To measure is to know?

The quote we are probably all familiar with, is the one expressed by Lord Kelvin, who lived from 1824 until 1907: “To measure is to know. If you cannot measure it, you cannot improve it”. Nowadays, in my research I focus on the assessment of persistent pain in patients and in this editorial I purposely use the term persistent pain instead of chronic pain. This because the term chronic pain obscures the patient’s view of a ‘potential pain free-horizon’, which makes suffering worse. McCaffery stated, already in 1968, that pain is whatever the experiencing person says it is, existing whenever the person says it does [1]. The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage” [2]. Important to say is that persistent pain is a disease in its own right and should be treated as such [3].

Measuring pain is challenging. There are many reasons to assess pain in patients. ‘Positive reasons’ to assess patients’ pain are for example to measure pain control, the modification of interventions, and monitoring and follow-up. On the other hand, there are also several ‘negative reasons’ to evaluate pain in patients like financing, physician quality reporting systems and regulatory requirements. In daily clinical practice and in research settings we try to measure patients’ pain by use of scales, questionnaires, quantitative sensory testing and physical/functional testing. Following the previously stated definitions of pain, it becomes clear that the experience of pain is unique in every patient and affects not only the biological aspects of life (poor sleep, functioning, etc.) but also the psychological (for example feeling disbelieved and having a poor mental health) and social dimensions (such as a decreased participation in daily life or absenteeism from work). To date, there are no direct measurement instruments to address patients’ pain in all of its dimensions at once. As the intensity of patients’ pain and the perceived unpleasantness are not directly related to the level of suffering from the pain having control over the pain is of major importance for patients [4]. In my opinion we should add more objective measures related to daily life in clinical practice and in research to emphasize the psychological as well as the social influences to patients’ pain, besides the biological aspects. This will lead to a more inclusive assessment of patients with (persistent) pain. As a result, the measurement of the intensity of pain and perceived unpleasantness becomes less important and a more encompassing assessment of suffering and wellbeing becomes of greater importance.

I was asked to select an article in this issue which is made freely available. Reading the abstracts of this issue, the article written by Suélem de Lorena and colleagues [5] caught my eye. This group has studied the effectiveness of an active physical self-care support program with an emphasis on stretching exercises in female patients diagnosed with fibromyalgia in comparison to a control group. They concluded that stretching exercises were effective for the improvement of patients’ physical performance and that patients experienced a lower impact of the disease. However, there was no statistical significant difference on patients’ reported pain as measured by the visual analogue scale. In light of what I have written above, it is not remarkable that patients’ pain was not lowered after the 10-weeks self-care support program emphasizing stretching exercises. Pain was not the primary outcome but functioning which might as well lead to more wellbeing and less suffering. It would be interesting to read a follow-up by this group to see how the patients are doing after, for example, three or six months. Do the patients still experience the benefits of this program, has the perceived pain intensity and unpleasantness changed during the past period and what is the momentary impact of the disease on suffering and wellbeing? A lot of questions, but: to measure is to know and in the end we can make a difference for patients with persistent pain.

Enjoy reading this issue, and always keep in mind that a patient is more than the outcome of a set of measuring instruments.