Our study addresses important questions about CAM use by people with private insurance who have a CAM benefit. Our cohort had fewer people with claims for massage, a similar proportion with claims for acupuncture, and a greater proportion with claims for naturopathic physicians and chiropractors than was seen in privately insured adults who took part in the 2002 National Health Interview Survey (NHIS). We believe the requirement for a provider referral reduced the claims for massage in our population. A survey of our cohort like NHIS would undoubtedly reveal additional use outside of insurance billing. Our study also shows that relatively small proportion of the population use acupuncture, even when it is covered by insurance and that among the privately insured chiropractic is the most commonly used form of CAM in the US and Washington State, 8.3% and 10.9% use respectively. The 5 times greater prevalence in the use of naturopathic medicine in our insured cohort compared to national surveys is likely a regional phenomenon. Western Washington’s 422 actively licensed NDs (Washington State Department of Health, Information Services, personal communication; February 2003) represent approximately 31% of all NDs licensed nationally.1
Even with the above differences noted, the prevalence of CAM use in our claims data is very similar to the NHIS data (13.7% vs. 13.4%). Although we do not know why this is true, it suggests that insurance coverage of licensed CAM providers does not lead to runaway utilization.
As shown in previous population-based surveys, we found that CAM use is greater in certain groups than others. The proportion of insured that fall into these different categories will be one factor determining the prevalence of CAM use. For example, patients who have high expected resource utilization based on risk-adjustment schemes use more CAM than people who use less health care. Other studies using provider visits as a measure of utilization have found similar results.20
Although women were only slightly more likely to use chiropractic than men, they were over twice as likely to use naturopathic medicine, massage, and acupuncture. The treatment of specific medical conditions, such as menopause, account for some of these gender-specific differences. Chiropractic use was substantially more common in smaller counties than in major urban centers. This affirms the important role chiropractors have historically played in rural primary care, where access to conventional providers is more limited.21
Differing benefit structures are probably more CAM friendly than others; requiring a gatekeeper’s recommendation as opposed to self-referral may be the biggest disincentive to insurance financed CAM use. In addition, people will likely self-select into different products based on their expected need for medical services. For this reason we were not surprised to see that CAM use was greater in PPOs than it was in HMO product lines
We did not expect to find that CAM care would account for such a small proportion of insurance expenditures. Eisenberg’s 1997 survey data estimated expenditure for CAM professional expenditures between 21.2–32.7 billion dollars or about 1.9%–3.0% of total 1997 health care expenditures.22
Our estimate that CAM providers accounted for 2.9% of 2002 private insurance expenditures is similar to these earlier national survey data. Payers have resisted covering CAM providers in part because of a fear that coverage would result in large, steadily increasing, and unpredictable expenditures for CAM services, not unlike the history of prescription drug coverage. Our study done six years after the mandated inclusion of CAM benefits in Washington State suggests that this is not going to be the case. We hypothesize several reasons. First, because the typical CAM patient’s emphasis is on the treatment of musculoskeletal pain, the scopes of practice for many CAM providers overlap. This suggests that other CAM services such as massage and acupuncture may compete with the previously covered CAM service of chiropractic care. Second, even though naturopathic physicians, and to a lesser extent acupuncturists, have broader scopes of practice, these services are used by a very small fraction of the population. Third, CAM providers in our study practice a less expensive form of medicine. They provided virtually no inpatient services and as we have previously shown they rarely use expensive diagnostic tools such as imaging technology.23
Our study has several imitations. First, we measured utilization and expenditure not efficacy and value. Even though we found that CAM’s proportion of the insurance dollar is small, 2.9% of over a billion dollars is still a great deal of money. Randomized controlled trials performed for specific CAM interventions clearly show that CAM (like conventional care) is not effective for all of the conditions that it is used to treat, e.g. acupuncture for fibromyalgia.24
Even so, many patients commonly integrate CAM and conventional care25,26
and the extent to which this should be encouraged is unclear. Second, the value to the health care consumer of integrating CAM services into health insurance benefits is still debated in Washington State. The movement toward forms of consumer directed health care will test the consumer’s commitment to CAM services. In theory, the economical nature CAM interventions may be very attractive to patients with high deductible insurance policies and private medical savings accounts. Studies on CAM cost sharing, cost-effectiveness, and medical quality are clearly warranted. Third, although the samples for this study are quite large the population and benefits are always select. The exclusion of Medicaid and Medicare recipients, the uninsured, and self-insured companies mean that our data may be incomparable to some large population-based national surveys. Although we believe our four provider categories capture almost all professional CAM services (96.5% based on NHIS population-based use estimates) at least 11 additional provider groups have been included in national surveys.27
Our study is of national significance as insurance companies in the United States respond to consumer demand for an integrated CAM benefit.28
The Washington State law mandating CAM provider coverage in private commercial insurance products creates a window through which consumer behavior under various CAM and conventional benefit structures can be monitored and the effect on health care expenditures measured. Despite the increase in CAM provider use and a mandatory requirement to include CAM providers in insurance, the overall percentage of insurance expenditures for CAM remains small six years after passage of the requirement. At this time CAM coverage only minimally contributes to increasing health care expenditures and health insurance premiums in Washington. Future studies should evaluate the trajectory of CAM expenditures and the role of CAM in the health care marketplace; especially whether CAM therapies actually substitute for more expensive conventional care. Only then can the total impact of CAM integration on health care utilization be measured.