What determines outcomes? Can risk be assessed?

Pathological factors often account poorly for important questions in ORMSD, such as presentation, variations in prevalence, prognosis, disability duration, return to work, therapy selection and management . Among those factors that can be readily appreciated are initial pain and disability scores, and general health status. Factors described as psychosocial, an interacting collection of individual, group and social factors, are predictive of the longitudinal course of many illnesses, including ORMSD . Observations of the influence of such factors in medicine are not new. As Sir William Osler observed, “It is much more important to know what sort of patient has a disease than what sort of disease a patient has .”

Assessing risk factors for disease is a familiar process in clinical medicine. Risk factor screening for serious medical conditions is readily achieved for musculoskeletal conditions – by the application of the so called ‘red flags’ , though specificity is lacking. ‘Yellow flags’ are posited as important psychosocial, non-biomedical risk factors that may require specific intervention. In acute LBP, subgroups of patients can be readily identified depending on whether disability is related to pain beliefs, emotional distress or workplace concerns . Psychosocial risk factors may influence the journey from injury to chronic disability . Factors can be seen as phasic in action, acting before injury or early in injury (acute and sub-acute) or in persisting work disability .

The work environment has a number of important factors that contribute to physical and psychosocial risk factors . Physical factors at the workplace, such as ergonomic load, manual handling and the physical work environment, have an influence on the incidence on ORMSD and also act as a barrier to return to work in the presence of activity limitation. Work organisation factors such as supervisory support, high demand and low control (derived from the work stress model) and high perceived workload are similarly associated with increased risk for ORMSD and lower success of rehabilitation . In a study of Boeing aircraft workers, job dissatisfaction and distress appeared the most significant . However, such findings may not generalise from LBP to other conditions .

One tool developed for clinical use to identify early those at risk for long-term disability is the Orebro Musculoskeletal Questionnaire. At 6 months’ follow-up after initial administration, scores above a cut-off exhibited a sensitivity of 89%, a specificity of 65% for prolonged absenteeism, and a sensitivity of 74% and a specificity of 79% for functional ability.

Mood disorders, particularly major depressive disorder, appear to be underdiagnosed in the early stages of work-related injury . At the end of the anxiety spectrum, panic disorder or post-traumatic stress disorder (PTSD) can occur following exposure to high levels of real or perceived danger, especially when injury occurs . PTSD and chronic pain are intimately associated, sharing certain common central mechanisms . Chronic, untreated PTSD can run a protracted course with severe psychiatric and physical morbidity, and must be recognised as an important obstacle to recovery following some types of ORMSD .

Screening for mood disorders can be as straightforward as asking an individual two simple questions: “Over the past month, have you felt down, depressed, or hopeless?” and “Over the past month, have you felt little interest or pleasure in doing things?” Respondents need more in-depth screening and clinical assessment . Anxiety disorders are not as easily screened and the use of a validated instrument is useful. A number of validated questionnaires with high sensitivity and specificity are available. These are frequently combined with scales examining other aspects of affective disturbance, and can be completed by a patient in the waiting room .

A potential contributor to the complexity of managing ORMSD is the experience of anger and perceived injustice regarding the circumstances of injury, claim adjudication and rehabilitation . Turk and colleagues identified high levels of anger in a population of chronic pain patients, whilst Kerns and colleagues were able to demonstrate strong associations between anger, affective disturbance and self-rated disability. The presence of depression and anger appears to have a negative effect on the relationship between injured workers and treatment providers . Over 60% of chronic pain patients in one study harboured high levels of anger towards their doctors . Bruns and colleagues identified chronic pain, litigation and affective dysregulation as the strongest predictors of homicidal ideation towards doctors .

Biopsychosocial risk factor screening is a useful tool for rehabilitation and injury management, and should be differentiated from conceptualisations of work disability derived from ‘organic’ versus psychiatric models or motivational/malingering constructs. In 1980, Waddell, an orthopaedic spinal surgeon, described a series of signs observed during examination of the lumbar spine and posited that these occurred independently of pathoanatomical processes . Main described the growing misuse of these signs . Fishbain and colleagues subsequently published a detailed review of studies describing the use of Waddell signs . This analysis of 57 published studies confirmed that Waddell signs were associated with poorer treatment outcomes. They were not able to demonstrate that Waddell signs were associated with ‘non-organic’ factors, secondary gain, malingering or a proxy for a psychological disorder .