Emmylou Beekman

Course length of 30 metres versus 10 metres has a significant influence on six-minute walk distance in patients with COPD: an experimental crossover study

QUESTIONS Do patients with chronic obstructive pulmonary disease (COPD) achieve a different distance on the six minute walk test (6MWT) conducted on a 10m course versus on a 30m course? When assessing the distance on a 6MWT conducted on a 10m course, is it valid to use existing reference equations that were generated on longer courses? DESIGN A randomised double-crossover experimental study. PARTICIPANTS Forty-five patients with COPD in primary physiotherapy care. INTERVENTION All patients performed a 6MWT twice over a 10m course and twice over a 30m course. The 6MWTs were performed in accordance with the American Thoracic Society guidelines. OUTCOME MEASURES 6MWD was assessed and predicted distance was calculated based on a range of reference equations. RESULTS The 6MWD on the 10m course was 49.5m shorter than on the 30m course, which was statistically significant (95% CI 39.4 to 59.6). By using existing reference equations for a 6MWT conducted on the 10m course, the predicted distance is highly overestimated (with a range of 30% to 33%) and the average distance as a percentage of the predicted value is 8%pred lower compared to a 6MWT conducted on the 30m course, resulting in a worse representation of a COPD patients functional exercise capacity. CONCLUSION This study shows that the impact of course length on the 6MWD and on the use of reference equations in patients with COPD is substantial and clinically relevant (based on the most conservative published minimum clinically important difference). Therefore, existing reference equations established for a 6MWT conducted over a 30m (or longer) course cannot be applied to predict the distance achieved on the 6MWT on a 10m course, which is frequently used in primary care physiotherapy practices for patients with COPD.

The first reference equations for the 6-minute walk distance over a 10 m course

Rationale As primary care practice space is mostly limited to 10 m, the 6-minute walk test (6MWT) over a 10 m course is a frequently used alternative to evaluate patients’ performance in COPD. Considering that course length significantly affects distance walked in 6 minutes (6MWD), this study aims to develop appropriate reference equations for the 10 m 6MWT. Methods 181 healthy subjects, aged 40–90 years, performed two standardised 6MWTs over a straight 10 m course in a cross-sectional study. Results Average distance achieved was 578±108 m and differed between males and females (p<0.001). Resulting sex-specific reference equations from multiple regression analysis included age, body mass index and change in heart rate, explaining 62% of the variance in 6MWD for males and 71% for females. Conclusions The presented reference equations are the first to evaluate 6MWD over a 10 m course and expand the usefulness of the 6MWT.

Development of a framework to describe goals and content of exercise interventions in physical therapy: a mixed method approach including a systematic review

Abstract Background: Exercise interventions in physical therapy (PT) are often not well described in research reports. Omitting details of the intervention hampers the transfer to daily clinical practice. Objective: To develop a framework for describing goals and content of exercise interventions, in order to provide structured and detailed information for use in research reports. Methods: A framework was developed in three steps using a mixed method approach. First, the scientific literature was systematically searched for available methods to describe PT interventions. An inventory of these methods was made and relevant elements were extracted. Second, based on the results of the literature search, a global framework was developed by a focus group of experts in the field of PT. Third, the framework was field tested by describing four different exercise interventions, leading to a final version. Results: In the developed framework intervention goals at the level of body functions and activities/participation were listed using the International Classification of Functioning, Disability and Health. To guide the description of the content of the exercise intervention a list of intervention details was developed, which was derived from an existing classification of PT interventions. Goals and content of exercise interventions were linked. Field testing of the framework led to adequate descriptions of exercise interventions. Conclusion: The developed framework is a promising first step in offering a feasible guide for a structured and detailed description of goals and content of exercise interventions within research reports.

Phenotypic Variation in Patients with Chronic Obstructive Pulmonary Disease in Primary Care

Introduction. Despite the high number of inactive patients with COPD, not all inactive patients are referred to physical therapy, unlike recommendations of general practitioner (GP) guidelines. It is likely that GPs take other factors into account, determining a subpopulation that is treated by a physical therapist (PT). The aim of this study is to explore the phenotypic differences between inactive patients treated in GP practice and inactive patients treated in GP practice combined with PT. Additionally this study provides an overview of the phenotype of patients with COPD in PT practice. Methods. In a cross-sectional study, COPD patient characteristics were extracted from questionnaires. Differences regarding perceived health status, degree of airway obstruction, exacerbation frequency, and comorbidity were studied in a subgroup of 290 inactive patients and in all 438 patients. Results. Patients treated in GP practice combined with PT reported higher degree of airway obstruction, more exacerbations, more vascular comorbidity, and lower health status compared to patients who were not referred to and treated by a PT. Conclusion. Unequal patient phenotypes in different primary care settings have important clinical implications. It can be carefully concluded that other factors, besides the level of inactivity, play a role in referral to PT.

Authors’ response: what determines which 6MWT is conventional?

We thank the co-chairs of the joint American Thoracic Society (ATS) and the European Respiratory Society (ERS) task force for their comments on our paper and interest in our article on reference values for the 6-min walk test (6MWT) performed over a 10m course. In their correspondence, the shorter course length is considered as one specific protocol deviation from the ATS statement1 that does not represent a conventional 6MWT. What is the ‘conventional’ 6MWT? Fourteen years ago, the ATS guidelines were published with the advice to test on a 30m course. However, at that time some studies used other course lengths, as was mentioned in the statement.1 Since then, more studies2–4 and healthcare providers have used a shorter course length due to space limitations. Moreover, …