Research Review Corner: June 2012

Health Maintenance Care in Work-Related Low Back Pain and Its Association With Disability Recurrence

BACKGROUND INFORMATION
It is well known that low back pain (LBP) is one of society’s costliest afflictions. Aside from lost work time and treatment costs associated with a new case of LBP, a potentially significant financial burden lies in the recurrence of this condition (which, as we know, is very common).

In the occupational health field, sustained return-to-work is an important goal during injury recovery. Leaving work a second time after an initial episode is considered an appropriate indication of a recurrent condition, as this reflects the non-sustainability of working, and implies a failure of the return-to-work process.

As chiropractors, we focus more on return-to-work than perhaps any other health care providers (such as physicians, who typically focus more on pain control). In the context of the current literature, demonstrating an association between specific type(s) of treatment or provider(s) and significant recurrence of a condition (measured as recurrent work disability) could imply an important advancement in the treatment of work-related back injuries. Significant financial savings hang in the balance.

‘Health maintenance care’ is a concept familiar to most chiropractors, conceptually aimed at reducing recurrence of a particular condition (in this case LBP) and/or enhancing general health. Such care can involve a range of interventions, from providing advice to offering physical treatment or rehabilitation.

Overall, very little research has been done on the effectiveness of this approach in general, and no studies have been done on its effectiveness for work-related LBP specifically. Therefore, the aim of this study was to compare occurrence of repeated disability episodes across types of health care providers (chiropractors, physical therapists and physicians) who treat claimants with new episodes of work-related LBP. The authors hypothesized that since chiropractors generally are strong proponents of health maintenance care, their patients would experience a lower risk of recurrent disability.

Pertinent Results

·         The final study cohort was composed of 894 cases – median age was 41, 32 per cent were women.

·         The most frequent jobs held by claimants were transportation and material moving (29.1 per cent), production (12.8 per cent), office and administrative support (9.6 per cent), and building and ground cleaning (6.0 per cent).

·         During the ‘disability episode’, the largest group sought only or mostly physical therapy care (48 per cent), followed by only or mostly chiropractic (27 per cent).

·         During the health maintenance care period, the largest group was only or mostly visits to a physician (31 per cent), followed by only or mostly visits to physical therapist (24 per cent) and only or mostly visits to chiropractor (21 per cent). 16 per cent received no medical care during the health maintenance care period.

·         After controlling for demographics and severity, the hazard ratio [HR] of disability recurrence for patients of physical therapists (HR = 2.0; 95 per cent confidence interval [CI] = 1.0 to 3.9) or physicians (HR = 1.6; 95 per cent CI = 0.9 to 6.2) was higher than that of chiropractors (referent, HR = 1.0), which was similar to that of the patients non-treated after return to work (HR = 1.2; 95 per cent CI = 0.4 to 3.8).

·         In general, those who saw chiropractors utilized fewer opioids, underwent less surgery, had lower medical costs and shorter periods of initial disability than those who consulted other providers.

·         About 11per cent of the cases experienced recurrence (n = 98). Provider type during the health maintenance care period was significantly associated with recurrent disability (P = 0.0053) with the only or mostly physical therapy group having the highest proportion of recurrent disability (16.9 per cent) and the only or mostly chiropractor and the no health maintenance care groups having the lowest proportion of recurrent disability (6.5 per cent and 5.5 per cent, respectively).

·         Rough estimates for mean duration at work after the initial period of disability and before the recurrence were ~345 days for only or mostly chiropractic during health maintenance care period, ~316 each for physical therapy or physician patients…overall not a large difference among the three provider types.

Study Methods

Data was analyzed from the administrative records of a large insurance company that represents approximately10per cent of the United States workers’ compensation with coverage in many states, industries, and company sizes. Claims filed in 7 states (Illinois, Massachusetts, Maryland, New Hampshire, New York, Texas, and Wisconsin) between January 1^st and December 31^st, 2006 were reviewed because claimants in these states can choose the provider they prefer to see for a work-related injury.  11 420 non-specific LBP cases were identified by body part (lower back, sacrum, coccyx, or multiple trunk) and nature of injury (sprain or strain) codes.  All claimants were followed from the date of injury until 12 months after the first episode of disability. 

Provider ‘Type’ and Outcomes

The authors evaluated whether each health care visit was physical therapy, chiropractic or medical services to identify a primary care provider for each case.  For those patients who saw multiple practitioners, the professional that accounted for 50 per cent or more of the visits was designated as provider ‘type’.  Comparisons were then made among the three provider types for ‘time-to-disability-recurrence’. This was defined as the number of days between the first day of returning to work for at least 15 consecutive days after the initial disability episode until the day before recurrence of disability. Recurrent disability was defined as the resumption of at least 15 consecutive days of temporary total disability payments following the health maintenance care period. The authors appropriately controlled for a variety of other factors including: age, gender, job tenure, severity of LBP, and comorbidities.

