Back Pain Registries
In the U.S., many spine-related registries are device- or procedure-focused and hence recruit patients primarily from specialists. Outside the U.S., several prospective spine registries/cohorts have been established to study various aspects of back pain and while somewhat broader in scope, most still have a specialist focus.[48–50] In contrast, Costa and colleagues established an inception cohort of 973 primary care patients with acute (less than two weeks) low back pain, demonstrating both the feasibility and value of such an approach. Identifying patients early in the course allowed measurement of baseline factors that predicted progression and chronicity.
The Back Complaints in the Elders (BACE) consortium is an international group of investigators who have independently established prospective cohorts in a primary care setting to investigate back pain among seniors. Investigators from the Netherlands, Australia and Brazil are collaborating to identify prognostic indicators leading to the transition from acute to chronic back pain in the elderly. The objectives of BOLD parallel those of BACE and similar study structures facilitate international comparisons.
Strengths of Registries
A great advantage of registries is that patient enrollment is easier than intervention trials, so large sample sizes are feasible. This increases generalizability and the ability to detect rare events, such as complications.
Limitations of Registries
Roovers highlighted the limitations of registries, including lack of proper control groups, confounding, bias, poor data quality control, and potential conflicts of interest due to industry sponsorship. Due to these limitations, registries will never replace randomized controlled trials (RCTs). The most important limitation of registries in general is the lack of a pre-defined control group. However, we can identify important subgroups contained within the registry to use for comparative effectiveness evaluations, such as patients with and without early imaging, and use propensity-matched controls to minimize selection bias associated with treatment or diagnostic testing.
Another limitation of registries is selection bias associated with enrollment. Physicians might be more likely to enroll uncomplicated patients who are likely to have better outcomes. We avoid this shortcoming by using the health information systems to identify potential patients and have a research coordinator contact and enroll them (without prior screening by the primary care physician). Limiting enrollment to integrated health systems somewhat limits generalizability, since the delivery of care within these systems is distinct from the fee-for-service delivery system, with unique incentives. Nevertheless, we believe that the advantages of integrated health systems (comprehensive tracking of healthcare utilization and well-defined population) far outweigh the limitations.
Diagnostic Imaging and Back Pain in the Elderly
Patients and clinicians both tend to under-appreciate the disadvantages of diagnostic testing. The degree of potential controversy associated with this issue was recently emphasized by the release of the U.S. Preventative Health Services Task Force report on mammography. The panel recommended against screening women in the 40–49 year old age group due to the high rate of false positives that could lead to unnecessary further testing and invasive procedures resulting in morbidity without benefit. In addition, these false positives could lead to anxiety and poorer health-related quality of life. Spine imaging in the elderly has similar problems. The rate of incidental findings is high, as high as 90% for some findings. These findings can lead to adverse labeling as well as increased unnecessary interventions, with associated morbidity. Most guidelines exclude patients older than 50 or 65 years from imaging constraints because of the increased prevalence of serious conditions in the elderly. However, it is in the elderly that the rate of incidental lumbar imaging findings is highest. One of our goals is to examine the consequences of early imaging in the elderly by comparing elderly patients who receive early imaging to those who do not.
The BOLD registry establishes an infrastructure for studying back pain in the elderly and performing future comparative effectiveness and cost-effectiveness evaluations. Strengths include accessing patients from a community-based setting and using integrated health plans to facilitate the tracking of resource use. Since the aims and design parallel studies by an international consortium of investigators, comparison with cohorts from the Netherlands, Australia and Brazil will be possible. Even without the potential for future collaborations with international collaborators, the BOLD registry is a valuable new resource for comparative effectiveness research in the United States.
JGJ, BAC, ALA, BWB, RAD, JLF, PH, LK, SSN, DRN, SDS and JAT developed the original concept of the study and developed the design of BOLD Registry study. ZB and KJ participated in the design of as BOLD and are coordinators. All authors have read and approved the final version of the article.
The study is supported by the Agency for Healthcare Research and Quality : (AHRQ) R01 HS019222.
BMC Musculoskelet Disord. 2012;13(64) © 2012 BioMed Central, Ltd.
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