Use of Physical Therapy for Low Back Pain by Medicaid Enrollees

Discussion

In this study, we examined physical therapy use by Medicaid enrollees with a new LBP consultation and examined health care costs and use in the following year. As anticipated, the sample had high rates of comorbid health conditions, with proportions of smoking, obesity, chronic pain, and mental health conditions much higher than regional averages.^14,15 Health care use patterns also differed from those observed for adults with LBP and private insurance, most notably, increased use of the ED.¹⁴ The setting in which the patient entered health care was associated with physical therapy use and health care use and cost outcomes. Although only a small number of patients entered care in physical therapy, this pattern was associated with lower 1-year health care costs.

Physical therapy use patterns in the study sample were similar to those in studies involving different payer mixes. In our sample, physical therapy use across the 1-year time frame was 20%, whereas annual rates of 13% to 34% have been reported for Medicare and private-payer samples.^16–18 In the present study, 164 patients (7.1%) received physical therapy within 14 days of beginning care, a rate higher than the 3.4% and 6.6% rates reported within similar time frames (14–28 days) for private payers and Medicare, respectively.^15,18 A small number of patients (3.3% of the overall sample) entered care in physical therapy. Utah permits direct access to physical therapy, and there are no restrictions on this pattern within state Medicaid policy. This small group tended to be younger, healthier, and more likely to be women than the overall sample, but the factors motivating the decision to enter health care for LBP with a physical therapist cannot be determined. It is possible that these patients had prior experience with physical therapy, a desire to manage their LBP with a more active, exercise-focused approach, or both. Considering the relevance of the choice of entry setting to outcomes and costs in the study sample, further research exploring reasons for patients' choices could lead to strategies to promote more effective and less costly options, such as physical therapy, instead of relying on the ED for entry.

A primary challenge in providing care to Medicaid recipients is the high rate of complex, comorbid health conditions.⁶ In the study sample, 41% had 2 or more comorbid health conditions, 33% had chronic pain diagnoses, and 62% had at least 1 mental health comorbidity, along with rates of smoking, substance abuse, and obesity that were higher than regional norms. With the exception of substance abuse, these comorbidities were prevalent among patients receiving physical therapy. These factors, particularly mental health conditions and the psychological factors that often accompany chronic pain, can negatively influence outcomes for LBP treatment and increase costs.^19–21 The need for physical therapists to provide effective treatment for patients with co-occurring musculoskeletal pain and mental health conditions has been discussed.^22–24 Evidence to clarify the most effective practices for patients with complex medical conditions is critical if physical therapists are to play a more prominent role in the treatment of patients who have LBP and are insured by Medicaid.

Actual and anticipated growth of Medicaid has increased attention on managing costs while providing quality care. Identifying factors placing patients at risk for high costs is an important precursor to successful cost management strategies.²⁵ Back pain is a very costly condition among Medicaid recipients,⁸ and understanding the factors related to incurring high costs therefore may be helpful. Not surprisingly, we found mental health disorders, chronic pain, smoking, and obesity to be important factors associated with LBP-related costs and the use of low-value procedures, such as imaging or ED use, for LBP. These factors are known to drive overall health care costs among Medicaid recipients.^25,26 Multidisciplinary programs that concurrently manage mental health or other risk factors (eg, smoking, obesity) along with conditions such as LBP have been advocated as being particularly necessary for Medicaid enrollees, given the high rates of co-occurring chronic health conditions,²⁷ but are challenging to implement.

We additionally found that patients' choice of setting in which to enter health care for LBP was associated with future health care use and LBP-related costs. Relative to entering care with a primary care provider, entering care with a physical medicine physician was more likely to involve imaging or injections; entering care in the ED was associated with higher LBP-related costs in the following year, and patients entering care in the ED were more likely to receive imaging or return to the ED. Conversely, patients entering care in physical therapy had lower LBP-related costs in the following year.

Strategies that influence care choices made by patients—specifically, increasing the numbers choosing to enter care with a physical therapist and avoid the ED—may help to contain costs among Medicaid enrollees with LBP. Use of the ED for nonemergency conditions, such as LBP, is a common concern for Medicaid programs.²⁸ Our results reflect this concern, as patients who began care in the ED and not with a provider office visit had higher health care costs for LBP over the following year. In the present study, 17.6% of Medicaid enrollees with LBP initially sought care in the ED, and 15.2% went within a year.

In our prior work with people who had LBP and private insurance in the same region, about 2% visited the ED for LBP across a 1-year period.¹⁴ Our results indicated that beginning care in physical therapy was a preferred option with respect to lower LBP-related health care costs. Patients entering care in physical therapy rather than the ED had LBP-related health care costs that were approximately $550 lower over the following year. As noted previously, our sample included a small number of patients beginning care in physical therapy; however, developing strategies to increase the number of Medicaid participants choosing this option for LBP has the potential to generate large cost savings.

Changing care-seeking patterns requires consideration of both system- and patient-level factors. At the system level, Medicaid enrollees more frequently move between insurance coverages or have periods of noncoverage that can break the continuity of care and influence care seeking.²⁹ Low reimbursement rates for providers and administrative burdens can create access difficulties.³⁰ Patient-level considerations may include work schedules, access to transportation, difficulty managing comorbid psychological conditions, or patterns of learned behavior.³¹ Improving LBP care patterns for Medicaid recipients requires strategies addressing both system- and patient-level factors that drive ineffective and costly patterns. Such strategies may include shifting hours of operation, educating patients and providers, and increasing the focus within physical therapy on providing self-management strategies for recurrent episodes and exacerbations. Knowledge of barriers and facilitators is required from all stakeholders (policy makers, health care systems, state Medicaid programs, providers, and patients) for the success of strategies to promote more effective, less costly care patterns.

The results of the present study should be considered in light of several limitations. First, the use of claims data precludes the collection of potentially important variables, such as pain severity and duration of symptoms. It is possible that patients who self-selected to attend or enter care in physical therapy had less complicated LBP, possibly confounding the analyses performed. We relied on ICD-9 codes to identify LBP episodes and comorbidities. The accuracy and completeness of ICD-9 coding may be questionable. We used a 90-day period of no LBP claims to define a new consultation. It is likely that some patients were dealing with chronic, recurrent LBP episodes. Finally, we did not have access to patient-centered outcomes, such as pain or function.

Although there is wide variability among states in eligibility criteria for Medicaid, coverage of physical therapy, reimbursement policies, and patient cost sharing,^32,33 the projected growth of Medicaid—particularly for adults who are not disabled—makes it likely that physical therapists will see an increased representation of Medicaid in their payer mix.¹⁷ This growth will present a variety of opportunities and challenges for physical therapy. The results of the present study examining physical therapy use among Medicaid recipients in one state revealed that physical therapy was used for LBP at rates similar to those for private insurance. High comorbidity levels were evident among patients and were associated with physical therapy use. Few patients entered care in physical therapy, but this pattern was associated with lower 1-year LBP-related health care costs.