The relationship between ambulatory step activity, self-reported physical functioning and standardised timed walking in patients with haematological malignancies

Abstract

Purpose. This cross-sectional study investigated the degree of association between the results of ambulatory step activity monitoring (SAM), self-reported physical functioning (SRPF) and the 6-minute standardised walking test (6-MWT) in cancer patients with haematological malignancies.

Method. Assessments of ambulatory SAM, SRPF and 6-MWT were assessed in 102 patients up to 122 days (mean 78 ± 35) after haematopoietic stem cell transplantation (HSCT). To determine the association between measures of walking, the Pearson product moment correlation coefficient (r) including the 95%CI and the r² were calculated. Simple linear regression analyses were performed to estimate the ambulatory step activity from SRPF and the 6-MWT.

Results. The average age was 47 years (±12) and body mass index 23.4 (±4). The correlations were low between ambulatory SAM outputs and SRPF (ranging from −0.32 to 0.34, p < 0.01), and very low between SAM outputs and 6-MWT, (ranging from 0.21 to 0.24). The correlation between SRPF and the 6-MWT was low (0.33, p < 0.01). The correlation between SRPF and the 6-MWT was low (0.33, p < 0.01). The 95%CIs were quite narrow around r. The shared variance (r²) between the SAM and SPPF ranged between 4% and 11% and the shared variance between the SAM and 6-MWT ranged between 0.5% and 18%. Linear regression yielded weak relationships and large standard errors of estimate between the SAM, SRPF and 6-MWT.

Conclusions. SRPF and the 6-MWT do not reflect daily walking activity. In clinical use (e.g. to evaluate the effects of a rehabilitation program), ambulatory step activity outputs can be considered an additional outcome to assess day-to-day walking activity in patients with haematological cancer after HSCT.

Keywords:

• Haematological malignancies
• exercise
• walking

Acknowledgements

We thank the patients for their willingness to take part in the study. We also thank Giuseppe Pichierri, MSc and Kei Shirato, MSc from the Institute of Human Movement Sciences and Sport, ETH, Zurich, Switzerland for performing the measurements and for instructing patients in the use of the SAM3. We thank Frank Stenner, MD (Department of Medical Oncology), and Urs Schanz, MD (Department of Haematology, both University Hospital Zurich), Felicitas Hitz, MD (Department of Oncology/Haematology, Cantonal Hospital St.Gallen), and Christian Taverna, MD (Department of Oncology/Haematology, Cantonal Hospital Muensterlingen) for referring their patients to the study. This work was supported by the Cantonal Cancer Committee of Zurich (Kantonal-Zürcherische Krebskommission) Switzerland and the Federal Office for Sport (Eidgenössische Sportkommission) Magglingen, Switzerland.