The Effects of Patient and Visit Characteristics on Health Outcomes in Knee Osteoarthritis
NCT Number: NCT06574191
Status: NOT_YET_RECRUITING
Study Type: INTERVENTIONAL
Phases: NA
Conditions: Knee Osteoarthritis
Interventions: DRUG: Topical Diclofenac gel
Sponsor: University of California, Davis
Collaborators: National Institute on Aging (NIA)|Beth Israel Deaconess Medical Center
Sex: ALL
Age: ADULT, OLDER_ADULT
Enrollment: 220
Study Design: Allocation: NA|Intervention Model: SINGLE_GROUP|Masking: NONE|Primary Purpose: BASIC_SCIENCE
Start Date: 2024-09-15
Completion Date: 2027-07-13
Locations: University of California Davis Health, Sacramento, California, 95817, United States

Summary:
The goal of this clinical trial is to understand the patient and clinic visit characteristics that affect health outcomes for individuals with knee osteoarthritis (OA) pain using topical diclofenac gel. The main questions it aims to answer are:

* What baseline patient characteristics predict response to topical diclofenac?
* Does patient physiology during the study visit predict response to topical diclofenac?
* Do study visit characteristics predict response to topical diclofenac?

Participants will:

* attend 2 study visits to complete study questionnaires and have blood drawn
* apply topical diclofenac to their knee for 8 weeks
* complete biweekly questions about knee pain and diclofenac use between study visits

Primary Outcome Measures: Knee Pain, Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain score from the index knee at 8 weeks. Score range 0-20. Higher scores signify worse pain., 8 weeks|Knee Function, Western Ontario and McMaster Universities Arthritis Index (WOMAC) physical function score from the index knee at 8 weeks. Score range 0-68. Higher scores signify worse function., 8 weeks
Secondary Outcome Measures: Global Impressions, Baseline-adjusted end of visit global impression ratings from study visit video recordings. Each global impression is measured on a 1-9 scale. Global impressions include engagement (clinician and patient), friendliness (clinician and patient), relaxed (clinician and patient), empathic (clinician), reciprocity (dyad), business-like (clinician), dominant (clinician), confident (patient), and pleased (patient). We will construct a Global Impression Summative Scale Score if a preliminary round of psychometric evaluation determines that a combination of the individual construct scores can be constructed that has adequate internal consistency and unidimensionality., 30 minutes|Non-verbal Behaviors, Baseline-adjusted end of visit non-verbal behaviors from study visit video recordings. Each non-verbal behavior is measured as counts (number of times) or total length of time within a discrete period of time (i.e., 2 minutes) from the video. Nonverbal behaviors that will be counted or timed for both parties include: gaze duration and number, smile duration and number, number of nods, self-touch, and gestures. We will also assess the number of clinician backchannel responses while patients spoke, the number of instances of shared laughter between the dyads, and the length of time that both the patient and clinician spoke. We will construct a Non-verbal Behavior Summative Score if a preliminary round of psychometric evaluation determines that a combination of the individual construct scores can be constructed that has adequate internal consistency and unidimensionality., 30 minutes|Skin conductance index measure, Concordance in skin conductance response (measured in micro Siemens) from electrodes attached to the patient's and clinician's fingers over the course of the study visit will be calculated using an established approach (Marci CD, 2007; PMID 17299296) to create a single index value for the visit. The natural logarithm of this value will be taken to reduce skew. A value greater than 0 means more than 50% concordance in the data, a value less than zero means less than 50% concordance in the data., 30 minutes|Change in patient skin conductance response, Change in patient skin conductance response from beginning to end of the initial study visit in micro-Siemens as measured by skin electrodes. Change score will be calculated as mean skin conductance response for the first 2 minutes of the study visit minus the mean value for the last 2 minutes of the study visit., 30 minutes|Heart rate variability index measure, Concordance in heart rate variability, measured from electrodes attached to the patient and clinician, over the course of the study visit, will be calculated using established approaches (see references below). Concordance is quantified by the degree to which heart rate variability of the patient and clinician are "in-phase" or "anti-phase" linked (i.e., coordinated changes in the same or opposite direction) along the study visits.

https://pubmed.ncbi.nlm.nih.gov/29683720/ https://pubmed.ncbi.nlm.nih.gov/21910541/ https://pubmed.ncbi.nlm.nih.gov/24708502/ https://pubmed.ncbi.nlm.nih.gov/35315937/, 30 minutes|Change in patient RMSSD (root mean square of successive differences), The RMSSD component (proxy for high frequency heart rate variability) will be measured in the patient over the course of the study visit. Change score will be calculated as mean RMSSD value for the first 5 minutes of the study visit minus the mean value for the last 5 minutes of the study visit., 30 minutes