Association Between Use of Unconventional Therapies and Conventional Medical Services

Context The terms alternative and complementary medicine suggest 2 contradictory possibilities. Whether individuals use unconventional therapies as a substitute for or as an "add on" to conventional medical treatments is uncertain.

Objective To determine the association between use of unconventional therapies and conventional medical care in a national sample.

Design, Setting, and Participants The 1996 Medical Expenditure Panel Survey was distributed to a probability sample of the noninstitutionalized civilian US population. Of 24,676 individuals responding (77.7% response rate), 16,068 adults 18 years or older were included in the analysis.

Main Outcome Measures Visits to practitioners for unconventional therapies and conventional medical services, including number of inpatient, outpatient, and emergency department visits and use of 8 types of preventive medical services (blood pressure, cholesterol level, physical examination, influenza vaccination, prostate examination, breast examination, mammography, and Papanicolaou test).

Results During 1996, an estimated 6.5% of the US population had visits for both unconventional therapies and conventional medical care; 1.8% used only unconventional services; 59.5% used only conventional care; and 32.2% used neither. Compared with those with only conventional visits, those who used both types of care had significantly more outpatient physician visits (7.9 vs 5.4; P<.001), and used more of all types of preventive services except mammography. These groups did not differ significantly in inpatient care, prescription drug use, or number of emergency department visits. Individuals in the top quartile of number of physician visits were more than twice as likely as those in the bottom quartile to have used unconventional therapies in the past year (14.5% vs 6.4%; P<.001). The association between unconventional treatments and physician visits remained after adjusting for potential confounders and across different types of unconventional treatment.

Conclusions In this sample, use of unconventional therapies was substantially lower than has been reported in previous national surveys, but was associated with increased use of physician services. From a health services perspective, practitioner-based unconventional therapies appear to serve more as a complement than an alternative to conventional medicine.

Interest in unconventional therapies in both the scientific literature and the popular press has increased exponentially during the last decade.¹ This growth has spurred a need both for scientific trials of specific treatments and health services research examining patterns and correlates of these services in the "real world."² From both a clinical and health policy perspective, one of the most salient issues is the degree to which use of unconventional therapies is associated with patients' use of mainstream medical treatment.^3,4

The current nomenclature reflects several potentially contradictory notions of the relationship between these 2 systems of care. The term alternative medicine implies that these treatments are substituting for conventional therapies, whereas the term complementary medicine suggests that the 2 are used in conjunction. Complementary and Alternative Medicine, the name used by the new center at the National Institutes of Health overseeing research in the area, appears to acknowledge both possibilities.⁵ To avoid the potential service use implications of these terms, we use the term unconventional medicine, the label used in the first national survey of these forms of care,⁶ throughout this article.

Several studies suggest that many individuals use unconventional therapy in conjunction with mainstream medical treatment.^6-9 Moreover, patients generally report using such therapies to augment their medical care rather than as a result of dissatisfaction with mainstream medicine.^10-12 Nonetheless, there remains a perception among clinicians and in the popular press that unconventional treatments represent a rejection of, and challenge to, the mainstream medical system.^13,14

The Medical Expenditure Panel Survey (MEPS) is the first national probability survey to gather data about use of visits for unconventional therapies in the context of a detailed survey including data on health insurance, health status, and use of different types of medical services. The sample size is more than 4 times larger than any previous survey of unconventional therapies in the United States, and the sampling techniques of this survey make it highly representative of the general US adult population.^15,16 Using data from that survey, this study examines the relationship between use of unconventional therapies and conventional medical care in the United States.

The MEPS is conducted to provide nationally representative estimates of health care use, expenditures, sources of payment, and insurance coverage for the US civilian noninstitutionalized population. The 1996 MEPS used the 1995 National Health Interview Survey as the sampling frame for the survey.¹⁷ The subsample selected for the 1996 MEPS consisted of 10,597 National Health Interview Survey households who responded. Approximately 4% of the interviews were administered in Spanish; the remainder were conducted in English.

Overall, 24,676 individuals responded to the core MEPS household interview, representing a joint National Health Interview Survey-MEPS response rate of 77.7%. For the purposes of this study, we included all individuals 18 years or older who responded to the survey (N=16,068).

All MEPS participants were asked a set of questions about visits to practitioners of unconventional therapies during the past year. These included a series of questions about use of chiropractic services. A separate section asking about use of unconventional therapies began with the following probe: "In order to get as complete a picture as possible of all sources of health care, we would also like to ask about the use of other forms of health care, including treatment you may have previously told me about, such as the treatments shown on this card. Frequently this type of care is referred to as complementary or alternative care. During the calendar year 1996, for health reasons, did you consult someone who provides these types of treatments?" The card contained the following categories: acupuncture; nutritional advice or lifestyle diet; massage therapy; herbal remedies purchased; biofeedback training; training or practice of meditation, imagery, or relaxation techniques; homeopathic treatment; spiritual healing or prayer; hypnosis; traditional medicine, such as Chinese, Ayurvedic, American Indian, etc; and other complementary or alternative treatments.

