Letter to the Editor „The Sustainable Effectiveness to Avoid Chronification in Non-Specific, Non-Chronic Back Pain“

With interest, we have read the study by Alt et al. (2020)

(1) However, we could not ignore its limitations and problems and would like to outline some of the most significant ones:

1) Agreed standards of reporting were ignored (2).

2) No study-protocol was pre-registered.

3) Despite it being described in the title and as main aim, there was no definition and measurement of "chronification".

4) The counseling units in both groups differed significantly. The education in the MCG group were based on an outdated biomechanical model that could have negatively affected outcomes (3).

5) The control group received 9 sessions of the same passive interventions, which is not in line with any guidelines for LBP.

6) The described techniques are no specific Maitland-techniques and their application was not in line with the clinical reasoning in the concept itself.

7) All participants were physically inactive despite this not being defined in the in-/ exclusion criteria.

8) We could not find any results about a group comparison of the measured changes, although a Friedman test was announced in the method.

9) No decimal places in the reported mean values and standard deviations in table 2 were given. It is unlikely that those were not found and not reporting them is frankly wrong.

10) The gender data presented in table1 differ from the percentages given in the methodology.

In summary, we would argue that the significant limitations make the presented conclusions highly debatable. The inadequate reporting and the lack of pre-registered protocol are serious problems and the main aim of the study was not addressed. Furthermore, the selected participants and treatment strategies, seemed to strongly favor the active group over the control. The presentation of the results appears to be incomplete, error-prone and does not allow appropriate analysis.

Therefore, we are very worried about the planned extension of the study. We feel it would be ethically problematic to include further participants in a study that does not add any clinical or scientific benefit and, in the worst case, negatively impacts on patients´ recovery. We would also like to emphasize the fact that in the Canton of Aargau in Switzerland, the Ethics Committee Northwestern and Central Switzerland is responsible for clinical trials and not the IST-University Düsseldorf.