1) functional distancing, (2) emotional detachment, (3) intense emotional involvement, and (4) high emotional risk.
The PLUM (Polymeric Universal Model) procedure was applied with a cumulative logit link function, assuming that the proportional odds hypothesis was satisfied. The predictive variables were gender (0 = male, 1 = female), dichotomized age (0 = ≤44 years, 1 = >44 years), and cohabitation (0 = no, 1 = yes). The reference category was the profile with the lowest emotional severity (functional distancing).
Initially, a complete model was estimated that included all first-, second-, and third-order interactions between the predictor variables. However, this model was not significant (χ2= 32.038; df = 21; p = 0.058), so a more parsimonious model focused on the main effects was chosen.
The final model showed an adequate fit (χ2 = 15.963; df = 3; p = 0.001), with moderate explanatory power according to the pseudo-R2 coefficients: Cox and Snell = 0.113, Nagelkerke = 0.125, and McFadden = 0.047. Similarly, the parallel lines test was not significant (χ2 = 9.707; df = 6; p = 0.137), confirming the validity of the probability proportionality hypothesis and justifying the use of the ordinal model.
In terms of individual effects, gender did not reach statistical significance (B = 0.169;
p = 0.518; OR = 1.184), suggesting that there is no clear difference between men and women in the risk of belonging to more severe emotional profiles. In contrast, age and cohabitation were significantly associated with this risk. Specifically, participants over the age of 44 were more than twice as likely to belong to higher-risk profiles (B = 0.744;
p = 0.011; OR = 2.105), as were those who lived with their partner (B = 0.662;
p = 0.023; OR = 1.938). The model coefficients, along with their 95% confidence intervals, are presented in
Table 5.
3.4. Qualitative Analysis of Open-Ended Comments
The open-ended comments provided by participants at the end of the questionnaire (n = 31) generated a total of 54 units of analysis, as several of them expressed more than one form of discomfort. Using inductive categorical analysis of multiple responses, these units were classified into six main thematic categories by two independent judges, who resolved their disagreements by consensus.
These categories and their relative frequencies are summarized in
Table 6, which constitutes the codebook of the qualitative analysis. The most frequent themes referred to lack of professional recognition, conflicts with owners, and work overload, followed by reports of disrespectful treatment, vocational ambivalence, and isolated mentions of suicidal ideation.
Since this is a multiple-response analysis, the cumulative percentages exceed 100% (174.2%), indicating that a significant proportion of participants reported distress in more than one category. This pattern of concurrence allows for a more nuanced and richer understanding of the experiences of professional distress in the sample analyzed.
To explore the relationships between these categories, a semantic network of co-occurrences was constructed using the Jaccard similarity coefficient as a measure of thematic proximity.
Figure 4 shows this network, in which each node represents a category of discomfort and each edge indicates the strength of overlap between two categories, based on the value of the Jaccard coefficient. The higher this value, the more frequently participants mention both categories together.
The numerical values next to each node indicate the weighted degree of its frequency; that is, the sum of the similarity coefficients with the other categories in the network. This measure allows us to identify which categories play a more central or articulating role in the discourse of discomfort. In this sense, lack of recognition stands out as the most central node (weighted degree = 0.992), followed by conflicts with owners (0.852), work overload (0.787), and humiliating treatment (0.597). These four categories form a dense relational core that predominantly structures the narratives of discontent.
In contrast, vocational satisfaction, with a weighted score of 0.106, appears in a peripheral position, weakly connected to the rest of the network, suggesting that positive or resilient content is rarely expressed alongside explicit forms of discontent. The category of suicidal ideation, although not shown in the figure due to its low connectivity, did not occur alongside any other label, reinforcing its isolated nature and suggesting a specific vulnerability profile.
Sentiment analysis, performed using the NRC Emotion Lexicon adapted to Spanish, confirmed the predominance of negative emotions in the collected discourses. The most frequent were anger, sadness, and disgust, followed by fear. In contrast, positive emotions such as joy, confidence, and anticipation were rarely mentioned. This affective pattern reinforces the interpretation of the comments as expressions of accumulated distress, professional discontent, and emotional exhaustion.
From an explanatory perspective, the relationship between sociodemographic variables and the degree of verbalized distress was explored. The ordinal regression model showed that age was a significant predictor of the number of categories of distress expressed (χ2 = 8.235; p = 0.004), with a higher accumulation in professionals aged 44 or younger (B = 2.485; 95% CI = 0.788–4.181). Living with a partner had a marginally significant effect (χ2 = 3.844; p = 0.050), with a negative association (B = −1.585; 95% CI = −3.169 to −0.001), suggesting that those who do not live with a partner tend to verbalize a greater number of complaints. Gender was not found to be a significant predictor (χ2 = 0.472; p = 0.492).
Regarding the binary logistic regression model to predict the group with high CF, the variable «lack of recognition» emerged as a marginal predictor (B = −22.472; p = 0.998; OR = 0), although this estimate lacks numerical stability and should be interpreted with caution. The model showed a modest fit (Nagelkerke’s R2 = 0.166) and a correct classification rate of 67.7%.
Finally, multinomial logistic regression revealed that the set of distress categories allows for significant discrimination between the different clusters (χ2 [18] = 43.57; p < 0.001; Nagelkerke’s R2 = 0.820).