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Active, Not Recruiting

NCT Number: NCT05505552

Effects of Vitamin K on Lower-extremity Function in Adults With Osteoarthritis:

The overall goal of this pilot randomized trial is to obtain necessary prerequisite data to conduct a randomized controlled intervention to test the effect of vitamin K supplementation on knee osteoarthritis progression and related functional decline. To address critical parameters required to design this larger RCT, we will conduct a double-blind, 2-armed, parallel-group intervention study, with a placebo run-in, in which 50 adults with mild to moderate knee OA and low baseline vitamin K status will be randomly assigned to 1 mg phylloquinone/day or matching placebo, and treated for 6 months. Specifically, we will: (1) compare the effects of 1 mg/day phylloquinone vs. placebo on the non-functional circulating form of MGP; (2) estimate rates of recruitment and retention, follow-up rates and reasons for loss to follow-up, response rates to questionnaires, adherence/compliance rates, and potential for site differences; and (3) determine the responsiveness of the Osteoarthritis Research Society International (OARSI)-recommended performance-based tests of physical function in adults with low vitamin K status and mild to moderate knee osteoarthritis. We will also obtain preliminary data on the distribution of MGP genotype at two clinical sites for effect size generation.

As of February 2025, based on attrition rate below what was initially expected, we revised our planned enrollment from 50 to 35, to achieve the original goal of 30 completers. This was approved by the study sponsor.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Osteo Arthritis Knee Arthritis Joint Diseases Musculoskeletal Diseases Osteoarthritis Rheumatic Diseases

Age range

50 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Tufts University, Boston, Massachusetts, United States

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 50 years
  • Male or post-menopausal female (no menses in the last year)
  • Plasma phylloquinone <1.0 nmol/L
  • Chronic knee discomfort based on affirmative response to the question "During the past 12 months, have you had pain, aching, or stiffness in or around your knee(s) on most days for at least one month?"
  • Kellgren-Lawrence (KL) grade 2-3 in at least one knee
  • Ability to understand study procedures and to comply with them for the entire length of the study
  • Ability to answer questions by phone
  • Ability to swallow capsules

Exclusion criteria

  • KL grade 4 in at least one knee
  • Inability to walk
  • Cognitive impairment (based on a Montreal Cognitive Assessment Test score ≤ 17)
  • Widespread pain
  • Malabsorption disorders (e.g. advance liver disease, stage 4 or 5 chronic renal disease, Crohn's disease, celiac sprue)
  • Serious medical conditions or impairments that, in the view of the investigator, would obstruct study participation
  • Plan to permanently relocate from the greater Boston, MA or Chapel Hill NC areas during the trial period
  • Planned knee or hip arthroplasty during the study period
  • Undergoing cancer treatment
  • < 50 years old
  • Circulating phylloquinone ≥ 1.0 nmol/L
  • Warfarin (Jantoven) use
  • Use of other investigational drugs
  • Use of herbal, botanical or vitamin K supplements
  • Use of assistive walking devices

Treatment and study plan

Vitamin K

Dietary Supplement

1 mg/day phylloquinone (vitamin K1)

Other names: Phylloquinone

Placebo

Dietary Supplement

Placebo capsule once daily

Primary outcomes

  1. Plasma uncarboxylated matrix gla protein

    Time frame: 24 weeks

    Plasma uncarboxylated matrix gla protein is considered a functional indicator of vitamin K status. We will evaluate how it changes in response to 1 mg/d vitamin K supplementation in adults with low vitamin K status at baseline and with radiographic knee OA.

Secondary outcomes

  1. Plasma phylloquinone

    Time frame: 24 weeks

    Circulating phylloquinone is considered a global indicator of vitamin K status. We will evaluate how it changes in response to 1 mg/d vitamin K supplementation in adults with low vitamin K status at baseline and with radiographic knee OA.

Other outcomes

  1. Lower-extremity function - self reported

    Time frame: 12 and 24 weeks

    The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function index is a disease-specific, self-administered questionnaire, for assessing health status and health outcomes in osteoarthritis of the knee and/or hip. WOMAC function scores range from 0-68, with lower scores reflecting better function.

  2. Lower-extremity function - objective measures

    Time frame: 24 weeks

    40-m fast gait speed, Chair stand test, Stair climb test, Timed-up-and-go test, 6 min walk test are measures of lower-extremity function recommended by the Osteoarthritis Research Society International to test physical performance in people with knee OA.

  3. Knee pain

    Time frame: 12 and 24 weeks

    Knee pain, which is symptomatic of OA, will be evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Measurement of Intermittent and Constant Osteoarthritis Pain (ICOAP) self-reported questionnaires. WOMAC pain scores range from 0-20, with higher scores reflecting more pain. ICOAP scores range from 0-100, with higher scores reflecting more pain.

Sponsors and collaborators

Lead sponsor

Tufts University

Other

Collaborators

  • Tufts Medical Center
  • University of Massachusetts, Worcester
  • University of North Carolina, Chapel Hill

Registry information

Official study title

Effects of Vitamin K on Lower-extremity Function in Adults With Osteoarthritis: A Randomized Controlled Pilot Trial

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Aug 17, 2022
Registry last updated
Sep 17, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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