Healthcare consultation and sick leave before and after neck injury: a cohort study with matched population-based references

OBJECTIVES Recent studies based on self-assessed data on exposure and outcome suggest a negative association between poor health before neck injury and recovery. Our aim was to study actual healthcare consultation and work disability before and after neck injury (whiplash). DESIGN Cohort study with matched references studied prospectively and retrospectively via regional and national held registers. SETTING Population-based study in Region Skåne, Sweden (population=1.21 million) including all levels of healthcare. PARTICIPANTS 1443 participants aged ≥18 (54% women) with acute neck injury, Whiplash, (International Classification of Diseases-10-SE code S13.4*) in 2007 or 2008 and no such diagnosis since 1998. Each patient with a neck injury was assigned four randomly selected population references matched for age, sex and area of residence (97% of the patients and 94% of the references were followed during the whole study period). PRIMARY AND SECONDARY OUTCOME MEASURES We studied changes in healthcare consultations 3 years before to 3 years after diagnosis as well as sick leave episodes. Analyses were also stratified by preinjury frequency of consultation. RESULTS Before the injury, the mean number of total consultations over 36 months among the neck injured (n=1443) and references (n=5772) was 9.3 vs 7.2 (p<0.0001) and postneck injury 12.7 vs 7.8 (p<0.0001). In the group of high-frequent consulters, there were more women compared with frequent and low-frequent consulters (70.6% vs 32.8%; p<0.0001). Among low-frequent and frequent consulters preinjury (n=967, 67% of the cohort), 16% became high-frequent consulters attributable to the injury. The number of days of sick leave preinjury was correlated with the number of preinjury and postinjury consultations (r=0.47 (99% CI 0.38 to 0.49), r=0.32 (99% CI 0.25 to 0.37)). CONCLUSIONS People with a neck injury constitute a heterogeneous group. The preinjury level of healthcare consultation is associated with the postinjury level of consultation.