During my time in the United States, many professorial acupuncturists asked me a recurring question about the treatment of patients with back pain: "What is your treatment rate?" This was the most common query I encountered in my lectures. My typical response would be, "Over 90%." On the surface, this might seem impressive, but let's dig a bit deeper.
Consider this fact: The 2000 UK guideline for the management of low back pain in primary care states that "90% [of cases] will recover within six weeks." This raises an intriguing question: If 90% of back pain cases resolve naturally within six weeks without any treatment, what does it mean if acupuncture has a 90% treatment rate?
The answer is simple yet surprising: it might not mean much at all. This scenario underscores the importance of controlled studies in medical research. To truly understand the effectiveness of a treatment, we need a control group for comparison. Without one, we have no way of knowing if the observed recovery is due to the treatment itself, natural healing over time, or a combination of both.
So, what exactly is a treatment rate?
In research, a treatment rate often refers to the proportion of subjects in a study who have achieved a certain level of improvement or recovery with a particular treatment. It represents the effectiveness of the treatment in the studied population. For example, a 90% treatment rate means that 90% of the subjects showed improvement or recovery after receiving the treatment. However, this concept cannot state the effectiveness of an intervention in a general context. It can only be useful when the disease or problem is incurable or has a very high mortality rate.
Let's consider another example. Suppose you recruit 100 participants for an experiment designed to investigate the effect of acupuncture on blood pressure. The participants have their blood pressure measured before receiving acupuncture, and then again after a 30-minute acupuncture session. The measurements reveal a statistically significant difference in blood pressure before and after the acupuncture treatment. Can you conclude from this experiment that acupuncture is effective at reducing blood pressure?
There's a catch. Simply lying down comfortably for 30 minutes can naturally cause blood pressure to decrease. Without a control group of participants who lie down for 30 minutes without receiving acupuncture, you cannot definitively attribute the decrease in blood pressure to the acupuncture treatment. This again illustrates the importance of controlled studies in determining the actual effectiveness of a treatment.
A well-structured controlled study has an experimental group that receives the treatment and a control group that does not. The control group might receive a placebo, the standard treatment, or no treatment at all. By comparing the outcomes in these two groups, researchers can then isolate the effect of the treatment from other confounding factors.
In the context of acupuncture for back pain, a controlled study could involve two groups of patients: one receiving acupuncture and the other receiving no treatment or a placebo. If the acupuncture group shows significantly better recovery than the control group, we can confidently say that acupuncture is effective. However, if there is no significant difference between the groups, we may need to question the efficacy of acupuncture in this context.
The takeaway is this: Treatment rate alone, devoid of context, can be a misleading indicator of efficacy. Understanding the importance of controlled studies, and their role in establishing a cause-and-effect relationship, is fundamental to interpreting and evaluating medical research. Any claims of treatment effectiveness should always be based on well-conducted, controlled studies. Only then can we avoid falling into the trap of attributing natural recovery to the effect of a treatment.