Disability Definitions

Temporary total disability was defined as the worker being completely unable to work on a temporary basis due to health related impairment, was used for each claimant to determine the beginning, end, and duration of each disability episode and health maintenance care period (defined as the period after the initial disability episode had ended and the person had returned to work for more than 14 days).  Temporary partial disability periods, defined as the worker returning to work but on an alternate duty job, usually part time with lower wages, were defined as periods where the claimant was working and were included in the health maintenance care periods. Recurrent disability was defined as a resumption of temporary total disability compensation after an episode of health maintenance care.

Those claimants whose first disability episode was seven days or less were excluded from the data set (n = 755) because there is a waiting period for disability compensation of up to seven days that varies by state.  If the health maintenance care period was seven days or less, it was assumed that the person was not truly ready to be back at work, and this period was included in the initial disability episode that bounded it. Claimants with a health maintenance care period between eight and 14 days were excluded from the study cohort under the assumptions that it is not likely that the actual pattern of service utilization during this period could have been properly determined in such short time period (n = 69).

Exclusions

If claimants received no paid disability, they were excluded (n = 7552). To capture new episodes of LBP cases, the authors also excluded claimants who filed a workers’ compensation claim in the prior year (they were identified by using the same LBP identification, n = 227). To obtain as homogeneous a study population as possible, additional cases were excluded according to the following criteria:

1)     More than one injury date was reported for the same claim (19 excluded);

2)     The first disability episode began more than 7 days after the injury occurred, which ensured that all cases shared similar severity/complexity with respect to requirements for work disability within the first week after the injury (652 excluded);

3)     The claimant had fewer than four physical therapy or chiropractic visits during the disability episode period, which could have resulted in improper characterization of disability episode period treatment because of unstable numbers (1182 excluded);

4)     The claimant was < 17 or > than 65 years old (13 excluded);

5)     The first medical visit occurred more than 14 days after the injury occurred, which implies a retroactive evaluation of work causality where cases could have received some type of treatment not included in claim bills, causing misclassification of received health care (33 excluded);

6)     During first medical visit, none of the diagnoses was related to LBP were determined (18 excluded);

7)     The follow-up of the health maintenance care period was less than 1 year when censored at July 31, 2008 (73 excluded); or

8)     Incomplete data (two excluded).

Study Strengths and Weaknesses

Readers should keep the following in mind when interpreting the results of this study:

·         Maintenance care from chiropractors, although better overall than similar care from a physical therapist or physician, was roughly equivalent to receiving no maintenance care at all.  This suggests, perhaps, that one benefit of seeing a chiropractor is that patients may avoid some unnecessary treatments that may promote recurrent disability (such as drugs and surgery).

·         As mentioned, chiropractic patients generally required fewer opioids and surgery, suggesting that perhaps this group overall represented those with LBP that was less severe (the authors did attempt to control for this, but the possibility remains).  Having said that, prior literature suggests a poor association between severity of LBP and return-to-work (1).

Conclusions and Practical Applications
In this study, an analysis was conducted of 894 patients suffering work-related LBP, from their first episode of disability through their subsequent return-to-work (health maintenance care period). Overall, about one tenth of the subjects experienced recurrent disability due to LBP.

After the authors controlled for demographics and severity indicators, the likelihood of recurrent disability due to LBP for recipients of services during the health maintenance care period by all other provider groups was consistently worse when compared with recipients of health maintenance care by chiropractors. Receiving chiropractic care during both disability (“curative”) and health maintenance care periods (main exposure variable, “preventive”), and the combination of both (curative and preventive) was associated with lower disability recurrence.

This study is one of the first of its kind, offering supportive data from a work-related LBP perspective that our profession can utilize to support our continued inclusion in the care of occupational LBP. Further research is required to confirm and expand on these results, as well as extend our investigation of other common occupational injuries.

Additional References

Takahashi N, Kikuchi S, Konno S, et al. Discrepancy between disability and the severity of low back pain: demographic, psychologic, and employment related factors. Spine 2006; 31: 931–939.

Dr. Shawn Thistle is the founder and president of Research Review Service Inc., an online, subscription-based service designed to help busy practitioners to integrate current, relevant scientific evidence into their practice. Shawn graduated from CMCC and holds an Honours Degree in Kinesiology from McMaster University. He also holds a certificate in Contemporary Medical Acupuncture from McMaster University, and is a Certified Active Release Techniques (ART®) Provider. For more information about the Research Review Service, visit www.researchreviewservice.com .