Heightened risk of canine chocolate exposure at Christmas and Easter

Chocolate has long been recognised as, and remains, a common cause of intoxication in dogs accounting for 25 per cent of acute presentations for intoxication.1 2 Case numbers in Europe and the UK have been reviewed, mostly based on reports to poisons centres.3–6 Chocolate toxicity results from the methylxanthine theobromine present in cocoa bean products, causing gastrointestinal (eg, vomiting), cardiovascular (eg, tachycardia) and central nervous (eg, agitation and seizure) signs.7 Chocolate intoxication is mostly seen in dogs6 8 and theobromine dose calculations based on the source of chocolate are well documented7 9 and available online. 10 11 The current study reviews cases of chocolate exposure presented to a large sentinel network of UK veterinary practices between 2012 and 2017. Electronic health records were collected from 229 UK veterinary practices (500 premises) by the Small Animal Veterinary Surveillance Network (SAVSNET).12 Records included the consultation time, species, breed, sex and clinical free text (narrative) in which inadvertent personal identifying data contained in narratives had been redacted using deidentification software (Newman). Narratives were screened using a regular expression13 to identify the presence of the word ‘chocolate’, including a range of misspellings and contractions (eg, ‘choc’, ‘choclat’). Cases were tagged for study inclusion if on reading they matched a definition of potential chocolate exposure whereby ingestion triggered either specific treatment or a plan of monitoring for clinical signs of theobromine toxicity. Data were wrangled using the Pandas library14 in Python V.3.415 and analysed using Stata V.12.16 Five unmatched controls were randomly selected for each case using animals not identified by the initial screening for chocolate. To analyse risk periods, a categorical variable was generated to indicate whether a consultation occurred from one week before to two weeks after Christmas, Easter, Valentine’s Day or Halloween. Univariable analysis of the effect of sex-neutering status, age category (0 to <4 years, 4 to <8 years, 8 years and over) and risk period was undertaken. Variables that showed a significant effect were included in a multivariable logistic regression model. The effect of breed was analysed using Fisher’s exact tests for each breed separately (to accommodate small numbers of individuals involved) and interpreting the P value following a Bonferroni adjustment. In total, 1722 consultations referring to chocolate were identified from 2.7 million narratives collected between November 2012 and May 2017 and of these 386 (22 per cent) narratives from 375 individual animals were identified as matching the chocolate exposure case definition. Where an animal appeared more than once, only the first consultation was retained. Many cases (101, 26 per cent) presented within one hour of ingesting chocolate and the majority (217, 56 per cent) presented within six hours. Vomiting following ingestion was frequently noted (64 cases, 17 per cent), while neurological signs (agitation, restlessness) were uncommon (12 cases, 3 per cent). Seizures were not reported in any cases. Heart rate greater than 120 bpm was noted in 28 cases (7.5 per cent). None of the clinical signs seen was considered life-threatening. Age category and risk period showed significant univariable effects and were included in a multivariable model. Chocolate exposure was significantly less common in old dogs (odds ratio (OR)=0.42, 95 per cent confidence interval (CI) 0.31 to 0.56, P<0.001) and potentially less common in middle-aged dogs (OR=0.77, CI 0.59 to 1.01, P=0.058) than dogs under four years of age. No breed was 10.1136/vr.104762