Prevalence and Nondisclosure of Complementary and Alternative Medicine Use in Patients With Cancer and Cancer Survivors in the United States

Abstract

This cross-sectional study analyzes the proportion of patients with cancer and cancer survivors who use complementary and alternative medicine (CAM) without disclosing this information to their physicians.

Complementary and alternative medicines (CAMs), defined as therapies used in addition to or instead of conventional therapies, respectively, are frequently used in the United States by patients with cancer and cancer survivors; however, there is concern that these individuals may not disclose CAM use to their physicians.¹ A recently published report from the National Cancer Database found that a small subset of patients who reported CAM use (n = 258; 0.01% of the study population) had worse survival than patients who did not use CAM; this finding appeared to be mediated by refusal of conventional cancer therapy.² Given the potentially serious, adverse, and wide-reaching implications of CAM use (particularly use of alternative medicines) in patients with cancer, an accurate assessment of the prevalence of CAM use is needed. We used data from a comprehensive nationwide survey to conduct a cross-sectional study estimating the proportion of patients with cancer and cancer survivors using CAM and the associated rates of nondisclosure.

Methods

The National Health Interview Survey (NHIS) collects data annually on a range of health indicators for noninstitutionalized, civilian adults.³ In 2012, the NHIS included a supplement on CAM use, as defined by the National Center for Complementary and Alternative Medicine (renamed the National Center for Complementary and Integrative Health).⁴ Data on CAM use and on participant demographics among those reporting a cancer diagnosis were obtained through the Integrated Health Interview Series.⁵ Data analyses for this study were performed from October to December 2018.

Multivariable logistic regressions defined adjusted odds ratios (AORs) and associated 95% CIs for odds of using CAM. Among 1023 participants reporting CAM use, reasons for nondisclosure were reported. Factors associated with nondisclosure of CAM were assessed via multivariable logistic regression. As a sensitivity analysis, rates of CAM use and nondisclosure were reported for participants with a cancer diagnosis up to 2 years prior to survey administration (n = 812). Variables adjusted for in the models are described in Table 1 and Table 2, with weighted percentages reported in the Results section. Statistical testing was 2 sided, with α = .05. Analyses were performed with Stata software version SE 15.1 (StataCorp). The University of Texas Southwestern’s institutional review board deemed the study exempt, and patient written informed consent was not required for this study.

Table 1. Baseline Characteristics of 3118 Participants Stratified by CAM Use and Multivariable Adjusted Odds of Using CAM.

Characteristica	Raw No. (Raw Percentage/Weighted Percentage)b		Multivariable Adjusted Odds of CAM Use
	CAM User	CAM Non-user	AOR (95% CI)	P Value
No. (%)	1023 (32.8/33.3)	2095 (67.2/66.7)
Sex
Male	350 (28.5/29.0)	880 (71.5/71.0)	1 [Reference]
Female	673 (35.6/36.5)	1215 (64.4/63.5)	1.55 (1.26-1.91)	<.001
Age, y
18-55	309 (40.3/38.4)	458 (59.7/61.6)	1 [Reference]
56-65	281 (36.8/37.3)	483 (63.3/62.7)	0.99 (0.75-1.30)	.93
66-75	249 (33.0/33.6)	506 (67.0/66.4)	0.95 (0.71-1.27)	.72
≥75	184 (22.1/22.7)	648 (77.9/77.3)	0.58 (0.43-0.78)	<.001
Race
Non-white	98 (23.2/21.7)	324 (76.8/78.3)	1 [Reference]
White	925 (34.3/34.5)	1771 (65.7/65.5)	1.82 (1.28-2.58)	.001
Ethnicity
Spanish, Hispanic, or Latino	49 (26.8/23.6)	134 (73.2/76.4)	1 [Reference]
Non-Spanish, non-Hispanic, or non-Latino	974 (33.2/33.7)	1961 (66.8/66.3)	1.64 (1.05-2.56)	.03

Abbreviations: AOR, adjusted odds ratio; CAM, complementary and alternative medicine.

^aThe model was also adjusted for insurance status (insured, not-insured), income ($0-$34,000, $35 000-$74,999, $75 000-$99,999, ≥$100 000, unknown), education (none-grade 4, grade 5-12, 1-4 years of college, ≥5 years college, unknown) and years since diagnosis (0-5, 6-10, 11-15, >15), which were not significantly associated with CAM use.

^bSample weighting was used for all analyses to produce nationally representative estimates. Percentages may not add up to 100 due to rounding.

Table 2. CAM Modalities Used by 1023 Participants Stratified by Disclosure and Adjusted Odds of CAM Nondisclosure.

