An international multi-centre cohort study of weight loss in overweight cats: Differences in outcome in different geographical locations

<div><p>Introduction</p><p>Feline obesity is a worldwide concern which has recently been formally classified as a disease by the veterinary community. Management involves invoking controlled weight loss by feeding a purpose-formulated food in restricted quantities and altering physical activity. Most weight loss studies conducted in cats have been undertaken in research cat colonies from single geographic locations. The aim of this multi-centre cohort study was to determine the efficacy of a short-term dietary weight loss intervention in overweight pet cats across a range of geographical locations globally.</p><p>Materials and methods</p><p>A 3-month (median 13 weeks, inter-quartile range [IQR] 12–15 weeks) weight loss programme was conducted at 188 veterinary practices in 22 countries, and involving 730 cats, 413 of which completed the programme and had complete data available. All were fed commercially available dry or wet weight loss diets, and median energy intake was 53 kcal/kg BW^0.711/day. The Royal Canin Ethics Committee approved the study, and owners gave informed consent. Owners completed behavioural questionnaires assessing begging, physical activity and quality of life (QOL). Linear mixed models were used to assess the respective influence of time, age, and initial body condition score (BCS) on weight loss and behavioural observations.</p><p>Results</p><p>At baseline, median age was 72 months (range 12–200 months) and median BCS was 8 (range 7–9). In all, 402/413 cats (97%) lost weight (mean 10.6±6.3%) during the programme at a rate of 0.8 ±0.50%/week. Based upon owner questionnaires, activity and QOL improved (both <i>P</i><0.001), while begging behaviour decreased <i>(P<</i>0.001) during weight loss. The main factor influencing percentage weight loss was geographical location (<i>P<</i>0.001), with cats in North America losing less weight (median 7.2%, IQR: 4.4–10.4%) than those in both Europe (10.7%, 6-8-15.4%) and South America (10.0%, 6.2–15.4%). Differences in weight loss were also observed amongst countries (<i>P</i><0.001), with cats in Argentina, Germany, and Italy losing more weight than cats in the USA, and cats in Germany also losing more weight than cats in Portugal.</p><p>Discussion/conclusion</p><p>Most of the overweight cats enrolled in this international multi-centre study successfully lost weight. The reason for the differences in percentage weight loss amongst geographical locations requires further study.</p>