Background: Suboptimal health status (SHS) measurement has now been recognized as an essential construct in predictive, preventive, and personalized medicine. Currently, there are limited tools, and an ongoing debate about appropriate tools. Therefore, it is crucial to evaluate and generate conclusive evidence about the psychometric properties of available SHS tools.
Objective: This research aimed to identify and critically assess the psychometric properties of available SHS instruments and provide recommendations for their future use.
Methods: Articles were retrieved by following the guidelines of the PRISMA checklist, and the robustness of methods and evidence about the measurement properties was assessed using the adapted COSMIN checklist. The review was registered in PROSPERO.
Results: The systematic review identified 14 publications describing four subjective SHS measures with established psychometric properties; these included the Suboptimal Health Status Questionnaire-25 (SHSQ-25), Sub-health Measurement Scale Version 1.0 (SHMS V1.0), Multidimensional Sub-health Questionnaire of Adolescents (MSQA), and the Sub-Health Self-Rating Scale (SSS). Most studies were conducted in China and reported three reliability indices: (1) the internal consistency measured by Cronbach's α value ranged between 0.70 and 0.96; (2) the test-retest reliability; and (3) the split-half reliability coefficient values ranged between 0.64 and 0.98, and between 0.83 and 0.96, respectively. For the values of validity coefficients in the case of SHSQ-25 > 0.71, the SHMS-1.0 ranged from 0.64 to 0.87, and the SSS ranged from 0.74 to 0.96. Using these existing and well-characterized tools rather than constructing original tools is beneficial, given that the existing choice demonstrated sound psychometric properties and established norms.
Conclusions: The SHSQ-25 stood out as being more suitable for the general population and routine health surveys, because it is short and easy to complete. Therefore, there is a need to adapt this tool by translating it into other languages, including Arabic, and establishing norms based on populations from other regions of the world.
Keywords: a systematic review; instruments; measurement; psychometrics; reliability; sub-optimal health status; tools; validity.