Patients with worse mental health report more physical limitations after adjustment for physical performance

To determine whether mental health scores are associated with self-reported physical limitations after adjustment for physical performance. Patient-reported physical limitations are widely used to assess health status or the impact of disease. However, patients' mental health may influence their reports of their physical limitations.

Mental health and physical limitations were measured using the SF-36v2 mental health and physical functioning subscales in a cross-sectional study of 1024 participants. Physical performance was measured using tests of strength, endurance, dexterity, and flexibility. Multivariable linear regression was performed to examine the relationship between self-reported mental health and physical limitations adjusting for age, gender, race/ethnicity, education, body mass index, and measured physical performance.

The score distributions for mental health and physical functioning were similar to that of the United States population in this age range. In unadjusted analyses, every 10-point decline in mental health scores was associated with a 4.8-point decline in physical functioning scores (95% Confidence Interval (CI) = -4.2 to -5.3; p < .001). After adjusting for covariables including measured physical performance, every 10-point decline in mental health scores was associated with a 3.0-point decline in physical functioning scores (95% CI = -2.5 to -3.6; p < .001).

People with poor mental health scores seem to report more physical limitations than would be expected based on physical performance. When comparing self-reported physical limitations between groups, it is important to consider differences in mental health.