A retrospective study of horses investigated for weight loss despite a good appetite (2002–2011)

Summary Reasons for performing study: Weight loss despite a good appetite is a frequent diagnostic challenge for equine veterinarians; however, there are few objective reports and little descriptive information regarding risk factors and prognostic indicators. Objectives: To provide a descriptive epidemiological analysis of horses evaluated for weight loss despite a good appetite and evaluate relationships between historical and clinicopathological findings and final outcome (survival vs. nonsurvival) to identify risk factors and prognostic indicators. Methods: Medical records of horses referred for investigation of weight loss despite a good appetite were reviewed. Data collated included history, case details, clinical and diagnostic findings, diagnoses and outcome. Univariable associations were evaluated with a Mann–Whitney U test (continuous data), Fisher's exact test (categorical or binary data) or Pearson's rank correlation (continuous data), with P≤0.05 significant. Results: Forty cases met the inclusion criteria. Total protein (P = 0.004) and albumin concentrations (P = 0.0008) at admission were higher in survivors than nonsurvivors, with total protein ( r 2 = 0.31; P = 0.002) and albumin ( r 2 = 0.36; P = 0.0002) positively correlated with outcome. Hypoproteinaemic (P = 0.008, odds ratio (OR) = 12, 95% confidence interval (CI) = 1.99–72.4) and hypoalbuminaemic (P = 0.0009, OR = 28, 95% CI = 2.94–266.6) animals were at greater odds for nonsurvival. Body condition score was positively correlated with total protein (r 2 = 0.16; P = 0.05) and albumin (r 2 = 0.53; P<0.0001) concentrations at admission and duration of clinical signs (r 2 = 0.19; P = 0.03). Conclusions: The severity of hypoproteinaemia and hypoalbuminaemia were related with nonsurvival. Body condition score and albumin concentration could potentially be used as prognostic indicators for survival. Potential relevance: These findings highlight the importance of body condition assessment in conjunction with clinicopathological evaluation in horses with weight loss despite a good appetite.