The CHUMS (Collaborative Home Uterine Monitoring Study) clinical trial - What does it really say?

Abstract

We observed with interest the recent publication of the CHUMS (Collaborative Home Uterine Monitoring Study) Group on home uterine activity monitoring [The Collaborative Home Uterine Monitoring Study (CHUMS) Group. A multicenter randomized controlled trial of home uterine monitoring: Active versus sham device. Am J Obstet Gynecol 1995;173:1120-7]). This study was previously presented in public forum to the Food and Drug Administration OB/GYN Medical Devices Advisory Panel on April 24, 1995; several concerns with the study design were addressed by a number of perinatologists in attendance. First, the study used a control group that received additional high-risk nursing care, including daily nursing contact and sham monitor. Because of this treatment of the control group, the study design was insufficient to detect the incremental benefit that the home uterine activity monitoring device itself could provide over intensive daily nursing contact. Further criticisms of the study included enrollment of patients who would likely not benefit from home uterine activity monitoring (e.g., placenta previa, hypertension), the use of a uterine activity threshold of six contractions per hour instead of the more commonly accepted four contractions per hour, and a high patient dropout rate of 34.8% of those randomized. In the published abstract we now find that the potential benefits of home uterine activity monitoring were further diluted by not allowing for emergency or as-needed patient monitoring and by early discontinuation of home uterine activity monitoring at the patient's first episode of preterm labor (regardless of gestational age). In addition, the data analysis did not account for scheduled or unscheduled physician or hospital visits and did not analyze prophylactic tocolytic use within each group. In spite of the above, the study demonstrates a trend in birth outcomes favoring the Active group. When analyzed individually, deliveries at ≤36 weeks appear to be less frequent in the Active group (33.0% vs 39.2%) and mean birth weights appear to be greater (p < 005, Yates' corrected χ2 test, Student t test). Additionally, the mean length of the neonatal intensive care unit stay appears to be less in the Active group (13.2 vs 17.0 days). The difference in total neonatal intensive care unit days for the Active group compared with the Sham group is 1326 days. At approximately $2000 per neonatal intensive care unit day, the addition of home uterine activity monitoring saved $2,652,000. Assuming the incremental cost of the home uterine activity monitoring device to be $35 per day, these savings occurred at an expense of $757,393 (574 pregnancies × 37.7 mean days/pregnancy × $35/day), yielding a net savings of $1,894,607, or $3301 per monitored high-risk pregnancy. We are concerned that the negative conclusions drawn by the authors of the CHUMS study are without merit and are in conflict with those of other recent trials.1Wapner RJ Cotton DB Artal R Librizzi RJ Ross MG A randomized multicenter trial assessing a home uterine activity monitoring device used in the absence of daily nursing contact.Am J Obstet Gynecol. 1995; 172: 1026-1034Abstract Full Text PDF PubMed Scopus (42) Google Scholar, 2Mou SM Sunderji SG Gall S How H Patel V Gray M et al.Multicenter randomized clinical trial of home uterine activity monitoring for the detection of preterm labor.Am J Obstet Gynecol. 1991; 165: 858-866Abstract Full Text PDF PubMed Scopus (64) Google Scholar The Food and Drug Administration has now approved three home uterine activity monitoring systems for preterm use on the basis of clinical data formally submitted to and reviewed by the Food and Drug Administration. We feel that the CHUMS Group study data and conclusions should be carefully scrutinized in this context. 6/8/73589