Veterinary-care events and costs over a 5-year follow-up period for warmblooded riding horses with or without previously recorded locomotor problems in Sweden

Our objective was to determine the amount, type and cost of veterinary care during a 5-year follow-up period, in Swedish warmblooded riding horses with and without locomotor problems as recorded in 1997. The study population comprised horses with complete insurance both for veterinary care and life during 1997. The horses were followed from the beginning of January 1998 to the end of December 2002. The exposed cohort was composed of 1558 horses that had experienced >or=1 veterinary-care event because of locomotor problems in 1997 (LP-cohort). The exposure-negative (LN) cohort was composed of 16,513 horses that had no recorded locomotor problem during 1997. For the outcome of locomotor problems during the follow-up period, stratified incidence proportions and a repeated-measures multivariable-logistic regression model in general produced the same conclusions. An interaction between year and cohort showed larger odds ratios (ORs) in the first year of follow-up compared to later (OR 4.8 and 1.2 in the LP- and LN-cohort, respectively), but a smaller difference during the subsequent years (in the 5th year OR 1.8 and 1.0, respectively). Horses with life-insurance values of >30,000 SEK in the LP- and LN-cohorts had ORs of 4.7 (99% CI 3.9, 5.6) and 2.6 (99% CI 2.3, 2.9), respectively. For life-insurance values of