Clinical Abstracts

Heat Helps Cramps

Source: Akin MD, et al. Continuous low-level topical heat in the treatment of dysmenorrhea. Ob Gyn 2001;97:43-49.

Design and Setting: A randomized placebo-controlled parallel-group study in four groups (apparently a 2x2 design).

Subjects: This study included 84 women (81 completed) with moderate or severe menstrual pain.

Treatment Dose/Route/Duration: Women were assigned to an active or placebo device plus an active or placebo oral medication. The active device treatment was a kidney bean-shaped thin, heated, disposable medical device that adheres to the inside of the underwear in the pelvic region and supplies heat at a constant temperature of 38.9° C over 180 cm2 for 12 hours. The placebo device was an unheated patch. Patches were worn for 12 hours/d for two consecutive days. Active oral medication consisted of ibuprofen (400 mg tid) for two days.

Outcome Measures: Reduction in pain intensity score was calculated by taking differences from the patients’ baseline scores. Reduction in pain intensity score was measured by analysis of covariance procedures; pain relief scores were obtained by one-way analysis of variance. Overall means were analyzed by nonparametric one-way analysis of variance methods using Cochran-Mantel-Haenszel tests for pain-intensity reduction and Wilcoxon rank-sum tests for pain-intensity relief.

Results: All three treated groups had significantly greater pain relief than the double-placebo group; the heated patch with ibuprofen was not more effective than ibuprofen alone. The time to pain relief was significantly shorter for the combination of heated patch and ibuprofen (median 1.5 hours) compared to unheated patch plus ibuprofen (median 2.79 hours).

Complete relief during the study was achieved by 35% of the double-placebo group; 68% in the double-active (heated patch plus ibuprofen) group; 70% in the group treated with heated patch plus placebo; and 55% in the group receiving unheated patch plus ibuprofen. Compared to double placebo, there was a significant benefit for both groups receiving the heated patch but not the ibuprofen-only group. Two patients in the heated patch group and one in the unheated patch group reported skin redness. Skin pinkness after 12 hours was reported by 42.5% (17/40) of patients in the heated patch group compared to 12.2% (5/41) of subjects in the placebo patch group (a significant difference). Skin color normalized by the next morning in all but two patients. All patients reported normal skin color at the final interview (day 3-7).

Funding: Procter & Gamble supplied study devices and materials. The first author is a contractual employee of Health Quest Therapy and Research Institute; four of five of the remaining authors are employees of Procter & Gamble.

Comments: Science validates a home remedy! Hot water bottles and heating pads are common home treatments for dysmenorrhea, but I’ve never seen a study on heat treatment of cramps until this one. Clearly the company that funded the study is preparing to market this disposable heat-generating device. It sounds like a good idea; the patch definitely sounds preferable to toting a hot water bottle to a business meeting. It is stated that the device is expected to cost about $3 per heat patch. A hot water bottle or heating pad, of course, would be cheaper.

This may be the first menses-related product that men might borrow—a discreet source of warmth to treat an aching back or shoulder may well cross gender lines.