Causes and prevention of long-term disability due to low back pain. An inquiry from the perspective of insurance medicine.

Background In western societies, low back pain (LBP) is one of the leading disorders resulting in long-term disability. In Belgium, disability is compensated through the Belgian Social security system where medical advisers of sickness funds play a key role in the disability evaluation of claimants. In daily practice, they are often confronted with claimants suffering from LBP and LBP surgery. Over the years, there has been a change of focus from disability evaluation to the prevention of lengthy sick leave by facilitating early and safe resumption of work. The bio-psycho-social model of illness is gaining acceptance among insurance physicians and has the potential to provide a basis for screening and intervention in the transition from acute to chronic LBP and disability. To date, scientific evidence for a rehabilitation oriented approach in the disability evaluation of LBP by medical advisers is lacking. Aims The main aim of this doctoral thesis was how the insurance physician can improve the recovery of claimants suffering from LBP and prevent prolonged disability. This objective requires a thorough understanding of the factors that influence the resumption of work following LBP to screen out claimants at risk. Given the potential role of the insurance physician as counselor, it is extremely important to evaluate whether claimant reassurance and LBP information is superior to disability evaluation alone. To gain insight into the social and economic burden of disability due to LBP in Belgium, the present dissertation first focused on lumbar spine surgery as treatment option for LBP. Methods Two different study designs were employed: cohort studies and a randomized controlled trial. The epidemiology, outcome and cost of lumbar spine surgery was investigated by a retrospective cohort study design using data obtained from records from the administrative databases from the Alliance of Christian Sickness Funds and the National Institute for Health and Disability Insurance. Risk factors of long-term disability due to LBP were examined using a prospective cohort design in claimants suffering from LBP who were filing for sickness allowances. The study employed a battery of 12 standardized questionnaires. A similar prospective design was used to develop a brief screening tool for detecting claimants at risk for lengthy disability. Using a single-blinded randomized controlled trial design, an intervention involving patient education and support to prevent long-lasting disability was assessed in comparison to standard disability evaluation. Results 1. Lumbar spine surgery Belgian spine surgery rates rose 44% from 2001 through 2009. Combined discectomy and fusion rates have increased steadily since 1989 and outpaced standard discectomy. Since 2003, there was an overall upward trend in disc replacement with a yearly increase of 17%. Duration of hospital stay following lumbar spine surgery showed a large variation between Belgian hospitals and significantly decreased throughout the last decade. There was a twofold variation in provincial rates of spine surgery. Reported 1-year mortality varied from 0,6% to 2,5% among surgical procedures performed in 2008.The overall 5-year reoperation rate was 12%. The no-Return to work (RTW) rates one year after standard discectomy, ALIF and PLIF were 14,4%, 22,7% and 26,1%, respectively. The 2003 RTW rates one year after disc replacement and combined discectomy and fusion were respectively 61,5% and 50,6%. Length of sick leave before surgery was the most important factor that correlated with poor work resumption. Older age, female gender and combined discectomy and fusion were other significant factors consistently associated with no RTW one year after surgery. Overall, type of surgery and geographic region were significantly related to patient outcomes. No significant difference between disc replacement and combined discectomy and fusion was demonstrated in terms of RTW. 2. Non-specific LBP Three months after the start of the sick leave period 47% of the LBP claimants had not resumed work. The strong predictors for sickness absence lasting more than 3 months were Oswestry disability index, fear of avoidance severity score, blue collar worker, LBP for less than 12 weeks before sick leave and pain behavior. An easily applicable screening tool comprising 3 questions related to pain below the knee, patients own prediction of RTW and interference of pain on daily activities correctly classified 73,7% of the non-resumers and 78,4% of the resumers at a cut-off score of 0,22 (c statistic = 0,801). Claimants who received information and advice showed a higher RTW rate which was statistically significant at one year of sick leave mainly due a lower relapse rate. There was no effect on subsequent surgery for LBP and duration of sick leave. Conclusion The current study on lumbar spine surgery demonstrated that the analysis of health insurance claims is a useful adjunct to surveillance of changes in spine surgery and their impacts. Regional variations in particular call for a more consistent approach to clinical care and to peer-review current practice against evidence- and consensus- based clinical guidelines. Patients eligible for spine surgery should be screened for the length of sick leave before surgery since it was the most important factor associated with outcome. Surgeons should bear in mind the non-superiority of disc replacement surgery in the short run compared with combined discectomy and fusion. A brief screening tool comprising three questions related to pain below the knee, patients own prediction of RTW and interference of pain on daily activities is a useful means of identifying LBP claimants at risk of prolonged disability. Especially patients own prediction is a potentially modifiable risk factor and may be amenableto intervention. Reassurance and education on LBP should be part of a disability evaluation to allow early and safe RTW.

Publication year:2014

Accessibility:Open