Een nieuwe editie van de rubriek “Gastcolumn van de hoogleraar”. Periodiek schrijft een hoogleraar (met als werkgebied fysiotherapiewetenschap) een column op onze website. Dit keer de beurt aan Prof. Dr. Jaap H. van Dieën.

Personalized health care

Not being a clinical researcher but doing research that I believe may be useful for clinical practice, I sometimes blunder into interesting debates on clinical practice and related research. Quite recently I was invited to talk about research we had done on motor control in patients with low-back pain. More specifically I was asked to consider the question whether testing of motor control changes in patients with low-back pain might form a basis for personalization of treatment. This led to an interesting exchange of ideas with clinicians and fellow researchers and we are currently preparing a consensus paper on this topic. The discussion and follow-up gave rise to some more general reflections on personalized physiotherapy in relation to low-back pain that I would like to share here.

In traditional health care, all patients with the same diagnosis received the same cure and care. In recent years, individually tailored interventions have become more ‘en vogue’. Under the title of precision medicine, personalized medicine, targeted treatment, or personalized health care, the aim is to tailor cure and care to the patient’s unique health conditions, to obtain better effects than with a one-size-fits-all approach. Personalized health care receives wide attention in the media and even in politics, with president Obama referring to it in his state of the union, to the extent that one may ask whether this presents a revolutionary change in health care or a hype.

Many physiotherapists would argue that their approach has always been one in which treatment was individually tailored and that personalized health care thus is a hype, created by late converts to the idea coming from other less enlightened disciplines. This has often been used as an argument against clinical trials on physiotherapy interventions, in which, so it is assumed, treatment needs to be standardized.

Let us take low-back pain and more specifically stabilization exercises in patients with chronic low-back pain as an example. These exercises target control over trunk posture and movement to allow patients to better resist mechanical perturbations and to avoid poorly controlled and potentially pain provoking movements. Clinical trials have assessed interventions such as this one, often with somewhat disappointing results. Typically there is a positive effect compared to no intervention, but the effect size is small, implying that many patients do not benefit or benefit very little from the exercises. One might rightfully argue that some low-back pain patients do not need stabilization exercises and in fact some studies shave shown that low-back pain patients may have better control over trunk posture and movement after perturbations than healthy subjects, which may simply be a matter of priority. The small effect of stabilization exercise would then be perfectly understandable and the implication would be that targeted treatment would be more successful. It is important to note here that similar stories can be told about other types of interventions, like strength training, manipulation, or graded behavioral therapy.

So, is the alternative to dismiss clinical trials in physiotherapy? I don’t think so. Not only would this, in this day and age, marginalize physiotherapy, but also the idea that clinical trials and personalized medicine cannot be matched is wrong. The question is what it takes to do clinical trials on a personalized intervention. Quite obviously the key requirement would be that the protocol for personalization of treatment can be communicated and is shared between clinicians. One might argue that it is a reasonable requirement for any form of clinical practice for it to be based on a communicable rationale shared within a profession, but I am not convinced that this is always the case.

To be more specific, a protocol for personalized treatment should, in my opinion, consist of a set of diagnostic procedures or tests, combined in a decision tree that guides which procedures to apply based on outcomes of previous procedures and tests. Ant it should provide a heuristic for treatment choice based on all diagnostic outcomes. Perhaps one might call this a pre-structured way of clinical reasoning. Obviously, tests to be applied need to have good inter-rater reliability, otherwise the protocol is not communicable. Practical applicability is often first on the list of requirements that people propose regarding tests to be used in such a protocol. Personally, I think that this point is overemphasized. Expensive and time-consuming diagnostic procedures can be cost-effective. It may be good to keep in mind that the costs of low-back pain to society are huge, so more effective interventions, even if expensive, do stand a chance of being cost-effective. Putting practical requirements first often leads to the use sub-optimal diagnostic procedures with low inter-rater reliability, which will certainly not be cost-effective.

What has been done so far towards personalized physiotherapy in low-back pain? Well, subgrouping of patients, which can be considered as a step towards personalization, has been on the agenda for several decades. Several systems for subgrouping LBP patients have been proposed in the literature. Among these some have been more extensively studied, most notably the McKenzie classification, the Treatment Based Classification, the Multi-Dimensional Clinical framework, formerly named O’Sullivan Classification, and the Movement System Impairment classification. Classification of patients into subgroups is mainly done based on anamnesis, visual observation of movement tasks and pain provocation. For these classification methods inter-rater reliability seems reasonable, although results leave something to desire.

The clinical results of treatment based on subgrouping, require more study, but appear to be somewhat disappointing. For example, two randomized controlled trials with a focus on matching exercise to subgroups showed no benefit over general exercise interventions in the long-term primary outcomes of pain and disability in people with chronic low-back pain. Another randomized clinical trial showed more promising results, with better outcomes of the intervention based on subgrouping. However, it is not clear whether subgrouping or the use of biofeedback in the subgroup based intervention accounted for this and still the difference in effect with conventional treatment was relatively small.

One might at this stage ask whether current subgrouping systems provide the way forward for treatment of low-back pain and I have my doubts. The rationale behind existing subgrouping systems is not always clear; they are based on clinical experience of sometimes a single clinician. While these developers have achieved somewhat of a guru status, the underlying theory is in places inconsistent. This leads to subgroups not being mutually exclusive and to patients not fitting into any of the subgroups. In addition, it is widely believed that chronic low-back pain is multi-factorial. If this indeed is the case, subgrouping may become an intractable problem and the benefit of interventions targeting the most prominent underlying factors might be negligible compared to a shotgun multi-factorial approach. Finally, many of the underlying factors likely present a continuum, whereas subgrouping requires dichotomization. An approach in which patients are profiled based on continuous measures of relevant factors, yielding an individual profile that provides guidance for treatment choices may be more fruitful. The first challenge will be to select the most important factors to consider in such an approach. Convergence between existing classification systems can likely provide guidance here, but developing a more principled method seems necessary. As many man-made systems that have grown, that have been updated and modified over time, the current subgrouping approach may have reached a state where a redesign is indicated.

 

Prof.dr. Jaap H. van Dieën
Professor of biomechanics
Director of MOVE-AGE (Erasmus Mundus Joint Doctorate Program)

MOVE Research Institute Amsterdam, Department of Human Movement Sciences