Evidence-based predictors of return-to-work in LBP patients

Low-back pain is a leading cause of work absenteeism in Canada and other industrialized countries. Most workers with acute low-back pain (those experiencing pain for up to six weeks) return to work following a relatively straightforward path. Unfortunately, some do not.

Studies show that anywhere between one in five to one in three workers with acute low-back pain develop chronic pain (defined as pain lasting longer than three months). Lengthy disability absences result in workplace disruptions and productivity losses to employers, and high compensation and treatment costs to workers’ compensation and public health systems.

More importantly, lengthy delays also have detrimental consequences for the injured worker. According to research conducted by the Institute for Work & Health (IWH) or with IWH involvement, depressive symptoms are more common among workers who are not back at work at 12 months. Workers permanently impaired by a job injury experience a greater risk of depression, sleep problems and medication abuse than the general population. They may also be at greater risk of early mortality.

It’s important for chiropractors to understand the factors that affect the length of time it takes before low-back pain patients return to work. In a past IWH focus group study, many chiropractors said their role includes providing education, reassurance and encouragement to patients to remain active, in addition to using manipulation to control pain.

“We are primary care providers, and injured workers with low-back pain will sometimes seek out our care before they go to their family physicians,” says Dr. Peter S. Y. Kim, a fellow of the College of Chiropractic Sciences and an associate professor at the Canadian Memorial Chiropractic College. He is also a member of IWH’s Educationally Influential Chiropractor Network. “As a result, chiropractors have a responsibility to use the up-to-date information that’s available to them to help manage the condition before it becomes chronic.”

What the evidence says
As chiropractors treat injured workers with low-back pain, they are sometimes asked about prognosis for recovery and expected amount of time before the workers can return to full work. Research conducted at the IWH has produced a systematic review that may help practitioners make the determination.

According to the systematic review, led by Dr. Ivan Steenstra, then associate scientist at the Institute, strong evidence suggested these following factors influence return to work among those with acute low-back pain:

• recovery expectations;
• workers’ interactions with health-care providers (i.e., type of health-care provider seen and nature of care received);
• workers’ self-reported pain and functional limitations;
• presence of radiating pain (an indication of the severity of the injury); and
• work-related factors, which include physical demands of the job, job satisfaction and the offer of modified work.

The research team also found strong evidence that the following factors do not influence return-to-work (RTW) among those with acute low-back pain:

• lifestyle (e.g. smoking, drinking);
• pain catastrophizing (e.g. an individual’s description of pain as awful, horrible and unbearable); and
• level of education.

There was moderate evidence that the following factors influence RTW among those with acute low-back pain:

• workplace psychosocial environment (i.e. factors related to work pace, control and social support);
• claim-related issues (i.e. type, timeliness and perceived fairness of claims for disability benefits);
• job tenure;
• prior claim or injury; and
• treatment-related issues (e.g. health-care provider response to patient pain).

There was moderate evidence that the following factors do not influence RTW among those with acute low-back pain:

• findings from clinical examinations; and
• depression.

In an IWH systematic review, “strong evidence” means consistent findings came from more than one high quality study. Findings that are consistent across multiple medium-quality studies, or from at least one high-quality study and at least one medium-quality study, are considered “moderate evidence.” Findings that are not consistent, or that come from low-quality studies, are reported as “insufficient evidence.”

In sum, workers’ recovery expectations are the strongest predictor of return to work. As supported by many high-quality studies, those who expect to recover and return to work more quickly, do so. Therefore, a simple question asking about recovery expectations during the screening or assessment of workers in the early stages of acute low-back pain could help identify those at high risk of long work absences and, consequently, in need of extra attention to help them recover and return to work more quickly.

The next factor supported by strong evidence is the nature of the treatment or care workers receive for their acute low-back pain. The type of health-care provider and the type of care provided matter. For example, some studies show that seeking care from a chiropractor results in shorter time on disability.

There is strong evidence to show workers’ reports about their pain intensity and functional limitations are predictive of return to work: the greater the self-reported pain and physical limitations, the slower the return to work. Since both can be easily measured in several ways with well-validated questionnaires, they should be included in assessments to determine those at high risk of long-duration absences.

There is strong evidence to show that the presence of radiating pain is associated with longer periods off work. However, radiating pain – often used as a measure of injury severity – is usually considered to be a “red flag” during clinical assessments, an indication of potential neurological problems that warrant further medical investigation. For that reason, some people view this more as a screening factor for more specific, less-benign low-back pain.

