Use of Chiropractic Spinal Manipulation in Older Adults Is Strongly Correlated With Supply

Abstract

Study Design Retrospective cross-sectional analysis of administrative data. Objective To examine the relationship between regional chiropractic supply and both use and utilization intensity of chiropractic services among Medicare beneficiaries. Summary of Background Data Numerous studies have documented trends and patterns in the utilization of chiropractic services in the United States, but little is known about geographic variation in the relationship between chiropractic supply and utilization. Methods We analyzed Medicare claims data for services provided by chiropractic physicians in 2008. We aggregated the data to the hospital referral region level and employed small area analysis techniques to generate descriptive statistics. We mapped geographic variations in chiropractic supply, use and utilization intensity (treatments per user) and quantified the variation by coefficient of variation and extremal ratio. We employed Spearman’s rank correlation coefficient to correlate use with supply. We employed a logistic regression model for chiropractic use and a multiple linear regression model for chiropractic utilization intensity. Results The average regional supply of chiropractic physicians was 21.5 per 100,000 adult capita. The average percentage of beneficiaries who used chiropractic was approximately 7.6 (SD 3.9). The average utilization intensity was 10.6 (SD 1.8). Regional chiropractic supply varied more than 14 fold, and chiropractic use varied more than 17 fold. Chiropractic supply and use were positively correlated (Spearman’s rho 0.68; p<.001). A low back or cervical spine problem was strongly associated with chiropractic use (OR 21.6 and 14.3, respectively). Increased chiropractic supply was associated with increased chiropractic use (OR 1.04), but not with increased chiropractic utilization intensity. Conclusion Both the supply of chiropractors and the utilization of chiropractic by older US adults varied widely by region. Increased chiropractic supply was associated with increased chiropractic use, but not with increased chiropractic utilization intensity. Utilization of chiropractic care is likely sensitive to both supply and patient preference.

Chiropractic Use in the Medicare Population: Prevalence, Patterns, and Associations With 1-Year Changes in Health and Satisfaction With Care

“…The propensity score models used state chiropractor supply data for the interview start year, in addition to other known risk factors to estimate a probability of chiropractic use for each person-year observation. 4,5,40–42 Once the propensity scores were estimated, the inverse probability of treatment weights (IPTW) were calculated and multiplied by the one-year sample weight provided in the MCBS to obtain a propensity score adjusted sample weight.…”

A spatial analysis of the geographic distribution of musculoskeletal and general practice healthcare clinics in Auckland, New Zealand

“…SID suggests that new clinics may benefit from locating in areas already supplied with similar healthcare services, thus creating a pattern of supply and demand which is not geographically balanced. Much research has shown evidence of SID in conventional medicine (Léonard et al, 2009), and increased chiropractic supply has also been associated with increased chiropractic use (Whedon et al, 2012). However, analysis of SID requires measurement of both supply and demand, and therefore suggestion of the influence of SID in this study is only speculative.…”

“…These findings may also in turn have been influenced by other factors, such as the socioeconomic status of the surrounding residential areas creating a more desirable location for a clinic. A notable point is that Whedon et al (2012) only examined the use patterns of patients seeking care funded by health insurance.…”

“…Whedon, Song, Davis, and Lurie (2012) analysed the supply and use of chiropractic services amongst health insurance users in the United States, using patient data supplied by health insurance providers and GIS software to perform small area analyses. The results of these analyses indicated that chiropractic supply and use were positively correlated (Spearman 0.68; p = 0.001), (Whedon et al, 2012), which may suggest a degree of SID exists for chiropractic treatment in the United States. These findings may also in turn have been influenced by other factors, such as the socioeconomic status of the surrounding residential areas creating a more desirable location for a clinic.…”

Regional Supply of Chiropractic Care and Visits to Primary Care Physicians for Back and Neck Pain

“…This finding is not surprising considering the chiropractic profession began in the Midwest (specifically in Davenport, Iowa, which had the highest supply of chiropractors of all HRRs). 8,26,27 Given that the supply of physicians in general exhibits a different pattern, 28 it may raise questions about the role of chiropractic care in improving access to care (particularly in rural locales). Previous studies have examined the potential role of chiropractic care in improving access to care.…”