Warm hands, less pain: learn how heated mittens offer new hope in managing osteoarthritis symptoms in this groundbreaking study.
Study: Heated mittens for patients with hand osteoarthritis: a randomized trialL. Image Credit: Zay Win Hatal/Shutterstock.com
In a recent study published in the BMJ, researchers are evaluating the impact of heated mittens on hand osteoarthritis (OA) symptoms.
How does heat treat osteoarthritis?
Osteoarthritis of the hand causes inflammation of the first and third joints of the second to fifth fingers, leading to pain, reduced physical function and reduced quality of life. Despite the exploration of pharmacological and surgical treatments for hand osteoarthritis, there remains a lack of effective therapies for this condition.
Heat has historically been used to produce symptomatic and functional improvements in many inflammatory conditions, including osteoarthritis. Heat increases blood flow, improving the delivery of oxygen and nutrients.
Numerous studies have reported alleviation of heat-related osteoarthritis symptoms, supporting conditional recommendations for its use in the 2020 American College of Rheumatology (ACR) guidelines. Previously, using heated mittens required visits to the clinic; however, recent advances have led to the development of battery-powered mittens.
About the study
The trial was completed by 91 and 95 participants in the heated mitten and sham groups, respectively. The average age of participants was 71 years and 87% of the study cohort were women.
All patients met the ACR criteria for hand osteoarthritis and were functionally rated 40 or greater using the Australian/Canadian (AUSCAN) Hand Osteoarthritis Index. The median duration of osteoarthritis was ten years.
Study participants were randomly assigned to wear electrically heated mittens or pretend mittens during the winter months. Both gloves were designed identically, with light-emitting diode (LED) indicators showing when the heater was on and how intense it was. However, the heating was turned off for the fake glove set.
All participants were asked to wear the mittens for 15 minutes or more each day for six weeks and to record their most symptomatic time of day. The temperature of the gloves was adjustable.
Primary study outcomes included changes in AUSCAN function and pain. Hand-related problems using visual analog score (VAS) and grip strength were also recorded.
Study results
The heated mitten group wore them an average of 38 days out of 42, compared to 37 days for the fake mitten group. The median number of times they used mittens was once per day in both groups, and the average duration was 37 and 25 minutes, respectively. Both groups preferred the high intensity heating setting.
At least 15 minutes of wear was reported for 36 and 34 days in the heated and sham mitten groups, respectively. Use of heated mittens was associated with an average reduction in AUSCAN functional score of -6.3 points over the study period, compared to -3.3 points in the sham mitt group. This reduction was not statistically significant, indicating a numerical difference favoring the use of heated mittens.
The average reduction in AUSCAN pain score in the heated mitten group was 5.9 points greater than that in the sham mitten group. There was no significant change in VAS score or grip strength; however, AUSCAN stiffness decreased by an additional 6.3 points on average in the heated mitten group.
The number of participants taking painkillers decreased from 42% to 36% and 50% to 46% in the heated mitten and sham groups, respectively.
Conclusions
Use of heated mittens resulted in statistically significant and potentially useful improvements in hand pain and stiffness scores. There was no observable improvement in hand function, as assessed by AUSCAN.
Functional resolution was the most important outcome for patients. However, the current study could not establish additional benefits of heated mittens over regular mittens for OA-related hand problems.
Since the application of heat is a simple and safe method, its use has been recommended in cases of osteoarthritis; however, there remains a lack of evidence supporting its benefits for this indication. Additionally, emotional enthusiasm toward using heated mittens increases the confounding effect on self-reported outcomes like pain and stiffness.
In the future, studies lasting longer than six weeks could provide critical information on how patients with osteoarthritis may experience symptomatic improvement. Further research is also needed to study the functional and analgesic effects of heated mittens.