A few work-related factors are supported by strong evidence as being predictive of return to work. Physical job demands, as determined by occupation, is one of them. That is, workers with acute low-back pain who work in more physically demanding jobs, such as construction or manufacturing, are slower to return to work.

Job satisfaction is another work-related factor shown to be predictive of RTW: the higher the satisfaction, the more likely the return. Although job satisfaction is probably related to any number of factors at work, a simple question asking about job satisfaction can be used at the very start of a work disability process to identify those at high risk and in need of extra attention.

The offer or availability of modified duties or workplace accommodations is another work factor associated with improved RTW outcomes. Interestingly, it seems the offer of modified work, not its actual implementation, predicts the likelihood of return to work.

The evidence did not point to depression as a factor affecting RTW following acute low-back pain. Neither did it point to pain catastrophizing. It could be that both are not predictive of return to work until back pain becomes chronic.

The research evidence to date shows certain factors can be used to identify workers with acute low-back pain who are at high risk of poor outcomes. The factors identified in this review – such as recovery expectations, interactions with health-care providers, self-reported pain and physical limitations, and physical demands of the job – could be used to screen those workers at high risk of long-term or permanent disability.

“In the past, we were taught that smoking and drinking may be risk factors for slower recovery and thus possible contributors for developing chronic pain. Current research indicates that they have not been demonstrated to be associated with RTW factors,” says Kim, who has been a practicing chiropractor for the last 25 years. “So I think it’s important that anyone who’s treating individuals with low-back pain look at the current, evidence-based, peer-reviewed research that’s available on the predictors and address them.”

More information about the systematic review on the factors affecting return to work following acute low-back pain can be found at: http://www.iwh.on.ca/sbe/factors-affecting-rtw-following-acute-low-back-pain. Work is ongoing to turn this research into a guide for physicians.

To sign up for news and updates about this guide and other IWH research, tools and projects, please go to www.iwh.on.ca/e-alerts.

Screening Tool
The ability of individuals to recover from low-back pain and return to work is influenced by psychological issues and their interaction with social factors. It sometimes helps to have a tool to screen for these “psychosocial issues” – especially a tool that can indicate what the specific problems are and the types of targeted interventions needed to help them recover and return to work sooner.

Dr. Ivan Steenstra, IWH associate scientist at the time and lead author of the systematic review on factors affecting return to work following acute low-back pain, was more recently part of a team that developed a psychosocial screening tool to estimate the likelihood that workers with acute low-back pain can quickly recover and return to work within three months after an injury.

This tool, a questionnaire of 46 items, called the Pain Recovery Inventory of Concerns and Expectations (PRICE) also groups workers into four risk categories, allowing clinicians to target interventions. Research shows it’s a valid and reliable tool for identifying what intervention programs may help them most.

The research examined the four groupings of patients: those at minimal risk, those with emotional distress (e.g. for depressive symptoms, pain intensity, pain catastrophizing, activity avoidance, functional limitations and life impact of pain), those with activity limitations, and those with organizational concerns. It found among the four risk subgroups, those scoring high for emotional distress were seven times less likely than those in the low-risk group to be back at work within three months. Those in the other two subgroups – high physical limitations and workplace concerns – stood only a slightly higher chance than those in the low-risk group of not being back at work.

“This tool looks at low-back pain patients as different subgroups, which most other prognostic studies tend not to do,” Steenstra says. “Using this approach, we find certain factors may be important for certain subgroups, but not for all. That may be why pain catastrophizing appears to be an important factor with this tool but not in the IWH systematic review.”

As a result of these findings, Steenstra says, clinicians can target interventions needed to help prevent long-term disability. For example, for patients lacking organizational support, interventions might include participatory ergonomics interventions, facilitated communication with supervisors or problem-solving to address workplace barriers. For patients with severe emotional distress, interventions might include group or individual sessions applying cognitive-behavioural strategies to address unhelpful pain beliefs, strengthen coping skills and learn pain self-management. For patients with severe pain and activity limitations but without emotional distress, interventions might focus on pain education, graded exercise and exposure to gradual activity.

Uyen Vu is communications associate and editor of the Institute for Work & Health’s quarterly newsletter, At Work. The Institute for Work & Health is a not-for-profit, independent research organization focusing on work-related injury and disability prevention.