Saturday, October 1, 2011

Placebo by Proxy: How Does It Affect Pain Care?

Placebo Research consistently finds that patients’ beliefs and expectations of benefit from pain treatments can influence their responses, and that a considerable component of pain relief might relate to placebo effects. An often overlooked phenomenon is how the beliefs and expectations of healthcare providers and family members — engendering a placebo by proxy effect — also might affect a patient’s response to pain management therapies.

Placebo effects in general, including their complexities and importance for pain management practice, have been discussed in a series of Pain-Topics UPDATES [here]. Now, in an editorial last August 2011 in the British Medical Journal, David J Grelotti and Ted J Kaptchuk from Harvard Medical School suggest that clinicians’ and family members’ feelings, attitudes, and perceptions about a patient’s medical treatment may lead them to conclude that it is helping the patient, even in the absence of measured physiological benefits or positive indications in the patient [Grelotti and Kaptchuk 2011]. They further note…

“These feelings and perceptions may arise when placebos, including ‘impure’ placebos, such as active drugs or operations that have no effect on the disease process, are used in clinical practice and research settings. Because these feelings and perceptions are not accounted for in descriptions of the placebo effect and can exist independently of any placebo effect on the patient, they can be described as placebo effects by proxy, or placebo by proxy for short.”

The authors maintain that placebo by proxy has important implications, but the phenomenon is underappreciated and rarely discussed. A common scenario is when, urged by a patient’s family, a practitioner writes a prescription knowing that the chances of it actually helping the patient are slim. This increases psychological comfort in the family (eg, relief from worry), altering their behavior toward the patient (such as being more attentive or nurturing), and it may indeed foster a favorable response in the patient; although, that response is doubtfully related directly to the prescribed treatment.

In addition to influencing clinical decision making, Grelotti and Kaptchuk suggest that placebo by proxy could influence estimations of treatment outcomes in research trials, especially when the perceptions of clinicians or family members are taken into account or even favored over objective markers of patient response. For example, a placebo by proxy phenomenon may explain findings from meta-analyses where improvements noted by observers are much greater than those reported by patients. As another example, the authors mention a study of treatment for irritable bowel syndrome finding that the response rate for improvement in the placebo group as rated by physicians was 53.0%, compared with only 37.4% as rated by patients themselves (a significant difference; P=0.005).

Placebo by proxy is likely influenced by the same mechanisms that underlie all placebo effects, such as expectation, seeing other patients respond to the same drug/placebo, associative learning such as conditioning, a supportive physician-patient relationship, and reduced anxiety. And, placebo by proxy and actual placebo effects may interact to create greater positive change. For example, the editorialists note…

“If clinicians and family members feel empowered and optimistic about a disease, the patient’s environment can become less stressful and more supportive. Clinicians and family members may react to placebo [effects] by smiling more, paying more attention to the patient, promoting treatment adherence, encouraging the patient to engage in new activities, or creating other targets for behavioral change. In this way, placebo by proxy may elicit changes in the patient’s psychosocial context that mediate the placebo effect.”

However, Grelotti and Kaptchuk warn that placebo by proxy effects might also cause harm. If treatment-related decisions are unduly weighted toward providing psychological benefits to persons other than the patient, the patient might bear the risks of treatment without significant benefits. Even therapies with the possibility of exerting only marginal effects, or merely placebo responses, cost money and may not be benign in that they could incur certain side effects.

Placebo by proxy also may create a false sense in observers that a patient is getting better and thereby prevent consideration of more appropriate treatments. Or, false perceptions by caregivers of patient improvement and greater functionality might lead to neglect of the patient’s daily needs. The authors stress that, “Placebo by proxy is probably more likely to cause harm when decisions are made in the absence of clinical evidence and when patients cannot make decisions for themselves.”

Grelotti and Kaptchuk conclude that treatment benefits could be maximized and harms avoided if placebo by proxy is taken into account when making clinical decisions. For example, an awareness of placebo by proxy may prompt clinicians to question attachments by family members to treatments that are not supported by evidence. On a positive note, they state, “it may be possible to boost the psychological benefit of a patient’s treatment by generating appropriate enthusiasm for treatment among those involved in the patient’s care.”

COMMENTARY: While Grelotti and Kaptchuk were not specifically addressing pain management in their editorial, the possibility of a placebo by proxy phenomenon in pain care settings no doubt exists and could be important. An underlying mechanism seems simply guided by the old maxim: The primary influence on people is other people.

As Grelotti and Kaptchuk observe, most treatment-related decisions are shared and patients may agree to therapies about which their healthcare providers and family members are most enthusiastic, for whatever reasons. Clinicians must be aware of possible placebo by proxy effects when guiding healthcare decisions and evaluating treatment response. For example, a favored therapy of the pain practitioner, or one strongly advocated by family members, might be entirely wrong for the individual patient.

In such cases, encouragement by the practitioner, and positive reinforcement of family members, might indeed foster a response in the patient — although it only might be a short-lived placebo effect. Especially in the case of pain, the patient might attest to beneficial effects if only to please these other persons and justify their hopefulness.

Two further aspects of placebo by proxy, alluded to in the editorial, are important:

  • First, treatment decisions influenced in this way, sometimes based more on beliefs and perceptions than sound science, could delay the pursuit of more beneficial therapies. This is a common complaint that some observers have expressed about certain complementary and alternative medicine (CAM) therapies, which may have strong popular support but are weak in terms of substantial research evidence demonstrating their efficacy.

  • Second, it seems apparent that placebo by proxy may exert significant powers — either for good or for harm — over patients who are most easily swayed; the elderly, children, or those with cognitive impairments. It stresses the critical importance of trying to gauge true effects in the patient, independent of practitioners’ or family members’ feelings and beliefs about how a treatment should work or is working.

Of course, the concept of placebo by proxy adds yet another level of complexity to the pain management conundrum. Practitioners and a patient’s family members need to feel empowered and optimistic about the promise of success afforded by a pain management treatment; however, they need to also be cautious that their own beliefs and expectations do not supersede true benefits gained by the patient. This seems worthy of thoughtful consideration.

REFERENCE: Grelotti DJ, Kaptchuk TJ. Placebo by proxy [editorial]. BMJ. 2011;343:d4345 [abstract here].