Wearable step cadence during chemotherapy and survival

In a single-centre cohort of 213 people receiving outpatient chemotherapy, faster peak walking cadence on a Fitbit was associated with lower mortality after adjustment for clinical factors including age, cancer stage and performance status (hazard ratio 0.87 per 10 steps per minute, 95% CI 0.77 to 0.98). Daily step count was not independently associated. This small, preliminary observational study cannot show that changing cadence changes outcomes.

What did the chemotherapy wearable study measure?

The study by Low and colleagues in JCO Clinical Cancer Informatics enrolled 213 people with solid tumours at one NCI-designated cancer centre (206 had usable Fitbit data). Participants wore a Fitbit Inspire 2 or 3 for up to 90 days during outpatient chemotherapy and were followed for a median of 2.53 years. During follow-up, 90 people died.

The three measures were daily step count, peak gait cadence (the fastest one-minute walking pace) and activity fragmentation (how often someone switches from active to sedentary).

Before adjustment, all three were associated with survival, including higher step count (hazard ratio 0.87 per 1,000 steps). After adjusting for age, cancer stage, cancer type, clinician-rated performance status and patient-reported physical function, step count dropped out. Peak cadence (HR 0.87, 95% CI 0.77 to 0.98) and fragmentation (HR 1.02, 95% CI 1.00 to 1.04) stayed associated.

How much weight can these findings carry?

Not a great deal yet. The authors call the results preliminary. The sample was relatively small and mixed in cancer types and treatment history. Cause of death was not recorded, comorbidities were not assessed, and physical function was not measured by a performance test.

Enrolment was also limited to people with smartphones who could read and write in English, which the authors say may have selected people with better clinical outcomes.

An observational design also cannot separate a cause from a marker. A slower pace may simply reflect how unwell someone already is, which adjustment for stage and performance status can only partly capture.

For step counts in the general population, see the research on 7,000 versus 10,000 steps.

The bottom line

• In 213 people on outpatient chemotherapy, faster peak walking cadence on a Fitbit was associated with lower mortality after adjustment (HR 0.87 per 10 steps per minute).
• Daily step count lost its statistical association after adjustment, while cadence and activity fragmentation remained associated.
• This is a small single-centre observational study with selection limits, and the authors describe it as preliminary.