Reliability and Minimum Detectable Change for Common Clinical Physical Function Tests in Sarcopenic Men and Women

Area of Science:

• Gerontology
• Clinical Nutrition
• Rehabilitation Medicine

Background:

• Sarcopenia and malnutrition are prevalent in older adults, impacting muscle strength and physical function.
• Reliable and valid clinical measurements are crucial for assessing and managing these conditions.

Purpose of the Study:

• To determine the test-retest reliability and minimum detectable change (MDC) scores for common clinical measurements.
• To evaluate these metrics in a multiethnic sample of sarcopenic, malnourished men and women.

Main Methods:

• Participants (N=257) visited a laboratory seven times over 25-26 weeks.
• Measurements included Short Physical Performance Battery (SPPB), handgrip strength, and isokinetic leg strength at slow and fast velocities.
• Reliability was assessed across multiple familiarization and testing sessions.

Main Results:

• Intraclass correlation coefficients (ICCs) for handgrip strength, gait speed, SPPB, and isokinetic leg strength were significantly greater than 0.
• Most variables showed systematic increases after familiarization, with some variability beyond baseline.
• ICCs and standard errors of measurement (SEMs) generally improved with familiarization.

Conclusions:

• At least one familiarization trial is necessary for accurate measurements in sarcopenic, malnourished older adults.
• A tiered approach to interpreting clinical significance, including effect magnitude and MDC, is recommended.