If the response was "yes," the respondent was asked to specify which of the therapies on the list had been received. Multiple types of service use by 1 person were possible. For the purpose of this study, visits in which unconventional therapies were provided through a physician were considered to be conventional.

The total number of conventional outpatient services for 1996 was calculated as the sum of office-based and outpatient hospital-based physician visits. MEPS interviewers asked about the number of emergency department visits and the number of inpatient discharges that occurred during that year.

For each respondent, a series of questions was asked about receipt of preventive care or screening examinations within the past year, including the following: blood pressure taken by a physician, nurse, or other health care professional; cholesterol level; complete physical examination; influenza vaccination; prostate examination; Papanicolaou test; breast examination; and mammography.

Respondents were asked to rate their physical and mental health according to the following categories: excellent, very good, good, fair, and poor. In addition, the instrumental activities of daily living help or supervision variable was constructed from the following question: "Due to an impairment or a physical or mental health problem . . . do [you] receive help or supervision using the telephone, paying bills, taking medications, preparing light meals, doing laundry, or going shopping?" Difficulty in activities of daily living was defined as a positive response to the question: "Due to an impairment or a physical or mental health problem . . . do [you] receive help or supervision with personal care such as bathing, dressing, or getting around the house?"

A first set of analyses compared demographic characteristics, health status, and use of unconventional therapies across individuals in 4 groups: those who used both conventional medicine and unconventional therapies, conventional medicine only, unconventional therapies only, and neither type of medicine. Second, use of different types of medical services was compared between individuals who used both conventional medicine and unconventional therapies and those who used conventional medicine only. Third, to understand whether high users of conventional care had distinct patterns of unconventional service use, a set of analyses compared use of unconventional therapies between individuals in the bottom and top quartile of conventional service use.

Two-stage multivariate models were constructed to assess the association of various unconventional therapies with likelihood of any visit and number of physician visits among conventional service users. The first stage used logistic regression by modeling any physician visit as a function of a particular type of unconventional service use. The second stage used linear regression to calculate least-squares estimates for mean number of physician visits associated with each of the unconventional therapies, adjusting for potential confounders. All models controlled for self-reported physical health status, age, sex, race, education, geographic region, and insurance status.

Because of the nonnormal distribution of utilization data, nonparametric methods were used for all tests comparing continuous variables. For bivariate comparisons, the Wilcoxon signed rank test was used to generatez scores for differences between means. In multivariate analyses, continuous variables were first transformed into ranks, and ordinary least-squares regression was then used to compare differences between ranked scores.¹⁸ SUDAAN (Research Triangle Institute, Research Triangle Park, NC; statistical package with appropriate weighting and nesting variables) was used for statistical comparisons and to generate weighted prevalence estimates for the US population.

During 1996, an estimated 6.5% of the US population had visits for both unconventional therapies and conventional medical services, 1.8% used only unconventional services, 59.5% used only conventional care, and 32.2% used neither. These percentages are weighted to account for the survey's complex sampling design.

Table 1 presents the characteristics of individuals using neither, 1, or both systems of care. Compared with individuals who used conventional services only, users of both unconventional therapies and conventional medical services were more likely to be female, white, more educated, and live in the West. There were no significant differences between the 2 groups in self-reported physical or mental health, difficulties with activities of daily living, or difficulties with instrumental activities of daily living. Those using unconventional therapies did report poorer physical health status than those using no services (6.2% vs 0.5%; χ²=4.5; P=.02).

Chiropractic, which was used by 3.3% of the survey population, was the most common unconventional therapy reported, followed by massage (2.0%), herbal remedies (1.8%), spiritual healing (1.4%), nutritional advice (1.1%), acupuncture (0.6%), meditation (0.5%), homeopathic remedies (0.4%), hypnosis (0.1%), biofeedback (0.1%), and other therapies (0.4%) (Table 2).

Compared with those who used unconventional therapies only, those who used both conventional medical care and unconventional therapies were significantly more likely to use chiropractic services (42.8% vs 28.1%; χ²=9.3; P=.002) and significantly less likely to use spiritual healing (1.3% vs 22.6%; χ²=6.8; P=.009). Use of other unconventional services was similar between those using 1 or both systems of care.

Only 2.5% of those with practitioner visits for treatments identified as potentially unconventional had those services provided by a physician. These services were classified as conventional for all subsequent analyses.

Among users of both unconventional therapies and conventional medical care, 8.8% reported that they had been referred for their unconventional therapies by a physician. Fewer than one fifth of those who had both types of visits (19.7%) had told a physician about their use of unconventional services.

