US veterans use vitamins and supplements as substitutes for prescription medication

Vitamins and supplements are the most commonly used form of complementary and alternative medicine in the United States. Growing research suggests that patients substitute vitamins and supplements for their prescription medications. The reasons might include cost of prescription medications and discordant patient and doctor health belief systems.

To investigate the prevalence of substitution of vitamins and supplements for prescription medications among veterans who receive care in the VA health care system and whether substitution is associated with prescription rationing due to cost, treatment beliefs, or distrust of the health system.

Cross-sectional observational survey.

Primary care patients (n=275) at the Philadelphia VA Medical Center.

Medication substitution, prescription medication rationing, treatment beliefs, and health system distrust were measured with structured instruments. Multivariate logistic regression was performed with substitution as the dependent variable.

A significant number of primary care patients in the VA system use vitamins and supplements 206 (75%). The prevalence of medication substitution is high 48 (18%). Medication substitution is strongly associated with prescription rationing due to cost (adjusted odds ratio 6.3, 95% confidence interval: 2.0-19.5, P=0.001). Similarly, greater belief in complementary and alternative approaches to care positively predicts medication substitution (adjusted odds ratio 1.08, 95% confidence interval: 1.01-1.15, P=0.011). There is no significant association between health system distrust and likelihood of medication substitution.

Medication substitution is prevalent in this sample of inner city primary care patients who receive care in the VA system. Cost of prescriptions and belief in the value of complementary and alternative approaches to care appear to be associated with this patient-driven treatment decision.