Work Disability After Whiplash: A Prospective Cohort Study
From: Spine. 2009 Jan 14. [Epub ahead of print]
To investigate the consequences of neck pain after motor vehicle accidents in terms of disability for work and the relationship this has with symptom and work-related factors. Previous studies on work disability related to whiplash are very heterogeneous, are often limited in sample size and show a wide variability in terms of results. A relationship has been suggested between poor recovery from or persistent work disability after whiplash and female gender, older age, marital status, heavy manual work, self-employment, prior psychological problems, subjective complaints of poor concentration, pain catastrophizing, and kinesiophobia.
Individuals with neck complaints after involvement in traffic accidents, who initiated compensation claim procedures with a Dutch insurance company (n = 879), were sent questionnaires (Q1) concerning the accident, the injuries that they had sustained, their complaints at that time, and questions regarding work and disability. The course of complaints and work disability was monitored at 6 (Q2) and 12 months (Q3) after the accident. A total of 58.8% of the population with neck complaints studied was work-disabled after the accident. Age and impaired concentration complaints after 1 month were found to be related to work disability at 1 year, independent of physical complaints and work characteristics.
The results show that work disability due to postwhiplash syndrome after a motor vehicle accident is a common problem. A total of 58.8% of the studied population with neck complaints was work-disabled after the accident. However, the vast majority of this group recovered from work disability in the first year: 31.3% in the first month, 66.7% in the first 6 months, and 78.3% in the first year, leaving 21.7% participants with persistent work disability after 1 year (12.6% of the individuals with initial neck complaints), which is in line with the reported 12% return from work disability in the first year reported in a previous research. However, it is much lower than the 44% reported, most probably because of population differences
The univariate analysis shows several factors, especially those related to physical complaints, to be related to concurrent work disability. Even more relevant, the multiple regression models reveal that in the first month, physical factors such as higher neck pain intensity, more restricted neck movements, and use of medication, are independently related to work disability, together with impaired concentration. At 6 months, concurrent higher neck pain intensity and more concentration complaints were found to be related to persistent work disability. In line with previous
research, concentration complaints were found to be related to concurrent work disability at 12 months.
Although one might expect disability for white collar work to be more affected by concentration problems, our results surprisingly show that prolonged work disability is related to concentration complaints independent of the degree of manual labor (blue or white collar work) or level of education. Apparently, concentration complaints affect the ability to work regardless of the level of manual labor or level of education. In contrast with previous research, we found neither self-employment nor gender to be a significant predictive factor related to work disability.
Regarding the analysis of the predictive value of parameters, age and impaired concentration complaints were found to be the only factors available at 1 month that were related to work disability at 1 year, independent of physical complaints and work characteristics. The intensity of concentration complaints could be an indication of depressive or anxiety symptoms. It would, therefore, be important for future research to investigate whether anxiety or depressive symptoms are indeed related to persistent work disability. The current results suggest that work disability could benefit most from interventions related to recovery from cognitive complaints and less from physically related interventions.
Although the relevance of age in regard to functional recovery from postwhiplash syndrome is a subject of discussion, the results clearly sustain the view that prolonged work disability is most pronounced in higher age groups.
Interestingly, previous research consistently found early neck pain intensity to be a main factor related to recovery after 1 year. These results indicate that this is not the case for work disability, indicating that the prediction of functional outcome parameters, although being more relevant in regard to overall costs, cannot readily be deduced from research on complaint-related recovery.
Age and concentration complaints were important independent predictors of long-lasting work disability, whereas no evidence emerged to indicate that the degree of manual labor (blue or white collar work) or educational level was involved in persistent work disability in postwhiplash syndrome. The current results suggest that work disability could benefit most from interventions related to recovery from cognitive complaints and less from physically related interventions.
