Walking Speed Predicts Frailty, Survival, and Other Outcomes in Older Patients With Blood Cancers

Walking speed was a reliable indicator of frailty among older patients with blood cancers, and this frailty measure was a more accurate predictor of survival and other clinical outcomes than patients’ chronologic age, cancer type, and type of treatment, according to researchers. The findings, published recently in Blood, suggest that this rapid screening test should be a standard part of medical assessment in this patient population.

“Despite the availability of many validated tests, few frailty measures have been routinely integrated into general clinical practice due to limited time and resources,” study investigator Jane A. Driver, MD, MPH, of the Geriatric Research Education and Clinical Center of the U.S. Department of Veterans Affairs, told ASH Clinical News. “Our work shows that 4-meter gait speed, which takes less than 30 seconds to measure and can be easily obtained with other vital signs, is as valuable a predictor of clinical outcomes as a 15-minute geriatric assessment. These findings could transform the way we assess functional status in the clinic and also how we individualize treatment decisions.”

In this study, Dr. Driver and investigators enrolled 488 people older than 75 years (mean age = 79.7±4 years) who presented to Dana-Farber Cancer Institute for an initial consultation in the myelodysplastic syndromes/leukemia, myeloma, or lymphoma clinics. Assessment included standard screening for cognitive impairment, as well as frailty screening with gait speed and grip strength tests.

In addition, a subset of 314 patients were followed for at least six months to track unplanned hospital or emergency department use. The authors did not observe any meaningful differences in baseline characteristics between the subset of 314 patients in this group and the other study participants.

“These findings could transform the way we assess functional status in the clinic and also how we individualize treatment decisions.”

—Jane A. Driver, MD, MPH

Researchers used the 4-m gait speed test developed by the National Institutes of Health: From a standing start, participants were asked to walk at a usual pace for 4 meters (approximately 13 feet), and the speed was recorded in meters per second (m/s) using a stopwatch. Thirty-three non-ambulatory patients were recorded as having a gait speed of zero.

Grip strength was evaluated using the Jamar Hand Dynamometer, which measured strength in patients’ dominant hand.

To be considered “frail,” patients had at least three of the following characteristics:

• unintentional weight loss
• self-reported exhaustion
• low energy expenditure
• slow gait speed
• weak grip strength

Participants were followed for an average of 13.8 months; about one-quarter of patients (24.6%) died during follow-up. In the subset of 314 patients followed for hospital resource use, 60 patients (19.1%) had an unplanned hospitalization and 53 (16.8%) had an emergency department visit.

In the overall cohort, the mean gait speed was 0.73 m/s and the mean grip strength was 24.6 kg.

Gait speed was examined as a continuous variable, and the authors found that, for every 0.1-m/s reduction in gait speed, there was a 22% increase in mortality (hazard ratio [HR] = 1.22; 95% CI 1.15-1.30). This also was accompanied by a 33% increase in unplanned hospitalizations (odds ratio [OR] = 1.33; 95% CI 1.16-1.51) and a 34% increase in emergency department visits (OR=1.34; 95% CI 1.17-1.53). P values were not provided for these comparisons.

Four-meter gait speed proved to be a stronger predictor of survival than age, cognitive impairment, type of cancer, and other factors in models that adjusted for Eastern Cooperative Oncology Group (ECOG) performance status score (TABLE 1).

Walking speed also was an incremental predictor of median, one-year, and two-year survival (TABLE 2).

Grip strength was predictive of poorer survival in ECOG-adjusted models, as well: Every 5-kg decrease in grip strength in patients with good ECOG performance status was associated with poorer survival (adjusted HR=1.24; 95% CI 1.07-1.43; p value not provided).

However, there was no association between grip strength and the frequency of hospital use or emergency department visits.

“Gait is a complex activity that reflects the function of many organ systems and is a global measure of a person’s health,” Dr. Driver added. “Thus, its value in the prediction of clinical outcomes may be greater than traditional disease-specific biomarkers used in predictive models for hematologic malignancies. It can serve as a good complement to conventional biomarkers by providing information on overall health status.”

The study’s recruitment of patients from a single large tertiary center is a limitation, as it may reduce the generalizability of the findings.

“Further studies, including clinical trials, are needed to assess the utility of gait speed in individualizing specific treatment plans, treatment tolerance and toxicity, and quality of life for older adults with blood cancers,” Dr. Driver concluded. “In addition, gait speed could be used to follow health status longitudinally, as it is known to be sensitive and responsive to change across time.”

The authors report no relevant conflicts of interest.

References

Liu M, DuMontier C, Murillo A. Gait speed, grip strength and clinical outcomes in older patients with hematologic malignancies. Blood. 2019 June 5. [Epub ahead of print]