Minimum Performance on Clinical Tests of Physical Function to Predict Walking 6,000 Steps/Day in Knee Osteoarthritis: An Observational Study.
Study Goal
The researchers aimed to identify minimum performance thresholds on clinical tests of physical function that predict walking ≥6,000 steps/day in people with knee osteoarthritis.
Results Summary
The study found specific performance thresholds on physical function tests (5 times sit-to-stand, walking speed, and 400-meter walk) that predict walking ≥6,000 steps/day with high specificity, suggesting these thresholds may indicate inadequate physical ability for daily walking in knee OA patients.
Population
1,925 participants with knee osteoarthritis (mean age 65.1 ± 9.1 years, mean BMI 28.4 ± 4.8 kg/m²).
Effective Dosage
Not applicable (study measured steps/day, not a dosage).
Duration
Accelerometer data collected over 1 week.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
- | increase | walking ≥6,000 steps/day | people with knee osteoarthritis (OA) | - | predictive to | #1 |
- | no change | people with knee OA who develop functional limitation over time from those who do not | people with knee OA | - | discriminate | #2 |
5 times sit-to-stand test | increase | walking ≥6,000 steps/day | people with knee OA | ≤11.4 seconds | minimum performance threshold | #3 |
walking speed (tested over 20 meters) | increase | walking ≥6,000 steps/day | people with knee OA | ≥1.2 m/s | minimum performance threshold | #4 |
400-meter walk test | increase | walking ≥6,000 steps/day | people with knee OA | ≤5.0 minutes | minimum performance threshold | #5 |
Rehabilitation | increase | physical function | people with knee OA | - | may be indicated to address underlying impairments limiting physical function | #6 |
OBJECTIVE: Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not. METHODS: Using data from the Osteoarthritis Initiative, we quantified daily walking as average steps/day from an accelerometer (Actigraph GT1M) worn for ≥10 hours/day over 1 week. Physical function was quantified using 3 performance-based clinical tests: 5 times sit-to-stand test, walking speed (tested over 20 meters), and 400-meter walk test. To identify minimum performance thresholds for daily walking, we calculated physical function values corresponding to high specificity (80-95%) to predict walking ≥6,000 steps/day. RESULTS: Among 1,925 participants (mean ± SD age 65.1 ± 9.1 years, mean ± SD body mass index 28.4 ± 4.8 kg/m CONCLUSION: Not meeting these minimum performance thresholds on clinical tests of physical function may indicate inadequate physical ability to walk ≥6,000 steps/day for people with knee OA. Rehabilitation may be indicated to address underlying impairments limiting physical function.