Characteristica	Raw No. (Raw Percentage/Weighted Percentage)b		Multivariable Adjusted Odds of CAM Nondisclosure
	CAM Discloserc	CAM Nondiscloser	AOR (95% CI)	P Value
No. (%)	735 (71.8/70.7)	288 (28.2/29.3)
CAM Modality
Otherd	86 (78.2/76.0)	24 (21.8/24.0)	1 [Reference]
Herbal supplements	309 (85.1/88.2)	54 (14.9/11.8)	0.51 (0.26-1.03)	.06
Chiropractic of osteopathic manipulation	176 (68.8/67.3)	80 (31.2/32.7)	1.91 (0.98-3.75)	.06
Massage	76 (58.9/53.5)	53 (41.1/46.5)	2.97 (1.44-6.13)	.003
Yoga, tai chi, or qigong	50 (58.8/50.4)	35 (41.2/49.6)	3.69 (1.68-8.09)	.001
Mantra/mindfulness/spiritual meditation	33 (44.0/41.8)	42 (56.0/58.2)	5.38 (2.26-12.81)	<.001

Abbreviations: AOR, adjusted odds ratio; CAM, complementary and alternative medicine.

^aThe model was also adjusted for sex (male, female), age (18-55 years, 56-65 years, 66-75 years, >75 years), race (white, non-white), ethnicity (Non-Spanish, non-Hispanic, non-Latino vs Spanish, Hispanic, or Latino), insurance status (insured, uninsured), income ($0-$34,000, $35 000-$74,999, $75 000-$99 999, ≥$100 000, unknown), education (none-grade 4, grade 5-12, 1-4 years of college, ≥5 years of college, unknown) and years since diagnosis (0-5, 6-10, 11-15, >15). The only statistically significant variable among these was ethnicity (Spanish, Hispanic, or Latino ethnicity had lower odds of nondisclosure; adjusted odds ratio, 0.39; 95% CI, 0.16-0.91).

^bSample weighting was used for all analyses to produce nationally representative estimates. Percentages may not add up to 100 due to rounding.

^cRaw column numbers do not add up to total cohort population given 5 participants not reporting CAM type used.

^dTypes of CAM with the lowest number of participants reporting use (n < 50) were combined into the “other” category. These included special diets, acupuncture, homeopathy, movement or exercise techniques, naturopathy, traditional healers, energy healing therapy, biofeedback, hypnosis, and craniosacral therapy.

Results

Among 3118 participants reporting a history of cancer (1230 men and 1888 women; median age, 66 years [range, 18 to ≥85 years), 1023 (33.3%) used CAM in the past 12 months. The most commonly used CAM modality was herbal supplements (363 of 1023 participants, 35.8%), followed by chiropractic or osteopathic manipulation (256 of 1023, 25.4%), massage (129 of 1023, 14.1%), yoga/tai chi/qigong (85 of 1023, 7.6%), mantra/mindfulness/spiritual meditation (75 of 1023, 6.9%), special diets (29 of 1023, 2.9%), acupuncture (26 of 1023, 2.0%), homeopathy (15 of 1023, 1.5%), movement or exercise techniques (11 of 1023, 1.3%), naturopathy (7 of 1023, 0.6%), traditional healers (6 of 1023, 0.4%), energy healing therapy (5 of 1023, 0.6%), biofeedback (5 of 1023, 0.4%), hypnosis (4 of 1023, 0.5%), and craniosacral therapy (2 of 1023, 0.2%). Factors associated with CAM use included white race (AOR, 1.82; 95% CI, 1.28-2.58; P = .001), female sex (AOR, 1.55; 95% CI, 1.26-1.91; P < .001), non-Hispanic ethnicity (AOR, 1.64; 95% CI, 1.05-2.56; P = .03), and younger age (AOR, 1.02 per year; 95% CI, 1.01-1.02; P < .001) (Table 1). Among 1023 participants using CAM, 288 (29.3%) did not disclose CAM use to their physicians. The adjusted rates of nondisclosure for those using herbal supplements was 11.8% and 58.2% for those using mantra/mindfulness/spiritual meditation (Table 2). The most frequently reported reasons for nondisclosure were because the physician did not ask (n = 155 of 288; 57.4%) or participants did not think their physicians needed to know (n = 140 of 288; 47.4%). A smaller proportion of CAM users felt that their physician did not know as much about the therapy (n = 28 of 288; 8.5%), reported they were not given enough time to tell about therapy (n = 12 of 288; 5.7%), expressed concern about a negative reaction (n = 17 of 288; 3.9%), were worried that their physician would discourage use (n = 18 of 288; 3.6%), or reported that physicians discouraged use in the past (n = 11 of 288; 1.9%).

When the cohort was restricted to 812 patients with cancer diagnosed up to 2 years prior to survey administration, 271 (33.4%) reported CAM use, including 231 (28.5%) who did not disclose CAM use to their physician.

Discussion

In this comprehensive national study, 1023 of 3118 (33.3%) participants with a history of cancer reported CAM use in the past year, 288 (29.3%) of whom did not disclose use of CAM to their physician. Individuals diagnosed with cancer may have many motivations for seeking CAM, including persistent symptoms, psychological distress, or to gain a sense of control over their care.⁶ Given the high proportion of patients with cancer and cancer survivors reporting use of CAM in this nationally representative sample, the potential implications of CAM use on oncologic outcomes merits further study. Policy and guidelines should be established to encourage discussion of CAM. Data for this study were collected in 2012; however, this time frame is within those available from other nationwide databases. The NHIS is a US database, thus our results may not be generalizable to international populations. Additional research is needed to assess health outcomes, quality of life, and cost implications associated with CAM use in the oncology patient population.