Overview

This study aims to evaluate the reliability and convergent validity of the Vietnamese version of the Pain Self-Efficacy Questionnaire (VIET-PSEQ) in patients with knee osteoarthritis (KOA). Pain self-efficacy refers to a person's confidence in managing their pain and maintaining daily activities despite it.

A total of 173 patients with KOA will be recruited at Gia Dinh People's Hospital using a convenient sampling method. Eligible participants are 50 years or older, diagnosed with KOA, and experiencing chronic knee pain. They will complete the VIET-PSEQ and other health-related questionnaires during an in-person interview.

The study will assess internal consistency (using Cronbach's alpha), test-retest reliability (by re-assessing a subgroup after 72 hours), and convergent validity by correlating VIET-PSEQ scores with EQ-5D-5L utility index. Additionally, linear regression analysis will examine how age, sex, pain severity, and education level influence pain self-efficacy.

The goal is to determine whether VIET-PSEQ is a reliable and valid tool for measuring pain self-efficacy in Vietnamese patients with KOA.

Eligibility

Inclusion Criteria:

Participants will be eligible for inclusion if they meet all of the following conditions:

• Age ≥ 50 years.
• Diagnosis of knee osteoarthritis (OA) according to the criteria of the American College of Rheumatology (ACR), confirmed by:
  1. application of ACR criteria by the investigator at the time of enrollment; or
  2. a prior diagnosis documented in medical records by a rheumatologist or musculoskeletal specialist.
• Presence of chronic pain related to knee OA, with current pain intensity ≥ 1 on the

  Visual Analog Scale (VAS).

• No acute flare of knee pain within the past 2 weeks.
• Ability to perform activities of daily living (with or without assistance).
• Ability to read, understand, and complete questionnaires in Vietnamese.
• Willingness to participate and provide informed consent.

Exclusion Criteria:

Participants will be excluded if they meet any of the following conditions:

• Diagnosis of severe psychiatric disorders (e.g., schizophrenia, severe anxiety disorders).
• Presence of cognitive impairment that interferes with the ability to comprehend or answer the questionnaire.
• Diagnosed with systemic inflammatory diseases such as rheumatoid arthritis, systemic lupus erythematosus, or gout.
• Presence of other chronic pain conditions (unrelated to knee OA) that are predominant and significantly affect mobility and daily functioning.
• History of intra-articular injection or knee surgery within the past 3 months.
• Questionnaire (PSEQ) with ≥ 20% of items missing or invalid.