Nationwide Utilization of Computerized Dynamic Posturography in an Era of Deimplementation

Abstract

Computerized dynamic posturography (CDP) provides multisensory assessment of balance. Consensus is lacking regarding CDP utility and coverage determinations vary. To inform best practices and policy, this cross-sectional study quantifies provider use of CDP among Medicare beneficiaries over time (2012–2017), by geographic region (hospital referral region [HRR]), and specialty. We observed 195,267 beneficiaries underwent 212,847 CDP tests totaling $15,780,001 in payments. Number of CDPs billed per 100,000 beneficiaries varied 534-fold across HRRs. Over 6 years, CDP use grew by 84% despite stagnant reimbursement. More utilization was attributable to primary care clinicians than specialties focused on care for dizziness and balance disorders. The observed growth and variation illustrate the potential for policy and provider preferences to drive unexpected practice patterns and underscore the need to engage a broad network of providers to develop optimal guidelines for use. CDP may offer a use case for deimplementation of low-value diagnostic services.

Computerized dynamic posturography (CDP) is a test that utilizes costly equipment to provide a quantitative multisensory assessment of balance.¹ While the American Academy of Otolaryngology–Head and Neck Surgery recognizes CDP as medically indicated for dizziness and balance disorders,² consensus is lacking regarding its utility. CDP is not uniformly covered by US commercial insurers who justify exclusion based on weak evidence of benefit on patient-relevant outcomes.³ For example, CDP results correlate poorly with other vestibular tests, yielding only 50% sensitivity on meta-analysis for detecting confirmed vestibulopathies.^1,4,5

A cornerstone of US healthcare policy is the deimplementation of low-value services that provide little benefit, cause harm, or inflict unnecessary costs.⁶ We aimed to quantify CDP utilization, by geographic region, and provider specialty to inform efforts to optimize health services for dizziness. Medicare provides local coverage determinations for CDP thus supplying a population in which to examine utilization within the United States.

Methods

CDP Sensory Organization Test utilization (CPT 92548) for individual providers was extracted from the 2012 to 2017 Medicare Provider Utilization and Payment Data Physician and Other Supplier Public Use File and linked to the Dartmouth Atlas to map providers to 306 healthcare referral regions (HRRs).^7,8 Annual CDP utilization intensity quartiles were determined and providers were categorized into specialty groups, as previously described.^7,8 University of Minnesota Institutional Review Board exemption was obtained.

Results

Between 2012 and 2017, 212,847 CDP tests were performed on 195,267 Medicare beneficiaries totaling $15,780,001 payments. Utilization increased 83%, from 63 per 100,000 in 2012 to 115 per 100,000 in 2017. Primary care provider (PCP) use grew 234% and was responsible for 66% of the growth in CDP use overall (Figure 1). In 2017 the greatest proportion of CDP use was by PCPs (43.5%) and neurologists (21.7%), followed by otolaryngologists (10.7%) and audiologists (10.5%). In 2017, CDP used varied 534-fold across HRRs (range: 5.3-2849.0, interquartile range: 210.1, extremal ratio: 533.6) (Figure 2). Median Medicare reimbursement for CDP was $75.85 (range: $61.27-$91.38) and was stable during the study period with a median rate of $77.37 in 2012 and $72.07 in 2017.

Figure 1.

Computerized dynamic posturography (CDP) utilization per 100,000 Medicare beneficiaries by provider type.

Figure 2.

Utilization intensity of computerized dynamic posturography (CDP) across US healthcare referral regions (HRR). Utilization intensity is tests per 100,000 beneficiaries. HRRs in white indicate regions where no clinician billed Medicare for >10 procedures.

Discussion

We observed marked geographic and provider-level variation in nationwide CDP use. Despite stagnant reimbursement, CDP use increased 83% over a 6-year period. PCPs were responsible for the greatest proportion of use and growth.

As dizziness and balance disorder prevalence among Medicare beneficiaries is similar across regions,⁹ geographic variations in CDP use likely reflects clinician practice patterns and resource supply more than medical need.¹⁰ Guidelines directing clinical application of CDP are lacking,¹¹ leaving ample room for care variations based on clinician beliefs, training, and incentives.¹² CDP equipment is also costly, contributing to supply limitations and the adaptation of less expensive videogame consoles for posturography. While such systems have good correlation with commercial CDP systems,¹³ they do not replicate traditional CDP protocols. Claims captured in this study are expected to include tests performed with CDP systems of varying quality. Some Medicare administrators have required CDP claims to include system serial numbers to prevent fraud.¹⁴

Rather than being diagnostic or lesion-localizing, CDP measures ability to incorporate vestibular, visual, and proprioceptive inputs to assess the functional status or vestibular compensation,¹⁵ inform vestibular rehabilitation,¹⁶ and identify aphysiologic behaviors (e.g., medicolegal cases).^17,18 These decisions are commonly made by otolaryngologists, neurologists, physical therapists, and audiologists; however, we observed PCPs obtained more CDPs than those specialties combined. We hypothesize that PCP practices are driven by falls risk assessment (FRA), an alternative proposed CDP indication. CDP has been investigated for FRA although most studies use less intensive protocols than standard CDP.^19–23 Recent reports provided no consensus regarding accuracy or cost-effectiveness of CDP for FRA but showed other tests, including the Timed Up-and-Go, are more accurate and less expensive.^19–22

Despite low-quality evidence, providers may be incentivized to use CDP for FRA by Medicare initiatives. FRA is a required element of Welcome to Medicare and Annual Wellness visits.²⁴ Use of CDP satisfies this requirement and increases reimbursement compared to other FRA methods, as it is not subject to Multiple Procedure Payment Reduction, a policy that implements a 50% payment reduction to the practice expense value of the second and each subsequent code billed on the same date.²⁵ CDP use may also be incentivized by the Merit-Based Incentive Payment System (MIPS), which ties Medicare reimbursement to scores on multiple quality measures. MIPS has received significant criticism, notably by the American College of Physicians, which found 37% of the quality measures were not clinically valid.²⁶ Use of CDP marks a visit as satisfying multiple measures, including Quality Measure #318, “Falls: Screening for Future Fall Risk,” a measure that the ACP specifically warned “could promote overuse of low-value services.”^27–29

This Medicare claims-based study may have limited generalizability to practices with younger, commercially insured populations. The dataset does not include patient presentations or appropriateness of test indications, interpretation, or application of results.⁸ Claims were aggregated to rendering providers and the dataset was limited in its ability to differentiate or identify expected overlap between ordering and performing providers of vestibular diagnostics.

Conclusion

While CDP may provide beneficial information for specialized care of the balance disorder patient, the observed variation illustrates the potential for policy and provider preferences to drive unexpected practice patterns. CPD represents a use case for design of deimplementation strategies for low-value diagnostic services. The overarching benefits of deimplementation strategies are potentially far-reaching by increasing the velocity of quality improvement from the bedside into practice and are essential to developing optimal guidelines for dizziness and fall risk assessment.