Dedicated call center (SOS-HAE) for hereditary angioedema attacks: study protocol for a randomised controlled trial

Hereditary angioedema, emergency management of attacks by a call center

OBJECTIVE

Hereditary angiœdema (HAE) is a rare autosomal dominant disease characterized by recurrent, unpredictable, potentially life-threatening swelling. Objective is to assess the management of the acute HAE attacks in the real life setting through a call center in France.

METHODS

A pre-specified ancillary study of SOS-HAE, a cluster-randomized prospective multicenter trial, was conducted. HAE patients were recruited from 8 participating reference centers. The outcome of interest was the rate of hospitalization.

RESULTS

onerhundred patients were included. The median (quartile) age was 38 (29-53) years, and 66 (66%) were female. Eighty (80%) patients had HAE type I, 8 (8%) had HAE type II and 12 (12%) patients had FXII-HAE. Fifty-one (51%) patients had experienced at least one time the call center during the follow-up. Nine over 166 (5%) attacks for 9 different patients resulted in hospital admission to the hospital (in the short-stay unit, ie, <24 h) during the follow-up period. During 2 years, there were 166 calls to call center for 166 attacks. All attacks were treated at home after call center contact.

CONCLUSIONS

Use of emergency departments and hospitalizations are reduced by the use of a coordinated national call center in HAE after therapeutic education program that promoted self-administration of specific treatment and use of call to call center.

TRIAL REGISTRATION

clinicalTrials.gov identifier: NCT01679912.

Specialist Advice Support for Management of Severe Hereditary Angioedema Attacks: A Multicenter Cluster-Randomized Controlled Trial

STUDY OBJECTIVE

Hereditary angioedema is a rare disease associated with unpredictable, recurrent attacks of potentially life-threatening edema. Management of severe attacks is currently suboptimal because emergency medical teams are often unaware of new specific treatments. The objective of this trial is to test whether a dedicated national telephone care-management strategy would reduce resource use during severe hereditary angioedema attacks.

METHODS

We conducted a cluster-randomized multicenter prospective trial of patients with a documented diagnosis of hereditary angioedema (type I, II or FXII hereditary angioedema). Participants were enrolled between March 2013 and June 2014 at 8 participating reference centers. The randomized units were the reference centers (clusters). Patients in the intervention arm were given a national free telephone number to call in the event of a severe attack. Emergency physicians in the SOS-hereditary angiœdema (SOS-HAE) call center were trained to advise or prescribe specific treatments. The primary outcome was number of admissions for angioedema attacks. Economic evaluation was also performed.

RESULTS

We included 100 patients in the SOS-HAE group and 100 in the control group. During the 2 years, there were 2,368 hereditary angioedema attacks among 169 patients (85%). Mean number of hospital admissions per patient in the 2-year period was significantly greater in the usual-practice group (mean 0.16 [range 0 to 2] versus 0.03 [range 0 to 1]); patient risk difference was significant: -0.13 (95% confidence interval -0.22 to -0.04; P=.02). Probabilistic sensitivity graphic analysis indicated a trend toward increased quality-adjusted life-years in the SOS-HAE group.

CONCLUSION

A national dedicated call center for management of severe hereditary angioedema attacks is associated with a decrease in hospital admissions and may be cost-effective if facilities and staff are available to deliver the intervention alongside existing services.