Compared with those individuals using conventional services alone, those using unconventional therapies and conventional medical care made significantly more physician visits, and were significantly more likely to report having obtained 7 of the 8 listed preventive services (Table 3). There was no significant difference between the 2 groups in emergency department visits, inpatient discharges, or prescription drug use.

The group in the lowest quartile of use of medical services (low users) made only 1 physician visit during the previous year, whereas the highest quartile of medical service users (high users) made 7 or more physician visits during that time. Compared with low users, high users of medical care were older more likely to be female, white, less educated, and to have health insurance. High users reported significantly more impairment on all measures of health status than did low users (Table 4).

Use of unconventional therapies was more than twice as common among high users than among low users of conventional services (14.5% vs 6.4%; χ²=69.6; P<.001). Compared with low users, high users were significantly more likely to use chiropractic therapy, acupuncture, massage, herbal remedies, meditation, and spiritual healing.

The association between visits for unconventional therapies and physician visits remained robust across a variety of unconventional treatments, and after adjusting for potential confounders (Table 5). Overall, having any visit for unconventional therapies was associated with an approximately 2-fold increase in the odds of having a physician visit. Among those with physician visits, having a visit for unconventional therapies was associated with a two-thirds increase in number of physician visits.

Five of 12 unconventional therapies were associated with a significantly increased likelihood of a physician visit, and 8 therapies were associated with an increased number of such visits among users. No categories of unconventional therapy were associated with a significant reduction in either likelihood or number of conventional services.

The study suggests that practioner-based unconventional therapies serve more as a complement or add-on than as an alternative to conventional medicine. Only 1.8% of the population made visits for unconventional therapies in the absence of visits for conventional medical care, and use of unconventional therapies was consistently associated with an increased likelihood and number of physician visits.

The survey found substantially lower rates of use of unconventional therapies than have been reported in national telephone surveys.^6,7,10 In part, this is likely a function of the MEPS focus on practitioner-based therapies. In addition, the differences in prevalence may reflect the MEPS sampling design. Because less educated and poorer individuals use fewer unconventional services than the general population,⁸ the inclusion of non-English speakers and individuals without telephones in the MEPS survey may provide a more representative view of practitioner-based unconventional therapies in the United States than has been available using telephone surveys.

Several mechanisms could explain the consistently positive association between unconventional therapies and conventional medical services. First, the relationship could be causal if physician visits led to greater use of unconventional therapies or vice versa. However, only a small minority of such visits occurred as a result of physician referrals, and physicians were not aware of more than four fifths of visits for those services.

A second possibility is that greater health care needs led individuals to seek greater use of both unconventional therapies and conventional medical services. While the study had limited measures of illness burden, there was no difference in any of the 4 self-reported health measures between respondents who had physician visits only, and those who had those visits in conjunction with unconventional therapy. Poor health status appeared to drive use of health services in general, that is, those using no services reported better health than those using either conventional medical services or unconventional therapies. However, poor health was not associated with increased use of unconventional therapies over and above conventional medical care.

The literature on "high utilizers" of conventional medical services may provide some insights into the association between use of conventional and unconventional services. In both inpatient¹⁹ and outpatient²⁰ settings, less than 15% of the population uses more services than the remaining 85% of the population. As in our study, high users tend to be sicker than the general population, and frequently have mental health problems as well as medical comorbidity.²¹ However, self-reported health status has been found to explain less than 5% of the variance in predicting high-user status, and adding demographic and other covariates still typically cannot account for the vast majority of this variance.²² The persistence of these patterns may be 1 reason that early prevention initiatives in these groups have rarely been shown to offset their costs though reduction in future health care expenditures.^23,24 For many of these patients, attitudes and learned patterns of behavior may be as important as specific health care needs in driving use of health services.

This study has several limitations. First, there is no consensus in the scientific community as to which therapies should and should not be considered unconventional. The original definition (lack of inclusion in medical schools or availability in US hospitals⁶) has become a moving target as these therapies are increasingly integrated into academic curricula and insurance packages.²⁵ Although the categories defined as unconventional in the MEPS are similar to those in other national surveys, including or excluding particular therapies can substantially change prevalence estimates.

Second, the survey examined only unconventional therapies delivered through a practitioner. Thus, the findings address the interaction between the 2 practitioner-based systems of care, rather than self-administration of either conventional (eg, over-the-counter medications) or unconventional (eg, dietary supplements) therapies. Individuals who receive unconventional therapies on their own might be healthier, might use fewer medical services, or both, than those receiving that care through a practitioner. Further research is warranted to examine use patterns of individuals who primarily obtain unconventional services through self-care.

The findings from this study, in conjunction with the previous literature, suggest that practitioner-based unconventional therapies are generally not a substitute for conventional medical care, but that individuals who use unconventional services are relatively heavy users of both types of care. Ultimately, understanding more about this group of patients may help provide a better understanding of the interface between the 2 systems of care.