Warm hands, less pain: Discover how heated mittens offer new hope for managing osteoarthritis symptoms in this groundbreaking study.
Study: Heated Mittens for Patients with Hand Osteoarthritis: A Randomized Trial. Image Credit: Zay Win Hatal / Shutterstock.com
In a recent study published in the BMJ, researchers assess the impact of heated mittens on hand osteoarthritis (OA) symptoms.
How does heat treat OA?
Hand OA causes inflammation of the first and third joints of the second to fifth fingers, which leads to pain, reduced physical function, and a decline in quality of life. Despite the exploration of pharmacological and surgical treatments for hand OA, there remains a lack of effective therapies for this condition.
Heat has been historically used to produce symptomatic and functional improvements in numerous inflammatory conditions, including OA. Heat increases blood flow, thereby enhancing oxygen and nutrient supply.
Numerous studies have reported heat-related alleviation of OA symptoms, which has supported conditional recommendations for its use in the 2020 American College of Rheumatology (ACR) guidelines. Previously, using heated mittens required clinic visits; however, recent advancements have led to the development of battery-driven mittens.
About the study
The trial was completed by 91 and 95 participants in the heated and sham mittens groups, respectively. The mean participant age was 71, and 87% of the study cohort were women.
All patients met the ACR criteria for hand OA and were functionally rated at 40 or above using the Australian/Canadian (AUSCAN) Osteoarthritis Hand Index. The median duration of OA was ten years.
Study participants were randomly assigned to wear either electrically heated or sham mittens during winter months. Both gloves were designed identically, with light-emitting diode (LED) indicators showing when the heating was on and the intensity of the heating. However, heating was disabled for the sham set of gloves.
All participants were asked to wear the mittens for 15 minutes or more every day for six weeks and record their for the most symptomatic time of day. The temperature of the gloves was adjustable.
The primary study outcomes included changes in AUSCAN function and pain. Hand-related issues using the visual analog score (VAS) and grip strength were also recorded.
Study findings
The heated mittens group wore them for a mean of 38 out of 42 days, compared to 37 days for the sham mittens group. The median number of times they used mittens was once daily in both groups, and the mean duration was 37 and 25 minutes, respectively. Both groups preferred the high-intensity heating setting.
At least 15 minutes of wear time was reported for 36 and 34 days in the heated and sham mittens group, respectively. Heated mittens use was associated with a mean reduction in AUSCAN function score by -6.3 points over the study period as compared to -3.3 points in the sham mittens group. This reduction was not statistically significant, indicating a numerical difference favoring heated mitten use.
The mean AUSCAN pain score reduction in the heated mittens group was 5.9 points greater than that of the sham mittens group. There was no significant change in VAS score or grip strength; however, AUSCAN stiffness decreased by an average of 6.3 points more in the heated mittens group.
The number of participants taking pain-relieving drugs declined from 42% to 36% and from 50% to 46% in the heated and sham mittens groups, respectively.
Conclusions
The use of heated mittens led to 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 from heated mittens as compared to ordinary mittens in hand problems related to OA.
Since heat application is a simple and safe method, it has been recommended for use in OA; however, there remains a lack of evidence supporting its benefits for this indication. Moreover, emotional enthusiasm towards their use of heated mittens increases the confounding effect on self-reported outcomes like pain and stiffness.
In the future, studies lasting longer than six weeks in duration may provide essential insights into how OA patients can experience symptomatic improvement. Additional research is also needed to investigate heated mittens' functional and pain-relieving effects.
Journal reference:
- Bartholdy, C., Dassing, A., Stisen, Z., et al. (2024). Heated Mittens for Patients with Hand Osteoarthritis: A Randomized Trial. BMJ. doi:10.1136/bmj-2023-078222.